Durability of wheat straw ash concrete exposed to freeze–thaw damage

Abstract

This study investigated the effect of wheat straw ash on the durability of concrete to freeze–thaw deterioration. Three wheat straw ash replacement levels were considered in the study: 5, 10 and 15% by weight of cement. The other experimental parameters investigated in the study included: aggregate type (basalt and pumice), water/binder ratio (0·5 and 0·7) and maximum aggregate size (9·5 and 19 mm). After the initial moist curing, wheat straw ash concrete prisms were subjected to accelerated freeze–thaw cycles following ASTM Procedure B (rapid freezing in air and thawing in water). The freeze–thaw deterioration of wheat straw ash concrete specimens was evaluated using the relative dynamic modulus of elasticity and durability factor. The results showed that the durability of wheat straw ash concrete to freeze–thaw deterioration was greater than that of plain concrete. Furthermore, the durability of wheat straw ash concrete to freeze–thaw deterioration increased with increasing wheat straw ash replacement level. The concrete containing pumice aggregate showed higher durability to freeze–thaw deterioration in comparison with that containing basalt aggregate. The effect of aggregate type was more pronounced for the wheat straw ash concrete than for plain concrete. The concrete at water/binder ratio of 0·5 showed higher durability to freeze–thaw deterioration than that at water/binder ratio of 0·7. The effect of water/binder ratio was more pronounced for the wheat straw ash concrete in comparison with the control concrete. Furthermore, the concrete with maximum aggregate size of 9·5 mm showed higher durability to freeze–thaw deterioration than concrete with maximum aggregate size of 19 mm.