ASTM C1504M-15
(Specification)Standard Specification for Manufacture of Precast Reinforced Concrete Three-Sided Structures for Culverts and Storm Drains (Metric)
Standard Specification for Manufacture of Precast Reinforced Concrete Three-Sided Structures for Culverts and Storm Drains (Metric)
ABSTRACT
This specification covers single-cell precast conventionally reinforced concrete three-sided structures intended to be used for the construction of culverts and for the conveyance of storm water. Precast reinforced concrete three-sided structures manufactured in accordance with this specification shall be designated by span, rise, and design earth cover. The reinforced concrete shall consist of cementitious materials, mineral aggregates and water, in which steel has been embedded in such a manner that the steel and concrete act together. The three-sided section's dimensions and reinforcement details shall be as required by design. Splices in the circumferential reinforcement shall be made by lapping. The precast reinforced concrete three-sided structures shall be produced with tongue and groove ends, flat butt ends or key-way ends. The aggregates shall be sized, graded, proportioned, and mixed with such proportions of cementitious materials and water as will produce a homogeneous concrete mixture of such quality that each section will conform to the test and design requirements. The three-sided sections shall be cured for a sufficient length of time so that the concrete will develop the required compressive strength. The forms used in manufacture shall be sufficiently rigid and accurate to maintain the three-sided section dimensions within the permissible variations. Handling devices or holes shall be permitted in each three-sided section for the purpose of handling and laying. Cylinders and cores shall be obtained and tested for compressive strength to meet the requirements prescribed.
SCOPE
1.1 This specification covers single-cell precast conventionally reinforced concrete three-sided structures intended to be used for the construction of culverts and for the conveyance of storm water.
1.2 This specification is the metric counterpart of Specification C1504; therefore, no imperial (metric) equivalents are presented in this specification.
Note 1: This specification is primarily a manufacturing and purchasing specification. The successful performance of this product depends upon the proper selection of the geometric section, bedding, backfill, and care that the installation conforms to the construction specifications. The purchaser of the precast reinforced concrete three-sided structure specified herein is cautioned that proper correlation of the loading conditions and the field requirements with the geometric section specified and provisions for inspection at the construction site are required.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
General Information
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Designation: C1504M −15
StandardSpecification for
Manufacture of Precast Reinforced Concrete Three-Sided
Structures for Culverts and Storm Drains (Metric)
This standard is issued under the fixed designation C1504M; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope C31/C31M Practice for Making and Curing Concrete Test
Specimens in the Field
1.1 This specification covers single-cell precast convention-
C33 Specification for Concrete Aggregates
ally reinforced concrete three-sided structures intended to be
C39/C39M Test Method for Compressive Strength of Cylin-
used for the construction of culverts and for the conveyance of
drical Concrete Specimens
storm water.
C150 Specification for Portland Cement
1.2 This specification is the metric counterpart of Specifi-
C260/C260M Specification for Air-Entraining Admixtures
cation C1504; therefore, no imperial (metric) equivalents are
for Concrete
presented in this specification.
C309 Specification for Liquid Membrane-Forming Com-
NOTE 1—This specification is primarily a manufacturing and purchas-
pounds for Curing Concrete
ing specification. The successful performance of this product depends
C494/C494M Specification for Chemical Admixtures for
upon the proper selection of the geometric section, bedding, backfill, and
Concrete
care that the installation conforms to the construction specifications. The
purchaseroftheprecastreinforcedconcretethree-sidedstructurespecified C497M Test Methods for Concrete Pipe, Manhole Sections,
herein is cautioned that proper correlation of the loading conditions and
or Tile (Metric)
the field requirements with the geometric section specified and provisions
C595 Specification for Blended Hydraulic Cements
for inspection at the construction site are required.
C618 Specification for Coal Fly Ash and Raw or Calcined
1.3 The values stated in either SI units or inch-pound units
Natural Pozzolan for Use in Concrete
are to be regarded separately as standard. The values stated in
C822 Terminology Relating to Concrete Pipe and Related
each system may not be exact equivalents; therefore, each
Products
system shall be used independently of the other. Combining
C989 Specification for Slag Cement for Use in Concrete and
values from the two systems may result in non-conformance
Mortars
with the standard.
C1116 Specification for Fiber-Reinforced Concrete and
Shotcrete
2. Referenced Documents
C1602/C1602M Specification for Mixing Water Used in the
2.1 ASTM Standards:
Production of Hydraulic Cement Concrete
A1064/A1064M Specification for Carbon-Steel Wire and
2.2 AASHTO Standard:
Welded Wire Reinforcement, Plain and Deformed, for
AASHTO LRFD Bridge Design Specifications
Concrete
A615/A615M SpecificationforDeformedandPlainCarbon-
2.3 ACI Standard:
Steel Bars for Concrete Reinforcement
ACI 318 Building Code Requirements for Structural Con-
A706/A706M Specification for Deformed and Plain Low-
crete and Commentary
Alloy Steel Bars for Concrete Reinforcement
3. Terminology
3.1 Definitions—For definitions of terms, see Terminology
This specification is under the jurisdiction of ASTM Committee C13 on
C822.
Concrete Pipe and is the direct responsibility of Subcommittee C13.07 on
Acceptance Specifications and Precast Concrete Box Sections.
Current edition approved Jan. 15, 2015. Published January 2015. Originally
approved in 2001. Last previous edition approved in 2014 as C1504M – 14. DOI:
10.1520/C1504M-15. Available from American Association of State Highway and Transportation
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM http://www.transportation.org.
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican Concrete Institute (ACI), P.O. Box 9094, Farmington
the ASTM website. Hills, MI 48333-9094, http://www.concrete.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1504M − 15
4. Types reinforcement, deformed and plain steel bars for reinforced
concrete are permitted conforming to Specification A706/
4.1 Precast reinforced concrete three-sided structures manu-
A706M or A615/A615M, Grade 420, and longitudinal distri-
factured in accordance with this specification shall be desig-
bution reinforcement shall consist of welded wire reinforce-
nated by span, rise, and design earth cover.
ment or deformed billet-steel bars conforming to Specification
A706/A706M or A615/A615M, Grade 420.
5. Basis of Acceptance
NOTE 2—This specification does not address reinforcement with pre-
5.1 Acceptability of the three-sided sections produced in
stressing strand or any other form of pre-tensioning or post-tensioning.
accordance with Section 7 shall be determined by the results of
6.6 Synthetic Fibers—Collated fibrillated virgin polypropyl-
the concrete compressive strength tests described in Section
ene fibers may be used, at the manufacturer’s option, in
10, by the material requirements described in Section 6, and by
three-sided structures as a nonstructural manufacturing mate-
inspection of the finished three-sided sections.
rial. Only type III synthetic fibers designed and manufactured
5.2 Three-sided sections shall be considered ready for
specifically for use in concrete and conforming to the require-
acceptance when they conform to the requirements of this
ments of Specification C1116 shall be accepted.
specification.
6.7 Water—Water used in the production of concrete shall
be potable or non-potable water that meets the requirements of
6. Materials
Specification C1602/C1602M.
6.1 Reinforced Concrete—The reinforced concrete shall
consist of cementitious materials, mineral aggregates and
7. Design
water, in which steel has been embedded in such a manner that
7.1 Design Criteria—The three-sided section’s dimensions
the steel and concrete act together.
and reinforcement details shall be as required by design, in
6.2 Cementitious Materials:
accordance with Section 3, 5, and 12.14 of the American
6.2.1 Cement—Cement shall conform to the requirements
Association of State Highways and Transportation Officials
for portland cement of Specification C150 or shall be portland
(AASHTO) LRFD Bridge Design Specifications. The mini-
blast-furnace slag cement or portland-pozzolan cement con-
mum concrete compressive strength shall be 35 MPa, and the
forming to the requirements of Specification C595, except that
minimum steel yield strength shall be 450 MPa for welded-
the pozzolan constituent in the Type IP portland pozzolan
wirereinforcementand420MPafordeformedbillet-steelbars.
cement shall be fly ash.
7.2 Placement of Reinforcement—The minimum cover of
6.2.2 Fly Ash—Fly ash shall conform to the requirements of
concrete over the circumferential reinforcing diameter shall be
Specification C618, Class F or Class C.
25 mm for bar reinforcement and welded wire reinforcement
6.2.3 Ground Granulated Blast-Furnace Slag (GGBFS)—
for all structures up to 3.6 m in span and 38 mm for longer
GGBFS shall conform to the requirements of Grade 100 or 120
spans subject to provisions of Section 11 for both bar rein-
of Specification C989.
forcement and welded wire reinforcement. The clear distance
6.2.4 Allowable Combinations of Cementitious Materials—
of the end circumferential wires shall be not less than 13 mm
The combination of cementitious materials used in concrete
nor more than 50 mm from the ends of each section. For
shall be one of the following:
three-sided sections covered by less than 0.6 m of fill,
(1) Portland cement only,
minimum cover for the reinforcement in the top of the top slab
(2) Portland blast-furnace slag cement only,
shall be 50 mm, subject to the provisions of Section 11.
(3) Portland pozzolan cement only,
Reinforcementshallbeassembledutilizinganycombinationof
(4) A combination of portland cement and fly ash,
single or multiple layers of welded-wire reinforcement, not to
(5) A combination of portland cement and ground granu-
exceed three layers or utilizing single or multiple layers of
lated blast-furnace slag,
deformed billet steel bars, not to exceed two layers. The
(6) A combination of portland cement, ground granulated
welded-wire reinforcement on 7.3 shall be composed of
blast furnace slag, and fly ash.
circumferential and longitudinal wires meeting the spacing
(7) Acombinationofportlandpozzolancementandflyash.
requirements of 7.3 and shall contain sufficient longitudinal
6.3 Aggregates—Aggregates shall conform to Specification
wires extending through the three-sided section to maintain the
C33, except that the requirements for gradation shall not apply.
shape and position of reinforcement. Longitudinal distribution
6.4 Admixtures and Blends—Admixtures and blends shall reinforcement may be welded-wire reinforcement or deformed
conform to Specification C494/C494M. billet-steel bars and shall meet the spacing requirements of 7.3.
6.4.1 Air Entraining Admixtures—Air entraining will be The ends of the longitudinal distribution reinforcement shall
required on all products produced with positive slump, wet- not be more than 50 mm from the ends of a three-sided section.
cast concrete, and shall conform to the requirements of The exposure of the ends of longitudinals, stirrups, and spacers
Specification C260/C260M. used to position the reinforcement shall not be a cause for
rejection.
6.5 Steel Reinforcement—Reinforcement shall consist of
welded wire reinforcement conforming to Specification 7.3 Laps, Welds, and Spacing—Splices in the circumferen-
A1064/A1064M for steel wire and welded wire reinforcement, tial reinforcement shall be made by lapping. For welded wire
plain and deformed, for concrete. For circumferential reinforcement, the overlap measured between the outermost
C1504M − 15
longitudinalwiresofeachreinforcementsheetortheoutermost required compressive strength by the time of delivery.Any one
bars shall not be less than the spacing of the longitudinal wires of the following methods of curing or combinations thereof
plus 50 mm but not less than 250 mm. For splices of deformed may be used:
billet steel bars, the overlap shall meet the requirements of
9.2.1 Steam Curing—The three-sided section may be low
AASHTO. The outside circumferential reinforcement in the
pressure, steam-cured by a system that will maintain a moist
top slab shall be continuous with or be lapped with the outside
atmosphere.
circumferentialreinforcementinthesides.Ifweldsaremadeto
9.2.2 Water Curing—The three-sided section may be water-
welded wire reinforcement circumferential reinforcement, they
cured by any method that will keep the sections moist.
shall be made only to selected circumferential wires that are
9.2.3 Membrane Curing—A sealing membrane conforming
not less than 450 mm apart along the longitudinal axis of the
to the requirements of Specification C309 may be applied and
three-sided section. When spacers are welded to circumferen-
shall be left intact until the required concrete compressive
tial wires, they shall be welded only to these selected circum-
strength is attained. The concrete temperature at the time of
ferential wires. There shall be no welding to other circumfer-
applicationshallbewithin6°Coftheatmospherictemperature.
ential wires. No welds shall be made to the inside
All surfaces shall be kept moist prior to the application of the
circumferential wires in the middle third of the top span. No
compounds and shall be damp when the compound is applied.
welds shall be made to the outside circumferential wires in the
9.3 Forms—The forms used in manufacture shall be suffi-
top span within one fourth of the span from the corners or in
ciently rigid and accurate to maintain the three-sided section
any location in either leg. Welding of deformed billet steel bar
dimensions within the permissible variations given in Section
circumferential reinforcement is prohibited in all cases. When
11. All casting surfaces shall be smooth nonporous material.
distribution reinforcement is to be fastened to a cage by
welding, it shall be welded only to longitudinal wires or bars
9.4 Handling—Handling devices or holes shall be permitted
and only near the ends of the three-sided section. The spacing
in each three-sided section for the purpose of handling and
center to center of the circumferential (wires) reinforcement
laying.
shall not be less than 50 mm nor more than 100 mm for welded
wire reinforcement or less than 50 mm nor more than 200 mm
10. Physical Requirements
for deformed billet steel bars. The spacing center to center of
10.1 Type of Test Specimen—Compression tests for deter-
the longitudinal reinforcement shall not be more than 200 mm
mining concrete compressive strength shall be made on either
for welded wire reinforcement or more than 300 mm for
standard rodded concrete cylinders or concrete cylinders com-
deformed billet steel bars. If welds are made to Grade 420
pacted and cured in like manner as the three-sided section, or
reinforcing bars, weldable bars conforming to Specification
on cores drilled from the three-sided section.
A706/A706M shall be used.
10.2 Compression Testing of Cylinders:
8. Joints
10.2.1 Cylinders shall be obtained and tested for compres-
8.1 The precast reinforced concrete three-sided structures
sive strength in accordance with the provisions of Practice
shall be produced with tongue and groove ends, flat butt ends
C31/C31M and Test Method C39/C39M, except that the
or key-way ends.The ends shall be of such design and the ends
cylinders may be prepared by methods comparable to those
of the three-sided sections so formed that each section can be
used to consolidate and cure the concrete in the actual
laid together to make a continuous line of sections compatible
three-sided section manufactured. Cylindrical specimens of
with the permissible variations given in Section 11.
sizesotherthan150by300mmmaybeusedprovidedallother
9. Manufacture
requirements of Practice C31/C31M are met. If the concrete is
of a consistency too stiff for compaction by rodding or internal
9.1 Mixture—The aggregates shall be sized, graded,
vibration, the alternate method described in Section II of Test
proportioned,andmixedwithcementitiousmaterialsandwater
Methods C497M may be used. Cylinders shall be exposed to
and admixture, if any, to produce a thoroughly mixed concrete
similar curing time and temperature conditions as the manu
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C1504M − 14 C1504M − 15
Standard Specification for
Manufacture of Precast Reinforced Concrete Three-Sided
Structures for Culverts and Storm Drains (Metric)
This standard is issued under the fixed designation C1504M; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This specification covers single-cell precast conventionally reinforced concrete three-sided structures intended to be used
for the construction of culverts and for the conveyance of storm water.
1.2 This specification is the metric counterpart of Specification C1504; therefore, no imperial (metric) equivalents are presented
in this specification.
NOTE 1—This specification is primarily a manufacturing and purchasing specification. The successful performance of this product depends upon the
proper selection of the geometric section, bedding, backfill, and care that the installation conforms to the construction specifications. The purchaser of
the precast reinforced concrete three-sided structure specified herein is cautioned that proper correlation of the loading conditions and the field
requirements with the geometric section specified and provisions for inspection at the construction site are required.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the standard.
2. Referenced Documents
2.1 ASTM Standards:
A1064/A1064M Specification for Carbon-Steel Wire and Welded Wire Reinforcement, Plain and Deformed, for Concrete
A615/A615M Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement
A706/A706M Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete Reinforcement
C31/C31M Practice for Making and Curing Concrete Test Specimens in the Field
C33 Specification for Concrete Aggregates
C39/C39M Test Method for Compressive Strength of Cylindrical Concrete Specimens
C150 Specification for Portland Cement
C260/C260M Specification for Air-Entraining Admixtures for Concrete
C309 Specification for Liquid Membrane-Forming Compounds for Curing Concrete
C494/C494M Specification for Chemical Admixtures for Concrete
C497M Test Methods for Concrete Pipe, Manhole Sections, or Tile (Metric)
C595 Specification for Blended Hydraulic Cements
C618 Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete
C822 Terminology Relating to Concrete Pipe and Related Products
C989 Specification for Slag Cement for Use in Concrete and Mortars
C1116 Specification for Fiber-Reinforced Concrete and Shotcrete
C1602/C1602M Specification for Mixing Water Used in the Production of Hydraulic Cement Concrete
2.2 AASHTO Standard:
AASHTO LRFD Bridge Design Specifications
This specification is under the jurisdiction of ASTM Committee C13 on Concrete Pipe and is the direct responsibility of Subcommittee C13.07 on Acceptance
Specifications and Precast Concrete Box Sections.
Current edition approved Feb. 1, 2014Jan. 15, 2015. Published March 2014January 2015. Originally approved in 2001. Last previous edition approved in 20132014 as
C1504M – 13a.C1504M – 14. DOI: 10.1520/C1504M-14.10.1520/C1504M-15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American Association of State Highway and Transportation Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,
http://www.transportation.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1504M − 15
2.3 ACI Standard:
ACI 318 Building Code Requirements for Structural Concrete and Commentary
3. Terminology
3.1 Definitions—For definitions of terms, see Terminology C822.
4. Types
4.1 Precast reinforced concrete three-sided structures manufactured in accordance with this specification shall be designated by
span, rise, and design earth cover.
5. Basis of Acceptance
5.1 Acceptability of the three-sided sections produced in accordance with Section 7 shall be determined by the results of the
concrete compressive strength tests described in Section 10, by the material requirements described in Section 6, and by inspection
of the finished three-sided sections.
5.2 Three-sided sections shall be considered ready for acceptance when they conform to the requirements of this specification.
6. Materials
6.1 Reinforced Concrete—The reinforced concrete shall consist of cementitious materials, mineral aggregates and water, in
which steel has been embedded in such a manner that the steel and concrete act together.
6.2 Cementitious Materials:
6.2.1 Cement—Cement shall conform to the requirements for portland cement of Specification C150 or shall be portland
blast-furnace slag cement or portland-pozzolan cement conforming to the requirements of Specification C595, except that the
pozzolan constituent in the Type IP portland pozzolan cement shall be fly ash.
6.2.2 Fly Ash—Fly ash shall conform to the requirements of Specification C618, Class F or Class C.
6.2.3 Ground Granulated Blast-Furnace Slag (GGBFS)—GGBFS shall conform to the requirements of Grade 100 or 120 of
Specification C989.
6.2.4 Allowable Combinations of Cementitious Materials—The combination of cementitious materials used in concrete shall be
one of the following:
(1) Portland cement only,
(2) Portland blast-furnace slag cement only,
(3) Portland pozzolan cement only,
(4) A combination of portland cement and fly ash,
(5) A combination of portland cement and ground granulated blast-furnace slag,
(6) A combination of portland cement, ground granulated blast furnace slag, and fly ash.
(7) A combination of portland pozzolan cement and fly ash.
6.3 Aggregates—Aggregates shall conform to Specification C33, except that the requirements for gradation shall not apply.
6.4 Admixtures and Blends—Admixtures and blends shall conform to Specification C494/C494M.
6.4.1 Air Entraining Admixtures—Air entraining will be required on all products produced with positive slump, wet-cast
concrete, and shall conform to the requirements of Specification C260/C260M.
6.5 Steel Reinforcement—Reinforcement shall consist of welded wire reinforcement conforming to Specification A1064/
A1064M for steel wire and welded wire reinforcement, plain and deformed, for concrete. For circumferential reinforcement,
deformed and plain steel bars for reinforced concrete are permitted conforming to Specification A706/A706M or A615/A615M,
Grade 420, and longitudinal distribution reinforcement shall consist of welded wire reinforcement or deformed billet-steel bars
conforming to Specification A706/A706M or A615/A615M, Grade 420.
NOTE 2—This specification does not address reinforcement with prestressing strand or any other form of pre-tensioning or post-tensioning.
6.6 Synthetic Fibers—Collated fibrillated virgin polypropylene fibers may be used, at the manufacturer’s option, in three-sided
structures as a nonstructural manufacturing material. Only type III synthetic fibers designed and manufactured specifically for use
in concrete and conforming to the requirements of Specification C1116 shall be accepted.
6.7 Water—Water used in the production of concrete shall be potable or non-potable water that meets the requirements of
Specification C1602/C1602M.
7. Design
7.1 Design Criteria—The three-sided section’s dimensions and reinforcement details shall be as required by design, in
accordance with Section 3, 5, and 12.14 of the American Association of State Highways and Transportation Officials (AASHTO)
Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington Hills, MI 48333-9094, http://www.concrete.org.
C1504M − 15
LRFD Bridge Design Specifications. The minimum concrete compressive strength shall be 35 MPa, and the minimum steel yield
strength shall be 450 MPa for welded-wire reinforcement and 420 MPa for deformed billet-steel bars.
7.2 Placement of Reinforcement—The minimum cover of concrete over the circumferential reinforcing diameter shall be 25 mm
for bar reinforcement and welded wire reinforcement for all structures up to 3.6 m in span and 38 mm for longer spans subject
to provisions of Section 11 for both bar reinforcement and welded wire reinforcement. The clear distance of the end circumferential
wires shall be not less than 13 mm nor more than 50 mm from the ends of each section. For three-sided sections covered by less
than 0.6 m of fill, minimum cover for the reinforcement in the top of the top slab shall be 50 mm, subject to the provisions of
Section 11. Reinforcement shall be assembled utilizing any combination of single or multiple layers of welded-wire reinforcement,
not to exceed three layers or utilizing single or multiple layers of deformed billet steel bars, not to exceed two layers. The
welded-wire reinforcement on 7.3 shall be composed of circumferential and longitudinal wires meeting the spacing requirements
of 7.3 and shall contain sufficient longitudinal wires extending through the three-sided section to maintain the shape and position
of reinforcement. Longitudinal distribution reinforcement may be welded-wire reinforcement or deformed billet-steel bars and
shall meet the spacing requirements of 7.3. The ends of the longitudinal distribution reinforcement shall not be more than 50 mm
from the ends of a three-sided section. The exposure of the ends of longitudinals, stirrups, and spacers used to position the
reinforcement shall not be a cause for rejection.
7.3 Laps, Welds, and Spacing—Splices in the circumferential reinforcement shall be made by lapping. For welded wire
reinforcement, the overlap measured between the outermost longitudinal wires of each reinforcement sheet or the outermost bars
shall not be less than the spacing of the longitudinal wires plus 50 mm but not less than 250 mm. For splices of deformed billet
steel bars, the overlap shall meet the requirements of AASHTO. The outside circumferential reinforcement in the top slab shall
be continuous with or be lapped with the outside circumferential reinforcement in the sides. If welds are made to welded wire
reinforcement circumferential reinforcement, they shall be made only to selected circumferential wires that are not less than 450
mm apart along the longitudinal axis of the three-sided section. When spacers are welded to circumferential wires, they shall be
welded only to these selected circumferential wires. There shall be no welding to other circumferential wires. No welds shall be
made to the inside circumferential wires in the middle third of the top span. No welds shall be made to the outside circumferential
wires in the top span within one fourth of the span from the corners or in any location in either leg. Welding of deformed billet
steel bar circumferential reinforcement is prohibited in all cases. When distribution reinforcement is to be fastened to a cage by
welding, it shall be welded only to longitudinal wires or bars and only near the ends of the three-sided section. The spacing center
to center of the circumferential (wires) reinforcement shall not be less than 50 mm nor more than 100 mm for welded wire
reinforcement or less than 50 mm nor more than 200 mm for deformed billet steel bars. The spacing center to center of the
longitudinal reinforcement shall not be more than 200 mm for welded wire reinforcement or more than 300 mm for deformed billet
steel bars. If welds are made to Grade 420 reinforcing bars, weldable bars conforming to Specification A706/A706M shall be used.
8. Joints
8.1 The precast reinforced concrete three-sided structures shall be produced with tongue and groove ends, flat butt ends or
key-way ends. The ends shall be of such design and the ends of the three-sided sections so formed that each section can be laid
together to make a continuous line of sections compatible with the permissible variations given in Section 11.
9. Manufacture
9.1 Mixture—The aggregates shall be sized, graded, proportioned, and mixed with cementitious materials and water and
admixture, if any, to produce a thoroughly mixed concrete of such quality that the structures will conform to the design
requirements of this specification. All concrete shall have a water-cementitious materials ratio not exceeding 0.53 by weights
except that for concrete exposed to cyclic freeze/thaw the water-cementitious materials ratio shall not exceed 0.45. Cementitious
materials shall be as specified in 6.2 and shall be added to the mix in a proportion not less than 280 kg/m unless mix designs with
a lower cementitious materials content demonstrate that the quality and performance of the three-sided sections meet the
requirements of this specification. Wet cast concrete subject to freeze/thaw cycle shall be air-entrained. Air entrainment amounts
shall be in accordance with ACI 318-11, Chapter 4, for the appropriate Exposure Class.
9.2 Curing—The three-sided sections shall be cured for a sufficient length of time so that the concrete will develop the required
compressive strength by the time of delivery. Any one of the following methods of curing or combinations thereof may be used:
9.2.1 Steam Curing—The three-sided section may be low pressure, steam-cured by a system that will maintain a moist
atmosphere.
9.2.2 Water Curing—The three-sided section may be water-cured by any method that will keep the sections moist.
9.2.3 Membrane Curing—A sealing membrane conforming to the requirements of Specification C309 may be applied and shall
be left intact until the required concrete compressive strength is attained. The concrete temperature at the time of application shall
be within 6°C of the atmospheric temperature. All surfaces shall be kept moist prior to the application of the compounds and shall
be damp when the compound is applied.
9.3 Forms—The forms used in manufacture shall be sufficiently rigid and accurate to maintain the three-sided section
dimensions within the
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Questions, Comments and Discussion
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