膨胀剂对补偿收缩混凝土性能影响的研究进展

Effect of Expansive Agent on the Performance of Shrinkage-Compensated Concrete

通过掺加膨胀剂来补偿收缩变形是解决混凝土收缩开裂的重要途径之一。膨胀剂的掺加往往对补偿收缩混凝土工作性有不利影响,且随掺量增加,不利程度增加。一定掺量范围内,膨胀剂的掺加对补偿收缩混凝土力学性能影响不大,但能改善混凝土耐久性;掺量继续增加则会破坏混凝土微观结构,导致力学性能和耐久性大幅下降。同等掺量下,施加一定外部约束对补偿收缩混凝土密实度和力学性能有改善作用。目前针对低水胶比条件下,膨胀剂对高强高性能混凝土性能的影响研究则相对较少。

Compensating concrete shrinkage by adding expansive agent is one of the most enective approaches to resolve the problem of shrinkage and cracking. Expansive agent has negative effect on the workability of concrete. And with the increasing of the dosage, the degree of adverse effects increases, too. Expansive agent has no effect on the mechanism of shrinkage-compensated concrete within a certain range, but the durability will be improved. However, the further increasing dosage will destruct the microstructure of concrete, resulting in the decrease of mechanism and durability of concrete. When the dosage of expansive agent is constant, the external restraint has a positive effect on the density and mechanism of shrinkage-compensated concrete. NonetheleSs, researching on the properties of shrinkage- compensated concrete which has low ration of water to binder is insufficient.