Long-term drying shrinkage measurements of concretes made with slag-blended cements

This paper an extensive study conducted to distinguish the factors that affect the long-term drying shrinkages of concrete containing blended cements (Type GB). Altogether 28 concrete mixes were tested up to 182 days for drying shrinkage and compressive strengths. The mixes were based on a typical Grade 32 concrete with 80 mm slump. The mixes included two types of cements (Type GP and SL) Type GB ratios of 35/65, 50/50 and 65/35 were tested. In addition to the standard tests, a modified shrinkage test was also carried out to measure the shrinkages between 0, 1, 3 and 7 days. Results show that very large strains occur between 0 and 7 days. No appreciable expansions were observed were observed made with Type GP cement only or with GP/fly ash blends. Based on the results, the paper questions the appropriateness of specifying standard shrinkage tests for concretes containing slag-blended cements