Durability performance of a range of marine concretes and the applicability of the South African Service Life Prediction Model

摘要

The paper describes a study that examined and compared the potential durability performance of various geographically distinct South African marine concrete mix types. Mix proportions were designed at two water/binder ratios (0.40 and 0.55) for different material combinations of binder and aggregate types. Sampling was done at 28, 91 and 182 days. Durability performance was inferred from durability index (DI) tests that measure the resistance of concrete to ion, gas and fluid penetration. Comparison was made on the basis of regional concrete type, w/b ratio and mix constituents (binder and aggregate type). All the concrete mixes were further compared to plain CEM I control concrete mixes at each w/b ratio. Results indicate that low w/b ratio and blended binder concrete mixes have low penetrability characteristics. Aggregate type was seen not to have an appreciable influence on the transport properties of concrete. Across the range of geographically different mixes, it was found that with a given concrete grade and binder type, marine concrete mixes are practically comparable. This permits the existing Service Life Prediction Model to be more confidently applied for all marine zones in South Africa with possible application in other geographic regions following further research.