Effect of environmental conditions on the properties of concretes with different cement types

The paper reports on the changes in properties of concretes with different cement types associated with environmental conditions. Three strength classes with three different cement types (ordinary portland cement PC 42.5 (CEM I 42.5), portland composite cements PKC-A 42.5 (CEM II/A-M 42.5) and PKC-B 32.5R (CEM II/B-M 32.5R)) were used in the study. Also, a mixture was prepared with PC 42.5 and silica fume (SF). The effects of variable ambient conditions on plastic shrinkage of fresh concrete and cement paste, compressive strength, modulus of elasticity, capillary absorption and drying shrinkage of hardened concrete were investigated. In contrast to PC 42.5 cement paste, plastic shrinkage cracks were observed in PKC-B 32.5 and PKC-A 42.5 pastes. Water absorption coefficients of all concretes stored in natural environment were higher at all ages as compared to coefficients of concretes kept in laboratory. Drying shrinkage values of concrete with SF, except the first week, were significantly lower than those of others. Although different behaviors for different cement types were observed, water–cement ratio was one of the dominating factors determining the behavior of concrete. This ratio should be lowered to improve the durability of concrete.