Section 4 Cover for Durability

In AS3600, durability of the structure is very much related to individual surfaces of a member and to the compressive strength of the concrete.

For one member to have the same durability resistance as another member, AS3600 requires the same cover to the nearest reinforcement or tendon, but the method of selecting the exposure classification and the appropriate concrete strength requires a number of factors to be considered.

The following information must be obtained before cover for corrosion protection is determined:

(a) the most severe Exposure Classification for durability (A1 to U);

(b) the characteristic compressive strength of the concrete ƒ’c for the most severe situation for use in strength, serviceability and durability design, allowing for abrasion and freeze/thaw conditions;

(c) the degree of compaction; and

(d) the type of formwork.

Cover for Concrete Placement

Clause 4.10.2 limits the minimum cover, in the absence of a detailed analysis, to either the reinforcement bar diameter or the maximum nominal aggregate size, whichever is the larger.

Cover for corrosion resistance table

The downloadable table (above) is a combination of tables from AS3600-2009 clauses 4.3, 4.4, 4.5, 4.10.3.2 and 4.10.3.5 for the selection of minimum cover for corrosion resistance of reinforcing and prestressing steel.