SW8031133_HISTORICAL FILE_20040603

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SW kjQ3��3�
DOC TYPE
El CURRENT PERMIT
❑ APPROVED PLANS
HISTORICAL FILE
❑ COMPLIANCE EVALUATION INSPECTION
DOC DATE
2LAIL(d 03
YYWMMDD

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h Carolina
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mington, NC 28405 (Attu BEV
c� ' i33
11lIlIIlIll!'Ik1�111lII11!lI11lIIIllllli!l�IE1l1�1i1lFl�lillil

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P5 Form 3811, August 2001 Domestic Return Receipt 102595-02 M 1540
l

State Stormwater Management Systems
Permit No SW$ 031133
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER QUALITY
STATE STORMWATER MANAGEMENT PERMIT
HIGH DENSITY DEVELOPMENT
In accordance with the provisions of Article 21 of Chapter 143, General Statutes of North
Carolina as amended, and other applicable Laws, Rules, and Regulations
PERMISSION IS HEREBY GRANTED TO
Mr Bryan English
Georgetown Center
Brunswick County
FOR THE
construction, operation and maintenance of an infiltration trench in compliance with the
provisions of 15A NCAC 2H 1000 (hereafter referred to as the "stormwater rules') and the
approved stormwater management plans and specifications and other supporting data as attached
and on file with and approved by the Division of Water Quality and considered a part of this
permit
This permit shall be effective from the date of issuance until June 3, 2014, and shall be subject to
the following specified conditions and limitations
I. DESIGN STANDARDS
1 This permit is effective only with respect to the nature and volume of stormwater
described in the application and other supporting data
2 This stormwater system has been approved for the management of stormwater runoff as
described on page 3 of this permit, the Project Data Sheet The stormwater control has
been designed to handle the runoff from 22,241 square feet of impervious area This
system must be operated with a vegetated filter
3 The tract will be limited to the amount of built -upon area indicated on page 3 of this
permit, and per approved plans
4 All stormwater collection and treatment systems must be located in either dedicated
common areas or recorded easements The final plats for the project will be recorded
showing all such required easements, in accordance with the approved plans
5 The runoff from all built -upon area within the permitted drainage area of this project must
be directed into the permitted stormwater control system A permit modification must be
submitted and approved prior to the construction of additional built -upon area from
outside of the approved drainage area
2

State Stormwater Management Systems
Permit No SW8 031133
DIVISION OF WATER QUALITY
PROJECT DESIGN DATA SHEET
Project Name
Permit Number
Location
Applicant
Mailing Address
Application Date
Receiving Stream/River Basin
Stream Index Number
Classification of Water Body
Drainage Area, acres
Onsite, sq ft
Offsite, sq ft
Total Impervious Surfaces, sq ft
Design Storm
Trench Dimensions, LxWxH/Pipe Dia
Required Storage Volume, ft3
Provided Storage Volume, ft3
Bottom Elevation, FMSL
Temporary Storage Elevation, FMSL
Type of Soil
Time to Drawdown, hours
Georgetown Center
SW8 031133
Brunswick County
Mr Bryan English
4705 Southport -- Supply Hwy
Southport, NC 28461
June 3, 2004
Dutchman's Creek / Cape Fear
CPF17 18-88-9-3-(1)
"Sc Sw HQW"
065
28,155
none
22,241
101,
110' x 6' x 3 52'/6" & 120 x 4' x 3 52'/6"
1,782
1,806
23 88
2740
Baymeade
113
Seasonal High Water Table, FMSL 2188
3

State Stormwater Management Systems
Permit No SW8 431133
IL SCHEDULE OF COMPLIANCE
l The stormwater management system shall be constructed in its entirety, vegetated and
operational for its intended use prior to the construction of any built -upon surface
2 During construction, erosion shall be kept to a minimum and any eroded areas of the
system will be repaired immediately
3 The permittee shall at all times provide the operation and maintenance necessary to assure
the permitted stormwater system functions at optimum efficiency The approved
Operation and Maintenance Plan must be followed in its entirety and maintenance must
occur at the scheduled intervals including, but not limited to
a Semiannual scheduled inspections (every 6 months)
b Sediment removal
c Mowing and revegetation of slopes and the vegetated filter
d Immediate repair of eroded areas
e Maintenance of all slopes in accordance with approved plans and specifications
f Debris removal and unclogging of outlet structure, onfice device, flow spreader,
catch basins and piping
g Access to the outlet structure must be available at all times
4 Records of maintenance activities must be kept and made available upon request to
authorized personnel of DWQ The records will indicate the date, activity, name of
person performing the work and what actions were taken
The facilities shall be constructed as shown on the approved plans This permit shall
become voidable unless the facilities are constructed in accordance with the conditions of
this permit, the approved plans and specifications, and other supporting data
6 Upon completion of construction, prior to issuance of a Certificate of Occupancy, and
prior to operation of this permitted facility, a certification must be received from an
appropriate designer for the system installed certifying that the permitted facility has been
installed in accordance with this permit, the approved plans and specifications, and other
supporting documentation Any deviations from the approved plans and specifications
must be noted on the Certification A modification may be required for those deviations
7 if the stormwater system was used as an Erosion Control device, it must be restored to
design condition prior to operation as a stormwater treatment device, and prior to
occupancy of the facility
The permittee shall submit to the Director and shall have received approval for revised
plans, specifications, and calculations prior to construction, for any modification to the
approved plans, including, but not limited to, those listed below
a Any revision to any item shown on the approved plans, including the stormwater
management measures, built -upon area, details, etc
b Project name change
c Transfer of ownership
d Redesign or addition to the approved amount of built -upon area or to the drainage
area
e Further subdivision, acquisition, or sale of all or part of the project area The
project area is defined as all property owned by the permittee, for which
Sedimentation and Erosion Control Plan approval or a CAMA Major permit was
sought
f Filling in, altering, or piping of any vegetative conveyance shown on the approved
plan
n

State Stormwater Management Systems
Permit No SW$ 031133
9 The permittee shall submit final site layout and grading plans for any permitted future
areas shown on the approved plans, prior to construction If the proposed BUA exceeds
the amount permitted under this permit, a modification to the permit must be submitted
and approved prior to construction
10 A copy of the approved plans and specifications shall be maintained on file by the
Permittee for a minimum of ten years from the date of the completion of construction
ll At least 30 days prior to the sale or lease of any portion of the property, the pennittee
shall notify DWQ and provide the name, mailing address and phone number of the
purchaser or leasee An access/maintenance easement to the stormwater facilities shall be
granted in favor of the permittee if access to the stormwater facilities will be restricted by
the sale or lease of any portion of the property
12 The permittee must maintain compliance with the proposed built -upon area and ensure
that the runoff from all the built -upon is directed into the permitted system
13 The Director may notify the permittee when the permitted site does not meet one or more
of the minimum requirements of the permit Within the time frame specified in the notice,
the permittee shall submit a written time schedule to the Director for modifying the site to
meet minimum requirements The permittee shall provide copies of revised plans and
certification in writing to the Director that the changes have been made
14 The permittee must maintain the current permitted drainage area No additional runoff
from outside of the permitted drainage area boundary may enter the permitted stormwater
facilities without first applying for and receiving a permit modification
III. GENERAL CONDITIONS
This permit is not transferable except after notice to and approval by the Director In the
event of a change of ownership, or a name change, the permittee must submit a formal
permit transfer request to the Division of Water Quality, accompanied by a completed
name/ownership change form, documentation from the parties involved, and other
supporting materials as may be appropriate The approval of this request will be
considered on its ments and may or may not be approved The permittee is responsible
for compliance with all permit conditions until such time as the Division approves the
transfer request
2 Failure to abide by the conditions and limitations contained in this permit may subject the
Permittee to enforcement action by the Division of Water Quality, in accordance with
North Carolina General Statute 143-215 6A to 143-215 6C
3 The issuance of this permit does not preclude the Permittee from complying with any and
all statutes, rules, regulations, or ordinances which may be imposed by other government
agencies (local, state, and federal) which have jurisdiction
4 In the event that the facilities fail to perform satisfactorily, including the creation of
nuisance conditions, the Permittee shall take immediate corrective action, including those
as may be required by this Division, such as the construction of additional or replacement
stormwater management systems
5 The permittee grants DENR Staff permission to enter the property during normal business
hours for the purpose of inspecting all components of the permitted stormwater
management facility
6 The permit may be modified, revoked and reissued or terminated for cause The filing of
a request for a permit modification, revocation and reissuance or termination does not
stay any permit condition
5

State Stormwater Management Systems
Permit No SW8 031133
7 Unless specified elsewhere, permanent seeding requirements for the stormwater control
must follow the guidelines established in the North Carolina Erosion and Sediment
Control Planning and Design Manual
8 Approved plans and specifications for this project are incorporated by reference and are
enforceable parts of the permit
9 The permittee shall notify the Division any name, ownership or mailing address changes
within 30 days
Permit issued this the 3rd day of June 2004
NORTH CAROLINA ENVIRONMENTAL MANAGEMENT COMMISSION
'fA lfiifW Klimek, P E , Director
ot Division of Water Quality
By Authority of the Environmental Management Commission
2

State Stormwater Management Systems
Permit No SW8 031133
Georgetown Center
Stormwater Permit No SW8 031133
Brunswick County
Designer's Certifeation
I, , as a duly registered
in the State of North Carolina, having been authorized to observe (penodically/weekly/full time)
the construction of the project,
(Project)
for (Project Owner) hereby state that, to the best of
my abilities, due care and diligence was used in the observation of the project construction such
that the construction was observed to be built within substantial compliance and intent of the
approved plans and specifications
The checklist of items on page 2 of this form is included in the Certification
Noted deviations from approved plans and specification
Signature
Registration Number
Date
SEAL
7

State Stormwater Management Systems
Permit No SW8 031133
Certification Requirements
1 The drainage area to the system contains approximately the permitted acreage
2 The drainage area to the system contains no more than the permitted amount of
built -upon area
3 All the built -upon area associated with the project is graded such that the runoff
drains to the system
4 The outlet/bypass structure elevations are per the approved plan
5 The outlet structure is located per the approved plans
6 Trash rack is provided on the outlet/bypass structure
7 All slopes are grassed with permanent vegetation
8 Vegetated slopes are no steeper than 3 1
9 The inlets are located per the approved plans and do not cause short-circuiting of
the system
10 The permitted amounts of surface area and/or volume have been provided
11 Required drawdown devices are correctly sized per the approved plans
12 All required design depths are provided
13 All required parts of the system are provided, such as a vegetated shelf, and a
forebay
14 The overall dimensions of the system, as shown on the approved plans, are
provided
cc NCDENR-DWQ Regional Office
Brunswick County Building Inspections

�F W A ��� tilichael F Easley Governor
i Q William G Ross Jr, Secretary
North Carolina Department of Environment and Natural Resources
yAlan W Klimek P E Director
Q .0 Division of Water Quality
Coleen H Sullins Deputy Director
Division of Water Quality
May 10, 2004
Mr Bryan English
4705 Southport — Supply Highway
Southport, NC 28461
Subject REQUEST FOR ADDITIONAL IINFORNIATIO`
Stormwater Project No SWS 031133
Georgetown Center
Brunswick County
Dear Mr English
The Wilmington Regional Office received a Stormwater Management Permit Application for
Georgetown Center on April 29, 2004 A preliminary review of that information has determined that the
application is not complete The following information is needed to continue the stormvvater review
i 1 Please provide a legend on the plans Please indicate the wetlands line on the legend and
more clearly indicate the wetlands line on the plans
/ 2 Please provide the latitude and longitude on Section I of the application
3 Vincent Lewis, state soils scientist, must verify the location of the seasonal high water
table I will setup an appointment with Vincent and notify you of the date All utilities
must be marked on the site prior to the investigation
4 Please provide the name of the tributary that the site drains to on Section III Item 6 of the
application
Please revise the plans to show the vegetative filter detail The runoff in excess of 1"
must bypass the system prior to entering the system The excess runoff cannot pass
through the system If you cannot provide this bypass, please design the system for the
2" storm event
6 Please design the trench for a 40% void ratio q �- "to
7 The trench dimensions on the calculations are different than the dimensions on the
supplement My calculations show that you must provide 1,835 cubic feet of storage
Please revise
8 Please provide a cleanout elevation for the trench The sediment must be removed
annually or when the depth is reduced to 75% of the original design depth
9 Please provide a 4" layer of clean sand on the bottom of the system
Qar
N C Division of Water Quality 127 Cardinal Drive Extension [phone] Customer Servioe
Wilmington Regional Office Wilmington, NC 28405 [phone] Fax [phone] NMEIOR

1+Ir Bryan English
Page 2
May 10, 2004
Please note that this request for additional information is in response to a preliminary review
The requested information should be received by this Office prior to May 17, 2004, or the application will
be returned as incomplete The return of a project will necessitate resubmittal of all required items,
including the application fee
If you need additional time to submit the information please mail or fax your request for a time
extension to the Division at the address and fax number at the bottom of this Ietter The request must
indicate the date by which you expect to submit the required information The DiNision is allowed 90
da-ts from the receipt of a completed application to issue the permit
The construction of any impervious surfaces, other than a construction entrance under an
approved Sedimentation Erosion Control Plan, is a violation of NCGS 143-215 1 and is subject to
enforcement action pursuant to NCGS 143-215 5A
Please reference the State assigned project number on all correspondence Any original
documents that need to be revised have been sent to the engineer or agent All original documents must be
returned or new originals must be provided Copies are not acceptable If you ha,.e any questions
concerning this matter please feel free to call me at [phone]
Sincerely,
Laurie Munn
Environmental Engineer
RSS/ Ism S1WQSISTORMWATIADDINFO120041031133 may04 doc
cc Laurie Munn
Steve Greer
Kenneth L Clark, P E
Enclosures

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* 50' For SA Class Waters
11 With h as reqtilred to provide
non-erosJve flow
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Stream
PLAN SI:C'rfON A -A

FILE MODE
— 605 MEMORYTX
* * * COMMUNICATION RESULT REPORT ( MAY 11 2004
OPTION
REASON FOR ERROR
E-1) HANG UP OR LINE FAIL
E-3) NO ANSWER
ADDRESS (GROUP)
---
B-9104571095
P 1
B 53AM )
TTI NCDENR WIRO
RESULT PAGE
-------------------------
OK P 6/6
E-2) BUSY
E-4) NO FACSIMILE CONNECTION
Mate of forth Carolina
Department of Environment and Natural Resources
Wilmington Regional Office
Michael F Easley, Governor William G. Ross Jr, Secretary
FAX COVER SHEET
Date: O a4
Tot
Co:
FAX #:C61 l0 Li b`3- ` 10q T-
REMARKS: 'P1P&ze'
No. Of Pages: _
From. yn ZA- r i n
FAX#: [phone]
N
127 Cardinal Drive Extension, Wilmlggton, N C. 29405-3945 Tslephorie [phone] Fax [phone]
An Equal Opportunky A[firmolive Athon Employer

State of North Carolina
Department of Environment and Natural Resources
Wilmington Regional Office
Michael F Easley, Governor William G Ross Jr, Secretary
FAX COVER SHEET
Date:C)/0LI
To:
CO:
FAX #: C0 /0 LIT--" '�-
REMARKS: PI2Q42
No. Of Pages:
From: t,LAA-JU VIq U-rn n
CO: _Ou7Ca_
FAX#: [phone]
�I
q
127 Cardinal Drive Extension, Wilmington, N C 28405-3845 Telephone [phone] Fgx [phone]
An Equal Opportunity Affirmative Action Employer

EB ENGLISH 4APRa9zoo�BUILDERS
E
4705-106 Southport -Supply Highway
Southport, North Carolina 28461
Mr Rich Shiver
Division of Water Quality
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Storm Water Permit No. Sw8 031133
Mr Rich Shiver,
As specified, and condoned by due notification of this violation, English Builders,
Inc is formally requesting a remission or mitigation for the charges of failing to apply for
or secure a permit required by NCGS 143-215 1
I want to start by issuing a background to the 3 1-acre site that was permitted for
storm water permit in 1999 A partner and I purchased this tract of land in 1998 as
MIK_B LLC and proceeded to develop a plan for site development We contracted with
Klien Engineering to design and apply for NC Storm Water Permit and Erosion Control
Permit In Dec of 1998 we were issued an erosion control permit At that point we
proceeded to clear the property and install erosion control devises I believe in Feb we
were issued our storm water permit for the 3 1 acres We then began to construction of
the storm water system, that consisted of dig the pond and installing the overflow system
of the pond
Sometime in April or May we were approached by an agent for C-3 Development
(Gordon Lovingood) to purchase a portion of or property for a Hampton Inn At that
time we stopped all construction at the site After a sales contract was settled upon C-3
Development developed there site plan for the motel and parking Their engineer Tripp
Engineering of Wilmington contacted me about modifying our permit ( MIK-B LLC ) by
our agreement of the sales contract that we ( MIK-B LLC ) would allow a modification of
our permit for their project This is where I become dismayed at the events that took
place
1) At the time C-3 applied for a modification of our permit, MIK-B LLC still
owned the entire 3 1 acre tact of Iand
2) C-3 misrepresented the fact that they were the owners of the land and with the
modification the permit was placed in C-3's name The property exchanging
ownership from MIK-B LLC to C-3 did not take place till after the
modification was in place
3) Charles at Tripp Engineering to authorize the modification of MIK-B LLC's
permit for C-3's development plans contacted me I no way was I informed

that this permit would not still be in the name of MIK-B LLC I was also
assured that the remaining impervious surface was still dedicated to the
remainder of the original tract
4) When we went to modify the permit for the remainder of the site we found
that the permit had been taken out of our name Instead of raising a stink about
the permit being taken out of our name we proceeded in the manner that is of
record at this time
S) I contacted C-3 to inform Gordon of our plans to connect to the storm water
system He then raised the issue of us tying into the rentxon pond He said if he
found that our agreements didn't allow this he would get back with me I tried
to call Gordon several times and with no response I assumed that he found
that we did have the right to tie into the storm water system and it was a dead
issue
Steve Geer project manager for Rob Armstrong and myself meet with Linda
Lewis in her office Friday March 20h to go over our position and our plan to rectify this
issue New plans for storm water will be applied for this week using the fast tract method
to let our project move along and expedite bringing our site in to compliance to NC
Standards and your office
Thank you for the opportunity to present our side of the case, as we perceive it
We hope that this will give you a little insight as to how we perceive we inadvertently
began construction and will give some consideration in our behalf, as we perceived we
were acting in the outmost professional capacity
Sincerely,
E Bryan English
Member / Manager
MIK-B LLC

Land Management Group, Inc.
Environmental Consultants
Post Office Box 2522
Wilmington, North Carolina 28402
Telephone: [phone]
Mann Office
Sus to 15
Downey Branch Office Park
3805 Vrz9htsvz12e Avenue
Wilmington, NC 28403
Apnl 5, 2004
P O Box 1120
504 Croatan
Street
Manteo, NC 27954
Phone.
252-4 73-
3400
Bnan English
4705 Southport Supply Rd
Southport, NC 28461
Reference Soils evaluation for the Old Georgetown Center stormwater project, Southport, Brunswick
County, North Carolina
Dear Mr English,
On March 29, 2004, Land Management Group, Inc completed the soil charactenzation for a proposed
stromwater infiltration basin serving the above -mentioned tract totaling approximately 0 92 acres, located
off Southport Supply Road The proposed area contains both fill material and natural soils Three bonngs
were made within 20' of the road nght-of-way of Southport Supply Road and at the edge of the proposed
parking lot Bonngs were located at a distance of 75', 115', and 150' off the northwest property corner
The boring located 75' off the property cornier contained loamy fine sand/fine sandy loam textured natural
soils At this location the seasonal high water table was 60" and the infiltration ranges from 3 in/hr to 4
in/hr The other two borings contained coarse textured sandy clay loam fill matenal to depths of
approximately 40" Because of this finer textured soils and the corresponding slow infiltration rate of
approximately 0 5 in/hr, it is recommended the proposed basin bottom be placed to a depth of at least 40"
The infiltration rates of the underlying soil is approximately 1 m/hr The seasonal high water table in
these other two locations is greater than 65"
Please do not hesitate to contact me at [phone] or [phone] if you have any questions
Sincerely
3 Tom Gulley
cc Steve Greer

bk�

Lightweight Concrete and
Aggregates
Thomas A Holm,
Authorized Reprint from Standard Technical Publication 169C
Copyright 1994 American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103
PREFACE
Lightweight concrete and aggregates were first discussed
by R E Davis and J Kelly in the 1956 edition of
ASTM STP 169 The ASTM STP 169A and ASTM STP 169B
editions were authored by D W Lewis The general presentation
of this paper is similar to earlier chapters, however,
additional information on elastic properties of
lightweight aggregates, as well as strength making, durability,
and placement characteristics of lightweight concrete
is included to reflect the current state of the art
This edition also includes new discussions relative to the
contact zone and internal curing as well as revisions to
ASTM methods for calculating the equilibrium density of
structural lightweight concrete adopted by ASTM since
the publication of ASTM STP 1698 in 1978
CLASSIFICATION OF LIGHTWEIGHT
AGGREGATES AND LIGHTWEIGHT
AGGREGATE CONCRETES
ASTM Standards provide requirements for lightweight
aggregates that are used in structural masonry units and
insulating types of concrete Structural and insulating
lightweight aggregate concretes are broadly divided into
three groups based upon their use and physical properties
Unit weight, thermal conductivity and compressive
strength ranges normally associated with each class of
concrete are summarized in (Table 1)
This chapter addresses concretes where weight reduction
is achieved through the use of lightweight aggregates
and does not include cellular or foam concrete, where
lighter weight is developed primarily by inclusion of large
amounts of air or gas through foaming -type agents Nofines
concretes with very large, unfilled interstitial voids
produced with aggregate content deficient in fine aggregates
are also excluded from this review, which restricts
discussion to the predominant forms of lightweight aggregate
concretes based upon inorganic lightweight aggregates
Vice president of Engineering, Solrte Corporation, Richmond,
VA 23261
STRUCTURAL -GRADE LIGHTWEIGHT
AGGREGATE AND STRUCTURAL
LIGHTWEIGHT AGGREGATE CONCRETE
Structural -grade lightweight concretes generally contain
aggregates made from pyroprocessed shales, clays,

slates, expanded slags, expanded fly ash, and those nuned
from natural porous volcanic sources Minimum compressive
strength of structural -grade lightweight aggregate
concrete has, in effect, been jointly established by the
ASTM Specification for Lightweight Aggregates for Structural
Concrete (C 330) and the Standard Building Code
for Reinforced Concrete (ACI 318) [11 which requires that
"Structural concrete made with lightweight aggregate, the
air-dned unit weight at 28 days is usually in the range of
1440 to 1850 kg/nb(90 to 115 lb/ft,) and the compressive
strength is more than 17 2 MPa (2500 psi) " This is a
definition, not a specification and project requirements
may permit equilibrium unit weights up to 1900 kg/m,
(120 lb/fb) Although structural concrete with equilibrium
unit weights from 1450 to 1920 kg/rib (90 to 120 lb/ft,)
are often used, most lightweight aggregate concrete used
in structures have equilibrium unit weights between 1600
to 1760 kg/m, (100 and 110 lb/ft,)
Structural -grade Iightweight aggregates are produced
in manufacturing plants from raw materials including
suitable shales, clays, slates, fly ashes, or blast furnace
slags Naturally occurring lightweight aggregates are
nuned from volcanic deposits that include pumice and
scoria types Pyroprocessmg methods include the rotary
kiln process (a long, slowly rotating, nearly horizontal
cylinder lined with refractory materials similar to cement
kilns), the sintering process wherein a bed of raw materials
including fuel is carried by a traveling grate under ignition
hoods, and the rapid agitation of molten slag with controlled
amounts of air or water No single description of
raw material processing is all-inclusive and the reader is
urged to consult local lightweight aggregate manufacturers
for physical and mechanical properties of lightweight
aggregates and the concrete made with them
Increased usage of processed lightweight aggregates is
evidence of environmentally sound planning, as these
products utilize materials with limited structural applications
in their natural state, thus mmirruzmg construction
industry demands on finite resources of natural sands,
stones, and gravels
ASTM C 330 requires fine lightweight aggregates used
in the production of structural lightweight concrete to be
properly graded, with 85 to 100% passing the 4 75 mm
HOLM ON LIGHTWEIGHT CONCRETE AND AGGREGATES 523
TABLE 1—Lightweight Aggregate (LWA) Concrete Classified According to Use and Physical Properties.
Type of Lightweight Typical Range of
Class of Lightweight Aggregate used in Lightweight Concrete Typical Range of Typical Range of
Aggregate Concrete Concrete Unit Weight Compressive Strength Thermal Conductivities
Structural Structural -grade (1440 to 1840) (>17) (>2500) not specified in C 330
LWA C 330 90 to 115 air dry
Structural/ Either structural C 330 (800 to 1440) (3 4 to 17) (500 to 2500) C 332 from (0 22) (l 50)
Insulating or insulating C 332 (50 to 90) air dry to (0 43) (3 00) oven
or a combination dry
Insulating
of C 330 and C 332
Insulating -grade LWA (240 to 800) (0 7 to 3 4) 100 to 500 C 332 from (0 065) (0 45)

C 332 (15 to 50) oven dry to (0 22) (1 50) oven
dry
Unit weights are in (kglm,) (lb/ft,), compressive strengths in (MPa) (psi), and thermal conductivity in (W1m - °K) (Btu • in A
°F)
(3/16 in ) screen with a dry loose bulk density less than 1120
kg/rrb (70 lb/fh) Four coarse aggregate gradations are provided
for use in structural lightweight concrete with maximum
dry loose bulk density limited to 880 kg/m3(55 lb/
fb) Combined fine and coarse aggregate formulations
must not exceed a maximum dry loose unit weight of 1040
kg/m, (65 Ib/%) Tests are conducted in accordance with
ASTM Test Method for Unit Weight and Voids in Aggregate
(C 29) using the shoveling procedure
INSULATING -GRADE LIGHTWEIGHT
AGGREGATES AND INSULATING
LIGHTWEIGHT CONCRETES
Very light nonstructural concretes, employed primarily
for high thermal resistance, incorporate low -density lowstrength
aggregates such as vermiculite and perlite With
low unit weights, seldom exceeding 800 kg/m,(50 lb/ft3),
thermal resistance is high These concretes are not
intended to be exposed to the weather and generally have
a compressive strength range from about 0 69 to 6 89 MPa
(100 to 500 psi)
ASTM Specification for Lightweight Aggregates for
Insulating Concrete (C 332) limits thermal conductivity
values for insulating concretes to a maximum of 0 22 W/
m-K (1 50 Btu - in 2 /h - ftz°F) for concrete having an
oven -dry density of 800 kg/m, (50 lb/fti) or less, and to
0 43 W/m G K (3 0 Btu - in - /h 2 ffi°F) for those weighing
up to 1440 kg/m,(90 lb/%) Lighter concretes are those
made with Group I aggregates (perlites and vermiculite),
while higher unit weights result from the use of Group II
aggregates (expanded shales, expanded slags and natural
lightweight aggregates)
Thermal conductivity values may be determined in
accordance with ASTM Test Method for Steady -State
Thermal Performance of Building Assemblies by Means
of a Guarded Hot Box (C 236) and ASTM Test Method
for Steady -State Heat Flux Measurements and Thermal
Transmission Properties by Means of the Guarded -Hot -
Plate Apparatus (C 177) Oven -dried specimens are used
for both thermal conductivity and unit weight tests on
the insulating concretes Moisture content of insulating
materials directly affects both the thermal conductivtty
and unit weight, but to varying degrees A I % increase in
moisture content will increase unit weight by an equivalent
1 % but may increase thermal conductivity by as much
as 5 to 9% [2] Use of oven -dried specimens provides an
arbitrary basis for comparison but clearly does not duplicate
in-service applications The controlled test conditions
serve to permit classification of materials and to provide
a standardized reference environment
STRUCTURAL/INSULATING
LIGHTWEIGHT AGGREGATE
CONCRETES

Widespread industrial applications that call for "fill"
concretes require modest compressive strengths with densities
intermediate between the structural- and msulatinggrade
concretes These concretes may be produced with
high air mixes with structural -grade lightweight aggregate,
with sanded insulating lightweight aggregate mixes,
or with formulations incorporating both structural- and
insulating -grade lightweight aggregates Compressive
strengths from 3 4 to 17 MPa (500 to 2500 psi) are not
uncommon with thermal resistance less than concretes
containing only insulating -grade lightweight aggregate
LIGHTWEIGHT AGGREGATE
PROPERTIES
Internal Structure of Lightweight Aggregates
Lightweight aggregates develop low particle specific
gravity because of the cellular pore system Cellular structure
within the particles is normally developed at high
temperatures by formation of gases due to the reaction
of heat on certain raw material constituents coincident
with incipient fusion causing gas expansion to be trapped
in the viscous, pyroplastic mass Strong, durable lightweight
aggregates are produced when small -size, well -distributed,
noninterconnected pores are enveloped in a
continuous, crack free, vitreous phase [3] (Fig 1)
PARTICLE SHAPE AND SURFACE
TEXTURE
Depending on the source and the method of production,
lightweight aggregates exhibit considerable differences in
524 TESTS AND PROPERTIES OF CONCRETE
FIG 1 -Contact zone -structural lightweight concrete from
30-year-old bridge deck, W P Lane Memorial Bridge over the
Chesapeake Bay, Annapolis, Maryland compression strength
24 MPa (3500 psi), density 1680 kglm,(105 lb/ft.)
particle shape and texture Shapes may be cubical,
rounded, angular, or irregular Textures may range from
fine pore, relatively smooth skins to highly irregular surfaces
with large exposed pores Particle shape and surface
texture directly influence workability, coarse -to -fine
aggregate ratio, cement content requirements, and water
demand in concrete mixes, as well as other physical properties
SPECIFIC GRAVITY
The specific gravity of an aggregate is the ratio between
the mass of a quantity of the material and the volume
occupied by the individual particles contained in that sample
This volume includes the pores within the particles
but does not include the voids between the particles In
general, the volume of the particles is determined from the
volume displaced submerged in water when penetration of
water into the particles during the test is limited by previous
saturation Specific gravity of individual particles
depends both on the specific gravity of the poreless vitreous
material and the pore volume within the particles,
and generally increases when particle size decreases The
specific gravity of the pore -free vitreous material may be
determined by pulverizing the lightweight aggregate in a

jar null and then following procedures used for determination
of the specific gravity of cement in the ASTM Test
Method for Density of Hydraulic Cement (C 188)
BULK UNIT WEIGHT OF LIGHTWEIGHT
AGGREGATES
Aggregate bulk unit weight is defined as the ratio of the
mass of a given quantity of material and the total volume
occupied by it This volume includes the voids between
as well as within the particles Unit weight is a function
of particle shape, density, size, gradation, and moisture
content, as well as the method of packing the material
(loose, vibrated, rodded) and varies not only for different
materials, but for different sizes and gradations of a particular
material Table 2 summarizes the maximum unit
weights for lightweight aggregates listed in ASTM C 330,
ASTM Specification for Lightweight Aggregates for Concrete
Masonry Units (C 331), and ASTM C 332 Minimum
unit weights for perlite and vermiculite are also provided
to linut over -expanded, weak particles that would break
down in mixing
Density of insulating concrete is usually determined in
an over -dry condition, using oven -dry weight and dimensions
of specimens associated with to those subjected to
either thermal conductivity or compressive strength tests
Density of insulating concretes made with perlite or vermiculite
aggregates or cellular concretes may range from
240 to 800 kg/rrb (15 to 50 lb/ft.), while those made with
other types of lightweight aggregates are usually in the
range of 800 to I440 kg/nv (50 to 90 lb/ft3)
TOTAL POROSITY
Void content (within particle pores and between particles'
voids) can be determined from measured values of
particle specific gravity and bulk unit weight If, for example,
measurements on a sample of lightweight coarse
aggregate are
2
3
bulk dry loose unit weight, 770 kg/rry (48 lb/fib),
particle specific gravity, 1400 kg/m,, and
specific gravity of poreless vitreous material, 2500
kg/mb,
TABLE 2 —Requirements of ASTM C 330, C331, and C 332 for Dry
Loose Unit Weight of Lightweight Aggregates
Maximum Minimum
Aggregate Unit Weight, Unit Weight,
Size and Group kglm,(lb/ft ,) kg/m,(ib/ft,)
ASTM C 330 AND C 331
fine aggregate
coarse aggregate
combined fine and
coarse aggregate
ASTM C 332
Group I
Perhte
Vermiculite
Group 2
fine aggregate

coarse aggregate
combined fine and
coarse aggregate
(1120)(70)
(880)(55)
(1040)(65)
(196) (12) (120) (7 5)
(160) (10) (88) (5 5)
(1120)(70)
(880)(55)
(1040)(65)
HOLM ON LIGHTWEIGHT CONCRETE AND AGGREGATES 525
then the fractional pore volume of an individual particle is
2500-1400
= 0 44 2500
and the fractional interstitial void volume (between particles)
is
1
11400-7700
rm
For this example, total porosity (pores and voids) would
then equal
[0 45 + (0 44 X 0 55)] m 0 69
GRADATION
Gradation requirements are generally smular to those
provided for normal -weight aggregate with the exception
that lightweight aggregate particle size distribution permits
a higher weight through smaller sieves This modification
recognizes the increase in specific gravity typical
for the smaller particles of most lightweight aggregates,
and that while standards are established by weights passing
each sieve size, ideal formulations are developed
through volumetric considerations
An exception to the procedures of ASTM Method for
Sieve Analysis of Fine and Coarse Aggregates (C 136)
requires reduction of the weight of fine aggregate sample
tested according to the lightweight aggregate's unit weight,
and sieving time not to exceed 5 min
Producers of structural Iightweight aggregate normally
stock materials in several standard size formulations of
coarse, mtermediate, and fine aggregate By combining
size fractions or by replacing some or all of the fine fraction
with a normal -weight sand, a wide range of concrete
unit weights may be obtained The aggregate producer is
the best source of information for the proper aggregate
combinations to meet fresh unit weight specifications and
equilibrium unit weights for dead load design considerations
Normal -weight sand replacement will typically increase
unit weight from about 80 to more than 160 kg/rm (5 to
10 lb/%) Using increasing amounts of cement to obtain
high strengths above 35 MPa (5000 psi) concrete will
increase air dry density from 32 to 96 kg/m, (2 to 6 lb/fli)
ABSORPTION CHARACTERISTICS
Due to their cellular structure, lightweight aggregates
absorb more water than their normal -weight aggregate
counterparts Based upon a 24-h absorption test, conducted
in accordance with the procedures of ASTM Test

Method for Specific Gravity and Absorption of Coarse
Aggregate (C 127) and ASTM Test Method for Specific
Gravity and Absorption of Fine Aggregate (C 128), structural -
grade lightweight aggregates will absorb from 5 to
more than 25% by weight of dry aggregate By contrast,
normal -weight aggregates generally absorb less than 20/0
of moisture The important difference in measurements
of stockpile moisture contents is that with lightweight
aggregates the moisture is largely absorbed into the interior
of the particles whereas in normal -weight aggregates
it is primarily surface adsorption Recognition of this
essential difference is important in mix proportioning,
batchmg, and control Rate of absorption of lightweight
aggregates is dependent on the characteristics of pore size,
connection, and distribution, particularly those close to
the surface Internally absorbed water within the particle
is not immediately available for chemical interaction with
cement as mixing water, but extremely beneficial in maintaining
longer periods of curing essential to improvements
in the aggregate/matrix contact zone Internal curing will
also bring about reduction of permeability by extending
the period in which additional products of hydration are
formed in the pores and capillaries of the binder
MODULUS OF ELASTICITY OF
LIGHTWEIGHT AGGREGATE PARTICLES
The modulus of elasticity of concrete is a function of
the moduli of its constituents Concrete may be considered
as a two-phase material consisting of coarse aggregate
inclusions within a continuous "mortar" fraction that
includes cement, water, entrained air, and fine aggregate
Dynamic measurements made on aggregates alone have
shown a relationship corresponding to the function E =
0 008 pi, where E is the dynamic modulus of elasticity of
the particle in MPa and p is the dry mean specific gravity
in kg/m, [4] (Fig 2) Dynamic moduli for usual expanded
aggregates have a range of 10 to 16 GPa (1 45 to 2 3 X
10.psi), whereas the range for strong ordinary aggregates
s
FIG 2-Relationship between mean particle density and the
mean dynamic modulus of elasticity for the particles of lightweight
aggregate [12]
526 TESTS AND PROPERTIES OF CONCRETE
is approximately 30 GPa (4 35 X 106psi) to 100 GPa (14 5
x 106 psi)
PROPERTIES AND PRODUCTION OF
LIGHTWEIGHT AGGREGATE CONCRETE
Comprehensive reports detailing the properties of lightweight
concretes and lightweight aggregates have been
published by Shideler (5], Reichard (6], Helm [7], Carlson
[8], and Valore [9,10) The first three deal with structuralgrade
concretes, Carlson reported on lightweight aggregate
for concrete masonry units, and Valore covered both
structural and insulating concretes In most instances,

test procedures for measuring properties of lightweight
concretes were the same as commonly used for normalweight
concretes In limited cases, special test procedures
particularly suited to measure lightweight concrete characteristics
were developed
PROPORTIONING
In general, proportioning rules and techniques used for
ordinary concrete mixes apply to lightweight concrete
with added attention given to concrete unit weight and
the influence of the water absorption charactenstics of
the lightweight aggregate [11] Most structural -grade
lightweight concretes are proportioned by absolute volume
methods in which the fresh concrete produced is
considered equal to the sum of the absolute volumes of
cement, aggregates, net water, and entrained air Proportioning
by this method requires the determination of
absorbed and adsorbed moisture contents and the as -used
specific gravity of the separate sizes of aggregates A widely
used alternative to the absolute volume procedures is to
proportion lightweight concrete mixes by the damp loose
volume method [I 1 ]
Specifications for structural -grade lightweight concrete
usually require nummum values for compressive and tensile
splitting strength, maximum limitations on slump,
specified ranges of air content, and, finally, a linutation
on maximum fresh unit weight Reduction of concretes'
high density leads to improved structural efficiency and
is, therefore, an important consideration in proporttamng
lightweight concrete mixtures While this property
depends pnmarily on the specific gravity of the lightweight
aggregates, it is also influenced to a lesser degree by
cement, water, and air contents, and proportions of
coarse -to -fine aggregate
When lightweight aggregates contain levels of absorbed
moisture greater than that developed after a one -day
immersion, the rate of further absorption will be very low
and for all practical purposes lightweight concrete may
be batched, placed, and finished with the same facility as
their normal -weight concrete counterparts Under these
conditions water/cement (w/c) ratios, while not normally
specified, may be established with precision comparable
to concretes containing normal -weight aggregates Water
absorbed within the lightweight aggregate prior to mixing
is not available for calculating the volume of cement paste
at the time of setting This absorbed water is available,
however, for continued cement hydration after external
curing has ended The general practice is to proportion
the mix for a particular lightweight aggregate on the basis
of a cement content at a given slump
As with normal -weight concrete, air entrainment in
lightweight concrete significantly improves durability and
resistance to scaling In concretes made with angular lightweight
aggregates, it is also an effective means of improving
workability of otherwise harsh mixtures With
moderate air contents, bleeding and segregation are
reduced and mixing water requirements lowered while

maintaining optimum workability Because of the elastic
compatibility of the lightweight aggregate and cementitious
binder phases, strength reduction penalties due to
high air contents will be lower for structural lightweight
concrete than for normal -weight concretes [12] Recommended
ranges of total air content of usual structural
lightweight concretes are shown in Table 3
Air content of lightweight aggregate concretes is determined
in accordance with the procedures of ASTM Test
Method for Air Content of Freshly Mixed Concrete by the
Volumetnc Method (C 173) Volumetric measurements
assure reliable results while pressure meters will provide
erratic data due to the influence of aggregate porosity
Air contents higher than are required for durability considerations
are frequently developed for high thermal
resistance, or for lowering unit weight of semi -structural
"fill" concrete, with reduced compressive strength as a
natural consequence Use of water reducers, retarders,
and superplasticizers will result in improved lightweight
concrete characteristics in a manner similar to that
of normal -weight concretes, however, superplasticizers,
while effective, will increase the density of lightweight as
well as other concretes
MIXING, PLACING, FINISHING, AND
CURING
When properly proportioned, structural lightweight
concrete can be delivered and placed with the same facility
as ordinary concretes The most important consideration
in handling any type of concrete is to avoid separation of
coarse aggregate from the mortar fraction Basic principles
required to secure a well -placed lightweight concrete
include
(a) well-proportioned, workable mixes that use a minimum
amount of free water,
(b) equipment capable of expeditiously moving the concrete,
(e) proper consolidation in the forms, and
(d) quality workmanship in finishing
TABLE 3 —Total Air Content for Lightweight Concretes
Maximum Size of Aggregate Air Content, % by volume
(20 mm) (3/4 in ) 4 to 8
(10 mm) (3/8 in ) 5 to 9
HOLM ON LIGHTWEIGHT CONCRETE AND AGGREGATES 527
Well-proportioned structural lightweight concretes can be
placed and screeded with less physical effort than that
required for ordinary concrete Excessive vibratation
should be avoided, as this practice serves to drive the
heavier mortar fraction down from the surface where it
is required for finishing On completion of final finishing,
curing operations similar to ordinary concrete should
begin as soon as possible Lightweight concretes batched
with aggregates having high absorption carry their own
internal water supply for curing within the aggregate and
as a result are more forgiving to poor curing practices or
unfavorable ambient conditions This "internal curing"
water is transferred from the lightweight aggregate to the

mortar phase as evaporation takes place on the concrete
surface, thus maintaining continuous moisture balance by
replacing moisture essential for an extended continuous
hydration period determined by ambient conditions and
the as -batched lightweight aggregate moisture content
Lightweight aggregates may absorb part of the mixing
water when exposed to increased pumping pressures To
avoid loss of workability, it is essential to raise the presoak
absorption level of lightweight aggregates prior to pumping
Presoaking is best accomplished at the aggregate production
plant where uniform moisture content is achieved
by applying water from spray bars directly to the aggregate
moving on belts This moisture content can be maintained
and supplemented at the concrete plant by stockpile hose
and sprinkler systems
Presoaking will significantly reduce the lightweight
aggregates' rate of absorption, minimizing water transfer
from the mortar fraction that, in turn, causes slump loss
during pumping Higher moisture contents developed during
presoaking will result in increased specific gravity that,
in turn, develops higher fresh concrete unit weight Higher
water content due to presoaking will eventually diffuse
out of the concrete, developing a longer period of internal
curing as well as a larger differential between fresh and
equilibrium unit weight than that associated with lightweight
concretes placed with lower moisture contents
Aggregate suppliers should be consulted for r ux design
recommendations necessary for consistent pumpabiltty
LABORATORY AND FIELD CONTROL
Changes in lightweight aggregate moisture content, gradation,
or specific gravity as well as usual job site variation
in entrained air suggest frequent checks of the fresh concrete
to facilitate adjustments necessary for consistent
concrete characteristics Standardized field tests for consistency,
fresh unit weight, and entrained -air content
should be employed to verify conformance of field concretes
with design mixes and the project specification
Sampling should be conducted in accordance with ASTM
Practice for Sampling Freshly Mixed Concrete (C 172)
and ASTM Test Method for Air Content of Freshly Mixed
Concrete by the Volumetric Method (C 173) The ASTM
Test Method for Unit Weight of Structural Lightweight
Concrete (C 567) describes methods for calculating the mservice,
equilibrium unit weight of structural lightweight
concrete In general, when variations in fresh density
exceed ±2%, an adjustment in batch weights may be
required to restore specified concrete properties To avoid
adverse effects on durability, strength, and workability,
air content should not vary more than ±1 5% from specified
values
DENSITY OF STRUCTURAL
LIGHTWEIGHT CONCRETE
Although there are numerous structural applications
of all lightweight concretes (coarse and fine lightweight
aggregate), usual commercial practice in North America

is to design sanded lightweight concretes where part or
all of the fine aggregates used is natural sand Long -span
bridges using concretes with three-way blends (coarse and
fine lightweight aggregates and small supplemental natural
sand volumes) have provided long-term durability and
structural efficiency (density/strength ratios) [14] Earliest
research reports [5, 6, 15, 16] compared all lightweight concretes
with "reference" normal -weight concrete while later
studies reported in Refs 13, 17-19 supplemented the early
findings with data based upon sanded lightweight concretes
The fresh unit weight of lightweight aggregate concretes
is a function of mix proportions, air contents, water
demand, and the specific gravity and moisture content of
the lightweight aggregate Decrease in density of exposed
concrete is due to moisture loss that, in turn, is a function
of ambient conditions and surface area/volume ratio of the
member Design professionals should specify a maximum
fresh density for lightweight concrete, as limits of acceptability
should be controlled at time of placement
Dead loads used for design should be based upon equilibrium
density that, for most conditions and members,
may be assumed to be reached after 90 days Extensive
tests conducted dunng North American durability studies
demonstrated that despite wide initial variations of aggregate
moisture content, equilibrium density was found to
be 50 kg/nu (3 1 lb/fig) above oven -dry density (Fig 3)
European recommendations for in-service density are
similar [4]
When weights and moisture contents of all the constituents
of the batch of concrete are known, an approximate
calculated equilibrium density may be determined
according to ASTM C 567 from the following equation
E=0+50kg/nb(E=0+3lb/ft3)(1)
where
0= A + 1 2W,
E = calculated equilibrium unit weight, kg/nb (lb/fh),
0 = approximate oven -dry weight, kg/m3 (lb/fb),
A = weight of dry aggregates in batch, kg (lb),
W = weight of cement in batch, kg (lb), and
12 = weight of hydrated water of hydration (estimated at
20% by weight of cement)
COMPRESSIVE STRENGTH
Compressive strength test procedures for structural
lightweight aggregate concretes are similar to those for
528 TESTS AND PROPERTIES OF CONCRETE
TIME OF DRYING {DAYS) -
FRESH DENSITY Specified for field control (unit weight bucket) Measurements
on 0 X 12 (150 X 300 mm) cylinder* will average 2 50 (40kglm.) higher than field
measurements on 5 pd ( 014 kgm.) unit weight bucket
EQUILIBRIUM DENSITY Typically Spef (50 kglm.) greater than OVEN DRY
FIG 3-Concrete density versus time of drying for structural
lightweight concrete
normal -weight concretes with the exception of the 21-day
laboratory air 23°C (73 4°F) and 50% relative humidity
drying period required by the procedures of ASTM Test
Method for Splitting Tensile Strength of Cylindrical Concrete
Specimens (C 496) and ASTM C 567 While most
structural -grade lightweight aggregates are capable of producing

concretes with compressive strengths in excess of
35 MPa (5000 psi), a limited number of lightweight aggregates
can be used in concretes that develop cylinder
strengths from 48-69 MPa (7000 to 10000 psi)
While compressive strengths of 21 to 35 MPa (3000
to 5000 psi) are common for cast-m-place structural lightweight
concretes, 41 MPa (7000 psi) strengths are
presently being specified for offshore applications Light
weight aggregate concrete will demonstrate a strength
"ceiling" where further additions of cementitious materials
will not significantly raise the maximum attainable
strength Strength ceilings that differ for each lightweight
aggregate source are the result of pore size and distribution
as well as the strength characteristics of the porefree
vitreous material surrounding the pores The strength
ceiling of a particular lightweight aggregate may be considerably
increased by reduction of the top size in a particular
grading formulation
Compressive strength tests of lightweight insulating
concrete having oven -dry unit weights not exceeding 800
kg/m, (50 lb/fh) are conducted in accordance with ASTM
Test Method for Compressive Strength of Lightweight
Insulating Concrete (C 495) on 75 X 150 mm (3 X 6 in)
cylinders Twenty-five days after molding, the specimens
are oven-dned at 60 f 2 8°C (140 ± 5°F) for three days,
cooled to room temperature, and tested for compressive
strength at 28 days
ASTM Methods of Securing, Preparing, and Testing
Specimens from Hardened Lightweight Insulating Concrete
for Compressive Strength (C 513) provides procedures
for the determination of the compressive strength
of cube specimens from hardened, field lightweight insulating
concretes
TENSILE STRENGTH
Shear, torsion, anchorage, bond strengths, and crack
resistance are related to tensile strength that is, in turn,
dependent upon tensile strength of the coarse aggregate
and mortar phases and the degree to which the two phases
are securely bonded Traditionally, tensile strength has
been defined as a function of compressive strength, but
this is known to be only a first approximation that does not
reflect aggregate particle strength, surface characteristics,
nor the concrete's moisture content and distribution The
splitting tensile strength, as determined by ASTM C 496,
is used throughout North America as a simple, practical
design criteria that is known to be a more reliable indicator
of tensile -related properties than beam flexural tests Splitting
tests are conducted by applying diametrically opposite
compressive line loads to a concrete cylinder laid
horizontally in a testing machine A mrmmurn tensile splitting
strength of 2 0 MPa (290 psi) is a requirement for
structural -grade lightweight aggregates confornung to the
requirements of ASTM C 330
Tests have shown that diagonal tensile strengths of
beams and slabs correlate closely with the concrete splitting
strengths [20, 21 ] As tensile splitting results vary for

different combinations of materials, the specifier should
consult with the aggregate suppliers for laboratory -developed
splitting strength data Special tensile strength test
data should be developed prior to the start of unusual
projects where development of early -age tensile -related
handling forces occur as in precast or tilt -up members
Tensile strength tests on structural lightweight concrete
specimens that undergo some drying correlate better with
the behavior of concrete in actual structures Moisture
loss progressing slowly into the interior of concrete members
will result in the development of outer envelope tensile
stresses that balance the compressive stresses in the
still -moist interior zones ASTM C 496 requires a sevenday
moist and 21-day laboratory air drying at 23°C (73 47)
and 50%0 relative humidity prior to conducting splitting
tests Structural -lightweight -concrete splitting tensile
strengths vary from approximately 75 to 100% of normalweight
concretes of equal compressive strength Replacing
lightweight fine aggregate with normal -weight fines will
normally increase tensile strength
ELASTIC PROPERTIES
The modulus of elasticity of concrete is a function of
the modulus of each constituent (border matrix, expanded
and normal density aggregates) and their relative mix proportion
The elastic modulus of normal -density concretes
is higher because the moduli of the natural aggregate particles
(and parent rock formations) are greater than the
moduli of lightweight aggregate particles For practical
design conditions, the modulus of elasticity of concretes
with densities between 1400 to 2500 kg/nb (90 to 155 lb/
HOLM ON LIGHTWEIGHT CONCRETE AND AGGREGATES 529
ft,) and within normal strength ranges may be assumed
to follow the formula [1,4]
(2)
where
E = denotes the secant modulus in psi (MPa),
P = the density in kg/m3(lb/ft,), and
f = the compressive strength in MPa (psi) of a 150 by
300 min (6 by 12 in) cylinder (100 mm cube)
This or any other formula should be considered as only
a first approximation, as the modulus is significantly
affected (t 25%) by moisture, aggregate type, and other
variables The formula clearly overestimates the modulus
for high -strength lightweight concretes where limiting values
are determined by the modulus of the lightweight
aggregate When design conditions require accurate elastic
modulus data, laboratory tests should be conducted
on specific concretes proposed for the project according
to procedures of ASTM Test Method for Static Modulus
of Elasticity and Poisson's Ratio of Concrete in Compression
(C 469)
Tests to determine Poisson's ratio by the static method
for lightweight and sand -and -gravel concrete gave values
that varied between 0 15 and 0 25 and averaged 0 20
Dynamic tests yielded slightly higher values [6] A value

of 0 20 may be assumed for design purposes for both types
of concretes
SHRINKAGE
As with ordinary concretes, shrinkage of structural lightweight
concretes is principally determined by
(a) shrinkage characteristics of the cement paste fraction,
(b) internal restraint provided by the aggregate fraction,
(c) the relative absolute volume fractions occupied by the
shrinkage medium (cement paste fraction) and the
restraining skeletal structure (aggregate fraction), and
(d) humidity and temperature environments
Aggregate characteristics influence cementitious binder
quantities (the shrinking fraction) necessary to produce
a required strength at a given slump Particle strength,
shape, and gradation influence water demand and directly
deterrrune the fractional volume and quality of the cement
paste necessary to meet specified strength levels Once
that interaction has been established, it is the rigidity of
the aggregate fraction that restrains shrinkage of the
cement paste When structural lightweight aggregate concretes
are proportioned with cementitious bmder amounts
similar to that required for normal aggregate concretes,
the shrinkage of lightweight concrete is generally, but not
always, slightly greater than that of ordinary concrete due
to the lower aggregate stiffness The time rate of shrinkage
strain development in structural lightweight concrete is
slower, and the time required to reach a plateau of equilibrium
is longer when the as -batched, lightweight -aggregate
absorbed moisture is high Maximum shrinkage strains
of high -strength lightweight concretes are slightly greater
than high -strength normal -weight concretes containing
similar binder content [22]
ASTM C 330 lumts shrinkage of structural lightweight
concretes to less than 0 07% after 28 days of drying in a
curing cabinet maintained at 37 8°C ( 100°F) at a relative
humidity of 32% Concrete mixtures used in the specimen
prisms are prepared with a cement content of 335 kg/nb
(564 lblyd3) with water contents necessary to produce a
slump of 50 to 100 mm (2 to 4 in ) and air content of 6
�: 10% Specimens are removed from the molds at one day,
and moisture cured until seven days at which time the
accelerated drying is initiated
Shrinkage of block concrete is limited to O 10% when
determined in accordance with procedures outlined in
ASTM C 331 The ASTM Test Method for Length Change
of Hardened Hydraulic Cement Mortar and Concrete (C
157) is followed using fixed proportions of one part cement
to six parts aggregate by dry loose volumes, with sufficient
water to produce a slump of 50 to 76 min (2 to 3 in )
Initial length measurements are made after seven days
moist storage with final shrinkage measurements at the
age of 100 days after storage in laboratory air at 23°C
(73 4°F) and 50% relative humidity
CREEP
Time -related increases in concrete strain due to sustained
stress can be measured according to procedures of

ASTM Test Method for Creep of Concrete in Compression
(C 512) Creep and shrinkage characteristics on any concrete
type are principally influenced by aggregate characteristics,
water and cement content (paste volume
fraction), age at time of loading, type of curing, and
applied stress -to -strength ratio Other second -level variables
also influence creep and shrinkage but to a lesser
degree As creep and shrinkage strains will cause increase
in long-time deflections, loss of prestress, reduction in
stress concentration, and changes in camber, it is essential
for design engineers to have an accurate assessment of
these time -related characteristics as a necessary design
input ACI Committee 213 [l 1] demonstrates wide envelopes
of one-year specific creep values for low -strength
all -lightweight, normally cured concretes Test results for
higher -strength, steam -cured sanded -lightweight concretes
have a range of values that narrows significantly and
closely envelopes the performance of the normal -weight
"reference" concrete These values are principally based
upon the results of the comprehensive testing program of
Shideler [5] Long-term investigations by Troxell [23] on
normal -weight concretes report similar wide envelopes of
results for differing natural aggregate types so comparisons
with "reference" concretes should be based upon data
specific to the concretes considered
Additional large-scale creep testing programs are reported
in Refs 7 and 19, and Valore [10] has provided a
comprehensive report that also includes European data
on structural as well as insulating -grade lightweight concretes
DURABILITY
Numerous accelerated freeze/thaw testing programs
conducted on structural lightweight concrete in North
530 TESTS AND PROPERTIES OF CONCRETE
America [24,25] and in Europe [4] researching the influence
of entrained -air volume, cement content, aggregate
moisture content, specimen drying times, and testing environment
have arrived at smular conclusions air -entrained
lightweight concretes proportioned with high -quality
binder provide satisfactory durability results when tested
under usual laboratory freeze/thaw programs Observations
of the resistance to deterioration in the presence of
deicing salts on mature bridges indicate similar performance
between structural lightweight and normal -weight
concretes [3] Comprehensive investigations into the longterm
weathering performance of bridge decks [26] and
marine structures [27] exposed for many years to severe
environments support the findings of laboratory investigations
and suggest that properly proportioned and placed
lightweight concretes perform equal to or better than normal -
weight concretes
Core samples taken from hulls of 70-year-old lightweight
concrete ships as well as 30- to 40-year-old lightweight
concrete bridges have demonstrated concretes with
high integrity contact zone between aggregate and the
matrix with low levels of microcracking Explanation of
this proven record of high resistance to weathering and

corrosion is due to several physical and chenucal mechanisms
including superior contact zone resistance to microcracking
developed by significantly higher aggregate/
matrix adhesion as well as internal stress reduction due
to elastic matching of coarse aggregate and matrix phases
High ultimate strain capacity is also provided by concretes
with a high strength/modulus ratios The ratio at which
the disruptive dilation of concrete starts is higher for lightweight
concrete than for equal strength normal -weight
concrete A well -dispersed void system provided by the
lightweight fine aggregates may also assist the air entrainment
pore system and serve an absorption function by
reducing salt concentration levels in the matrix phase [27]
Long-term pozzolamc action is provided when the
silica -rich expanded aggregate combines with calcium
hydroxide liberated during cement hydration This will
minimize leaching of soluble compounds and may also
reduce the possibility of sulphate salt disruptive behavior
[28]
It is widely recognized that while ASTM Test Method
for Resistance of Concrete to Rapid Freezing and Thawing
(C 666) provides a useful comparative testing procedure,
there remains an inadequate correlation between accelerated
laboratory test results and the observed behavior of
mature concretes exposed to natural freezing and thawing
The inadequate laboratory/field correlation observed for
normal -weight concrete is compounded when interpreting
results from laboratory tests on structural lightweight concretes
prepared with aggregate moisture contents typical
of commercial operations A proposed modification to
ASTM C 666 [29] suggests that a 14-day air -drying period
prior to the first freezing cycle will improve correlation
between laboratory test data and observed field performance
Durability characteristics of any concrete, both
normal weight and lightweight, are primarily determined
by the protective qualities of the cement paste matrix
It is imperative that permeability characteristics of the
concrete matrix be of high quality in order to protect steel
reinforcing from corrosion, which is clearly the dominant
form of structural deterioration observed in current construction
The matrix protective quality of concretes proportioned
for thermal resistance by using high -air and
low -cement contents will be significantly reduced, Very
low density, non-structural concretes will not provide
resistance to the intrusion of chlorides, carbonation, etc ,
comparable to the long-term satisfactory performance
demonstrated with high -quality, structural -grade lightweight
concretes [29],
For a number of years, field exposure testing programs
have been conducted by the Canadian Department of Minerals,
Energy and Technology (CANMET) on various types
of concretes exposed to a cold marine environment at the
Treat Island Severe Weather Exposure Station maintained
by the U S Army Corps of Engineers at Eastport, Maine
[29) Concrete specimens placed on a mid -tide wharf experience
alternating conditions of seawater immersion followed

by cold air exposure at low tide In typical winters,
the specimens experience about 100 cycles of freezing
and thawing In 1978, a series of prisms were cast using
commercial normal -weight aggregates with various
cement types and including supplementary cementitious
materials Water -to -cement ratios of 0 40, 0 50, and 0 60
were used to produce 28-day compressive strengths of 30,
26 and 24 MPa (4350, 3770, and 3480 psi), respectively
In 1980, these mixes were essentially repeated with the
exception being that the 40 mm ( 1 '/, in ) gravel aggregate
was replaced with a 25 mm (1 in ) expanded -shale lightweight
aggregate Fine aggregates used in both 1978 and
1980 were commercially available natural sands Cement
contents for the serru-lightweight concrete mixtures were
approximately 480, 360 and 240 kg/nb (800, 600, and 400
lb/ydb) that produced compressive strengths of 36,30 and
19 MPa (5220, 4350, and 2755 psi), respectively All specimens
continue to be evaluated annually for ultrasonic
pulse velocity and resonant frequency as well as being
rated visually Ultrasonic pulse velocities are measured
centrally along the long axis of the prisms There were no
significant differences between the structural lightweight
concrete (eight years) and normal -weight concrete (ten
years) after exposure to twice -daily seawater submersion
and approximately 1000 cycles of freezing and thawing
[29)
CHEMICAL REACTION
ACI Committee 201 on Durability of Concrete reports
no documented instance of in-service distress caused by
alkali reactions with lightweight aggregate Mielenz [30]
indicates that although the potential exists for alkali aggregate
reaction with some natural lightweight aggregates
and expanded perlite, the volume change may be accommodated
without necessarily causing structural distress
Granulated blast furnace slag has been shown to be an
effective inhibitor of such reactions [31], and the fine
aggregate fractions of expanded shales, clays, and slates
are known to be pozzolanic and may also serve to inhibit
disruptive expansion Bremner [32] reports that no
evidence of alkali lightweight aggregate reaction was
HOLM ON LIGHTWEIGHT CONCRETE AND AGGREGATES 531
observed in tests conducted on 70-year-old marine and
more than 30-year-old lightweight concrete bridge decks
POPOUTS
Popouts may result from delayed disruptive expansions
caused by the slow hydration of particles of hard -burned
time or magnesia, calcium sulfate, or unstable iron compounds
To test for the presence of these materials, concrete
bars prepared by methods similar to those used for
the shrinkage tests are cured and tested according to the
procedures of ASTM Test Method for Autoclave Expansion
of Portland Cement (C 151) No popouts are permitted by
ASTM C 331 and C 330 since this disruptive expansion
would cause unacceptable aesthetic blemishes on exposed
concrete and masonry

ABRASION RESISTANCE
Abrasion resistance of concrete depends on strength,
hardness, and toughness characteristics of the cement
paste and the aggregates, as well as on the bond between
these two phases Most lightweight aggregates suitable
for structural concretes are composed of solidified glassy
material comparable to quartz on the Moh scale of hardness
However, due to its porous system, the net resistance
to wearing forces maybe less than that of a solid particle of
most natural aggregates Structural -lightweight -concrete
bridge decks that have been subjected to more than 100
million vehicle crossings including truck traffic show
wearing performance similar to that of normal -weight
concretes [33] Limitations are necessary in certain commercial
applications where steel -wheeled industrial vehicles
are used, but such surfaces generally receive specially
prepared surface treatments Hoff [34] reports that specially
developed testing procedures that measured ice
abrasion of concrete exposed to arctic conditions demonstrated
essentially similar performance for lightweight
and normal -weight concretes
BOND STRENGTH AND DEVELOPMENT
LENGTH
Field performance has demonstrated satisfactory performance
for lightweight concrete with respect to bond
and development length Because of the lower particle
strength, lightweight concretes have somewhat lower
bond splitting capacities than normal -weight concrete
Usual North American design practice (ACI 318 Standard
Building Code for Reinforced Concrete) is to dispense with
concepts of bond and require slightly longer embedment
lengths for reinforcement in lightweight concretes than
that required for normal -weight concrete
FIRE RESISTANCE
When tested according to the procedures of ASTM
Method for Fire Tests of Building Construction and Mate -
FIG 4 -Fire endurance (heat transmission) of concrete slabs
as a function of thickness for naturally dried specimens (11]
rials (E 119), structural lightweight aggregate concrete
slabs, walls, and beams have demonstrated greater fire
endurance periods than equivalent thickness members
made with normal -weight aggregates (Fig 4) Superior
performance is due to a combination of lower thermal
conductivity (lower temperature rise on unexposed surfaces),
lower coefficient of thermal expansion (lower
forces developed under restraint), and the inherent thermal
stability developed by aggregates that have been
exposed to temperatures greater than 1093°C (2000°F) during
pyroprocessing
Acknowledgments
The principal sources of information for this chapter
include the Guide for Structural Lightweight Aggregate Concrete
(ACI 213) [11], ACI 318 Building Code Requirements
for Reinforced Concrete [I], the CEB-FIP Manual of
Design and Technology Lightweight Aggregate Concrete
[4], and the Handbook of Structural Concrete [7] References

211 site
Subject: 211 site
From: "Bonkers" <bonkers@mfire com>
Date: Wed, 12 May 2004 09 43 40 -0400
To: "Laurie Munn" <Laurie Munn@ncmatl net>
Laurie,
I hope this will suffice. Ken did his impirical tests, and utilizing that fellas paper, should be
convincing enough to use 50%
Steve
I stopped by and got some pumice yesterday I did a void test
whereby by I determined the volume of water necessary to fill an
empty container I then emptied the container and filled the
container with uncompacted pumice rock I then poured water into
the rock filled container to order to determine the volume of
voids remaining (volume displaced by added water) The percent
voids can then be determined by dividing the second volume (water
needed to fill voids) by the first volume (water needed to fill
empty container) to determine percent voids With the pumice
rock, I got a void ratio of 62 5%
Just to estimate the internal voids within the pumice, I
performed this same procedure on some standard #57 stone (washed
granite - uncompacted) The voids on the granite came out to be
52% This means that the internal voids within the pumice rock
is just over 10% of the total voids
I am attaching the calculations for your use I would hope that
this would suffice for the review agency to allow 50% voids
(which is actually very conservative for the pumice) If you
think it would help, I will send some pictures of the materials
The supplier does not have a'spec sheet' that would indicated
voids, only specific gravity's, unit weights, and all that good
stuff
VoidRatios.xls Content -Type: application/octet-stream
Content -Encoding: base64
Lecture 6- properties of aquifers.doc� Content -Type: application/msword
Content -Encoding: base64
1 of 1 5/12/2004 10 34 AM

Kchael F Easley, Governor
William G Ross Jr Secretary
North Carolina Department of Environment and Natural Wesources
Alan W K imek P E ,Director
Division of Water Quallty
Coleen H Sullins, Deputy Director
Division of Water Quality
March 22, 2004
CERTIFIED MAIL 7002 1000 0005 2389 8195
fffT-URN RECEIPTREQUESTED
Mr. Bryan English
English Builders
4705 Southport -Supply Hwy Ste 106
Southport, NC 28461
Subject: NOTICE OF RECOMMENDATION FOR ENFORCEMENT
Hampton Inn Outparcel
Stormwater Permit No. SW8 031133
Brunswick County
Dear Mr English
This letter is to notify you that the Wilmington Regional Office of the Division of Water Quality is
considering sending a recommendation for enforcement action to the Director of the Division of
Water Quality The recommendation concerns the violation of North Carolina General Statute
NCGS 143-215 6A(2), failing to apply for or secure a permit required by NCGS 143-2151 You
have failed to obtain a State Stormwater Management Permit for the subject project On March 22,
2004, staff of the Wilmington Regional Office observed the construction of a building at this site.
On November 21, 2003, you submitted a plan revision for the development of an outparcel of a
permitted project, and which indicated that Gordon Lovingood was the owner who had submitted
the plan as a revision to the one we previously approved On February 11, 2004, the Division sent a
request for additional information to Mr Lovingood He recently indicated that he had not authorized
a plan revision, and that you were the owner of the outparcel Since you are not the permittee for
the Hampton Inn, you must submit an offsde permit application for the development of the outparcel
If you have an explanation for this violation that you wish to present, please respond in writing to me
within ten (10) days following receipt of this Notice Your explanation will be reviewed and forwarded
to the Director with the enforcement package for consideration
By copy of this letter to the Building Inspector, this Office is requesting that the Building Inspector
consider withholding building permits and Certificates of Occupancy for this project until this matter
is satisfactonly resolved If you have any questions concerning this matter, please contact Linda
Lewis at [phone]
Sincerely,
Ql"�_ C_V__
Rick Shiver
Water Quality Regional Supervisor
RSSlarl S1WQSISTORMWATIENFLETR1031133.mar04
CC. Town of Southport Building Inspections
Bob Sledge
Linda Lewis
_,VVtl iington Regional Office
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211
Subject: 211
From: "Bonkers" <bonkers@mfire comma
Date: Wed, 12 May 2004 12 47 24 -0400
To: "Laune Munn" <Laune Munn@ncmail nett
Laurie,
Here's the stuff from the "solite" web page Shows porosity to be 69% Page 5 or 6
Good statement, however, its so light, basic compaction, such as with no 57 isnt really
applicable.
C'mon, you know I'm right -)
Steve
Lightweight Concrete.doc Content -Type: app lication/m sword
Content -Encoding: base64
1 of 1 5/12/2004 12 53 PM

211 site
Subject: 211 site
From: "Bonkers" <bonkers@mfire com>
Date: Mon, 10 May 2004 16 32 07 -0400
To: "Laurie Munn" <Laurie Munn@ncmail net>
CC: "Lisa Clark" <lpclark@ncez net>
Laurie,
I have your comments printed out
On no 3, give me as much notice as possible, I need to get my soil guy there to talk to your soil
guy Or maybe we can get Vincent to call Tom Gully, P E , I have his cel number from the site
On no 4, can I stick this on the plans? If not, I'll need to get that application faxed down, please
On no 6, 50% is the number used from when I did a bunch of these in Florida "Solite" is lava
rock, pumice Full of voids in each peace, the 40% is the voids between the peaces Essentially a
rock hard sponge, lol Otherwise I would agree with you totally -)
How soon do we need to return this?
Sincerely
Steve
I of 1 5/11/2004 7 22 AM

Look for RED
Subject. Look for RED
From: "Bonkers" <bonkers@mfire com>
Date: Tue, 11 May 2004 07 54 18 -0400
To: "Laurie Munn" <Laurie Munn@ncmail net>
The deadline for the return is set at May 17, 2004, but you can request an extension if you need one
Vincent is out of the office until May 19th, so you may wish to hold your resubmittal until he can get
out to the site, especially since it sounds like there may be some soil issues It will be best if your
soils scientist can meet him on the site
I agree But that was in Tom's report, and he was Lonservative
Did you make a copy of the application that you submitted? You only need to revise p 2, add the
tributary name, and fax it back over Let me know if you did not make a copy I do not need an
original of this sheet Sorry, I didnt keep a copy, it was pure chaos here, after Lovingood decided
Bryan couldnt connect to the pond I'1 leaving out at 10 30 for meeting all day joy, lol It you can fax
over earlier, call me on the cel line, I'll plug in the fax
It is the department's policy to use a void ratio of 40% We do not have testing done on various types
of materials I will ask the question to Raleigh, but in order to expedite the process, please design the
system using a 40% void ratio
Again, I agree with limestone or granite rock Pumice has ltty-Bitty holes all thru it Reality would be
55% voids, I gave you a break, lol
Let me know if you have anymore questions I usually leave here by 3 30 or 4 Thanks, I didnt realize
you left that early
1 of 1 5/11/2004 7 58 AM

Fw Old'Georgetowne Center Site
Subject: Fw Old Georgetowne Center Site
From: "Bonkers" <bonkers@mfire comma
Date: Tue, 11 May 2004 08 39 19 -0400
To: "Laurie Munn" <Laurie Munn@ncmail nets
From Ken Clark, P E Would you be so nice to look at this -)
Keep in mind, at 2" per hour percolation rate (9 9 hrs) for the first 1" of runoff, in a 24 hour event
that equates to 2 42" of runoff captured and treated
Ken and I came up with the "inspection pipe" simultaneously yesterday evening as a way to
physically see the sediment level
----- Original Message -----
From Kenneth L Clark
To bonkers(c)-mfire corn
Sent Tuesday, May 11, 2004 8 12 AM
Subject Old Georgetowne Center Site
Steve,
If you talk to the review agency today, I have a couple of issues that I would like some clarification on
prior to revising plans
On Comment #5
If this were a situation where we had concentrated flows going into an open storage area, then I would,
fully agree that a bypass is necessary to avoid overloading the storage capability of the basin and/or
producing turbulence that may cause some of the 'first flush' runoff to exit the system prematurely
The way I interpret the proposed design is that the 'first flush' will flow into the trench and be retained
for infiltration through the underlying soil Any runoff in excess of the'first flush' will flow to the
trench, however, it is my thinking that this excess runoff will flow'over top' the first flush runoff
without forcing the 'first flush' runoff up and out of the trench The measures that have been built in
to insure that the trench will work this way include the elevation of the outlet swale being set above
the top elevation of the'design pool' Also, having the inflow evenly distributed (i e , sheet flow)
across the parking lot and over a buffer strip prior to entry into the trench eliminates points of
concentrated flow that may cause turbulence that might stir the 'first flush' water back up to the top of
the trench This stilling effect is further enhanced by the fact that the trench is filled with so-lite and is
set on a flat grade During an extended slow rainfall event, this design will actually allow you to treat
more stormwater than just the first one inch of runoff Given this further explanation, please check
with the review agency to see if the design as proposed is acceptable, as I am confident it will provide
the desired level of treatment
Comment #6
Since we are using a pumice based stone, there are internal voids within the rock that will increase the
overall void ratio Also, because the stone is so light, there is basically no compaction of the stone
within the trench If the review agency is open to reviewing some empertcal data, I will get hold of
some of this material do a void test just to double-check the ratio
Comment #7
I performed the calculations on based on the acreage that will inflow into the infiltration trench for
treatment If you run the calculations based on the total site acreage, then I come up with 1835 cf as
well, however, there is considerable acreage along the tributary that is undisturbed and which will not
I oft 5/11/2004 8 43 AM

Fw Old,Georgetowne Center Site
4
flow into the infiltration trench Please double check with the review agency as to whether calcs
should be run on actual area requiring treatment or based on entire site acreage
Comment #8
Please include a PVC pipe with large performations as an 'observation point' for determining when the
infiltration trench hits the recommended clean -out threshold
I assume that the remaining comments are no big deal to address If you have any questions, give me
a call
Thanks,
Ken Clark
2 of 2 5/1 1/2004 8 43 AM

ATTACHMENT
Old Georgetown Site
Southport, NC
The proposed treatment for achieving 85% TSS removal for this site is the
use of a pumice -filled infiltration trench camouflaged as a landscape bed
Pretreatment of stormwater directed into the trench will be accomplished by
having the stormwater evenly spread across a wide parking area (defacto
level spreader) then allowing the evenly distributed stormwater to flow over
a stone or grass lined surface prior to entering the infiltration trench. The
exception to this will be the stormwater coming from the rear parking area of
the property. This stormwater will be directed into a grass lined swale prior
to emptying into the infiltration trench. Because a lightweight pumice type
stone providing both internal voids and an overall void ratio of at least 50%
is proposed throughout the entire trench, the traditional bottom sand filter
has been eliminated. This type of stone should help filter fine particles from
the stormwater and will provide a good indication of maintenance needs /
replacement by the level of discoloration of the stone Larger particles that
do not attach to the pumice will be captured by a geosynthetic liner along the
base and side of the trench prior to the stormwater entering the native soil
beneath. For storm events producing rainfall in excess of the first 1-inch of
runoff, stormwater will flow overtop the `treatment' stormwater and will be
carried to a nearby channel via a grass lined swale