碳化对碱矿渣水泥石干燥收缩的影响

Influence of Carbonation on Drying Shrinkage of Alkali-Activated Slag Cement Stone

为研究碳化行为对碱性胶凝材料干燥收缩的影响,以水玻璃或NaOH为碱组分,制备φ27.5×50 mm碱矿渣水泥石试件,并测量φ27.5×1 mm水泥石薄片在干缩条件与碳化条件下的直径变化率,以表征碱矿渣水泥石的干燥收缩与碳化收缩.结果表明：在（20±1）℃,相对湿度（70±5）％的条件下,以NaOH为碱组分的碱矿渣水泥石干燥收缩大于以水玻璃为碱组分的碱矿渣水泥石干燥收缩;碳化使硅酸盐水泥石的收缩增加,但未增加碱矿渣水泥石的收缩;碱当量适当提高有利于减小碱矿渣水泥石的干燥收缩与碳化收缩;以模数为1.2～1.5的水玻璃配制的碱矿渣水泥石干燥收缩与碳化收缩较小.

In order to study the effects of carbonation behavior of alkali-activated cementitious material on drying shrinkage, alkali-activated slag cement stone （AASS） specimen of 427. 5 × 50 mm was prepared by using water glass （WG） and sodium hydroxide （NH） as the alkali activator, and diameter change rate of φ27. 5× 1 mm cement sheets under drying and carbonation condition was measured to characterize the dr- ying shrinkage and carbonation shrinkage of cement stone. The results show that in the temperature of （20±1） ℃ and relative humidity of （70± 5）%, drying shrinkage of AASS activated with NH is greater than that of AASS activated with WG. Carbonation increases the shrinkage of Portland cement stone, but does not increase the shrinkage of AASS. The appropriate raise of Na_2O is helpful to reduce drying shrink- age and carbonization shrinkage of AASS. When water glass with the modulus of 1.2 - 1.5 is used as the activator, drying shrinkage and carbonation shrinkage is relatively small.