膨胀剂对免振捣自密实混凝土性能的影响

Influences of expansion admixture on performance of self-compacting concrete

研究了膨胀剂掺量对自密实混凝土工作性、力学性能及体积稳定性能的影响;研究了养护制度,不同约束条件对膨胀剂在自密实混凝土中作用效果的影响。研究结果表明,无约束条件下所得到的掺膨胀剂的标养混凝土试块不能正确指导有钢筋约束的实际构件混凝土强度;无论是在干燥环境下,还是在潮湿环境下使用膨胀剂,都应通过试验慎重选择合适掺量。掺量过低,起不到补偿收缩作用,掺量过大,反而会产生负面效应。

The influences of expansion admixture dosage on the workability,the strength performance and the volume stability of selfcompacting concrete were studied. The influences of curing methods, i.e, different moisture and restrained conditions,on the performance of expansion admixture in selfcompacting concrete were investigated. The results showed that the compressive strength of unrestrained cubic specimen under standard curing conditions can not accurately direct the compressive strength of actual reinforcement concrete, the proper dosage of expansion admixtures should be carefully selected through experiments either under the dry or wet conditions. If the dosage is too smaller, the expansion admixture cannot compensate shrinkage,but if too more, it can have illeffect.