采用膨胀剂抑制混凝土的收缩与开裂

长期以来,混凝土的收缩开裂使建筑结构寿命大大降低,维修费用大大增加。自补偿收缩理论建立以来,采用混凝土膨胀剂抑制混凝土的收缩开裂是行之有效的控制方法。然而现代混凝土的物性因施工技术的要求以及胶凝材料和外加剂种类性能的影响,温度收缩和自收缩日益成为引起混凝土结构开裂的主要表现。同时由于水泥生产中熟料矿物的改变,水泥成品细度的降低,水泥早期强度的提高,致使混凝土早期强度增长加快,弹性模量、徐变松弛等参数随之变化,造成开裂趋势明显加大,因此提高混凝土的抗裂性能,已经十分必要和紧迫。

Restraining Shrinkage and Crack of Concrete by Using of Expansive Agent

For quite a long period, the shrinkage and crack of concrete have greatly shorted the life of structure and increased the cost of maintaining. Restraining the shrinkage and crack of concrete by using of expansive agent has been an effective controlling method since the setting of shrinkage-compensating theory. As the performances of modern concrete being influenced by the construction requests as well as varieties of cementing materials and admixtures, temperature shrinkage and self-shrinkage are main reasons to the cracking of concrete structure. With the changing of clinker minerals, the minishing of fineness of cement products and the increasing of early strength of cement, the early strength of concrete increases faster with relative changes of the parameters such as elastic modulus, creep relaxation etc, as a result, the crack trend boosts. Therefore, it is necessary and urgent to promote anti-crack capability of concrete.