引入膨胀剂的高强混凝土的收缩补偿研究

Research on compensating shrinkage of high strength concrete incorporated with expansive admixture

将膨胀剂引入高强混凝土 ,意在补偿其自缩、冷缩和干缩 ,使高强混凝土真正成为高性能混凝土。研究了以硅粉、膨胀剂和普通水泥为胶凝材料配制的水泥净浆及其混凝土的收缩补偿过程。得到掺膨胀剂的高强混凝土强度在早期略有降低 ,但在后期有所提高 ;在90～ 1 80d龄期其膨胀率 (水中 )达到 40 0× 1 0 - 6～ 60 0× 1 0 - 6,同时其干缩率没有出现负值 ,仍有 65× 1 0 - 6～ 1 3 5× 1 0 - 6的膨胀。

This paper deals with the shrinkage and compensating shrinkage of hardened cement paste and its high strength concrete incorporated with expansive admixture. Results indicated that the compressive strength of concrete added with expansive admixture was increased about 5% at 28-day and 90-day ages. At 180-day ages its expansion in water reached 400×10\+\{-6\}～600×10\+\{-6\}, and its drying shrinkage did not show negative and its residual expansion was 65×10\+\{-6\}～135×10\+\{-6\} still. The results suggest that the using of expansive admixture in high strength concrete may compensate its autogenous, temperature and drying shrinkage.