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A23.4-09
©
Canadian Standards Association
November 2009
7.4.5 Structural low-density aggregate
Absorption of structural low-density aggregate, as defined in ASTM C330, shall not exceed 11% when
such aggregate is used in architectural face mixes exposed to the weather.
Note:
Low-density aggregate should not be used in exposed finishes in cold or humid climates unless the performance of
such aggregate has been verified by tests or the aggregate has demonstrated satisfactory performance under similar climatic
conditions.
8 Admixtures
8.1 General
Admixtures for use in precast concrete shall comply with Clause 4.2.4 of CSA A23.1 and
Clause 8.2
of this
Standard.
Note:
Some admixtures can affect the colour tone of concrete; therefore, the same admixture should be used throughout
any part of a project where colour uniformity is required.
8.2 Calcium chloride
Calcium chloride shall not be used in precast concrete.
9 Reinforcement
Reinforcement and prestressing tendons for use in precast concrete shall comply with Clause 6.1 of
CSA A23.1 and, for concrete railroad ties, ASTM A881/A881M and ASTM A911/A911M.
10 Hardware and miscellaneous materials
10.1 General
Hardware and miscellaneous materials for use in precast concrete shall comply with Clause 6.2 of
CSA A23.1 and
Clauses 10.2
and
10.3
of this Standard.
Note:
To prevent rust staining on finished surfaces, all exposed metal inserts, anchorages, and other hardware should be
protected with a rust-preventing material.
10.2 Hardware
10.2.1 Connections
Precast connection hardware shall be identified and located on the shop drawings. The owner shall specify
corrosion protection adequate for the type of exposure and the design service life.
Note:
Types of exposure for which measures such as hot-dip galvanizing or the use of stainless steel should be considered
include the following:
(a) exposure to corrosive environments;
(b) exposure to the weather, condensation, or other sources of moisture; and
(c) exposure within the air or insulation space outside the air barrier of a building.
10.2.2 Tendon deflectors
10.2.2.1
Tendon deflectors shall maintain the tendon location (bundled or spaced) in accordance with the design
criteria and as shown on the shop drawings.
Licensed for/Autorisé à Jed Friesen Sold by/vendu par CSA on/le June/18/2015.
~Single user license only. Storage, distribution or use on network prohibited. Permis d'utilisateur simple seulement.
Le stockage, la distribution ou l'utilisation sur le réseau est interdit.