Exposure Classifications for the Tweed Heads Coastal Environment
Concrete placed in or near coastal environments is subject to Australian Standard AS 1379 exposure classifications — a rating system that determines the minimum cement content, water-cement ratio, and strength grade required based on how aggressive the surrounding environment is.
Exposure Class
Environment
Minimum Strength Grade
A1
Interior / above ground, non-aggressive
20 MPa
A2
Interior / above ground, moderate
25 MPa
B1
Near-coastal, some salt air exposure
32 MPa
B2
Coastal, direct salt air or spray
40 MPa
