Civil Engineering Reference
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5.8 Concrete Cover
The vertical or prestressing steel shall have a cover of concrete to the
outside face or to the inside void not smaller than 1 in. The minimum
concrete cover on spirals shall be at least than 3/4 in.
6. MATERIALS
6.1 Concrete
6.1.1
Mix
: The wet concrete mix used shall contain no more than 0.40
pounds per cubic yard (lbs/cy) of total chloride ions and shall have
a maximum water-cement ratio of 0.40 by weight.
6.1.2
Concrete cylinder strength
: Concrete used shall have a static cylin-
der compressive strength (known as
f
c
) at 28 days not less than
10,000 psi. The cement, water, aggregates, and admixtures used shall
conform to the applicable ASTM standards for those materials and
be of such quality as to prevent pyrite staining or damage due to
sulfates or adverse aggregate alkali reaction.
6.1.3
Materials
: All concrete material shall conform to the latest revision
of ACI 318. The chemical properties of all concrete materials shall
be such that neither pyrite staining nor effl orescence due to sulfates
and/or chlorides will occur.
Portland cement shall conform to the latest revision of ASTM
C150.
Ready-mix concrete shall conform to the latest revision of ASTM
C94.
Aggregates shall conform to the latest revision of ASTM C33 or
C330. Course aggregate shall be crushed stone that is clean, tough,
and well graded. The maximum size shall be 3/4 in. or three-
fourths of the clear spacing between the reinforcing steel or of the
clear spacing between the reinforcing steel and the surface of the
pole. The resistance to abrasion shall not exceed a percentage of
wear of 40% per the latest revision of ASTM C131. Fine aggregate
shall be natural sand consisting of clean, strong, hard, durable,
uncoated, and well-graded particles.
Water used in mixing concrete shall be free of oils, acids, alkalis,
salts, organic matter, or other substances in amounts that may be
harmful to concrete or steel.
Chemical admixtures shall conform to the latest revision of ASTM
C494. Air entraining agents, if any, shall conform to the latest
revision of ASTM C260; the fl y ash or other pozzolanic admix-
tures shall conform to the latest revision of ASTM C618.
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