| Sulphate attack in concrete is affected by the (1) permeability and porosity, (2) C3A content, and (3) Ca(OH) 2 content of the mixture. This thesis examines the effects of different quantities and combinations of slag and silica fume and commercially available blends of these SCM's in controlling sulphate attack, and on the three factors above.; When tested by the ASTM C 1012 test for sulphate resistance, the OPC control (C3A = 10.1%) exceeded the 0.10% expansion limit at 200 days. All mixtures containing any quantity of SCM had not exceeded 0.05% expansion at up to 600 days, meaning all blends were very high sulphate resistant by this test.; However, tests of permeability, porosity, pore size distribution and diffusion showed that mixtures containing blends of both silica fume and slag show higher potential sulphate resistance than those containing only one SCM, as may become evident after longer-term sulphate exposure. |
