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收缩是水泥基材料的一个非均质特性,它会对混凝土的力学性能、耐久性产生不利影响。设置结构缝,使用预应力钢筋混凝土和特种水泥对预防收缩产生的有害裂缝效果并不明显。目前补偿收缩的方法是使用补偿收缩水泥(SCC)和硫铝酸钙膨胀剂(CSA);然而,混凝土凝结时间加快、坍落度损失、膨胀量和膨胀时间的控制是影响这类材料使用的最大问题。近年来,新型CSA膨胀剂——水化硫铝酸钙膨胀剂在中等强度混凝土(30--35MPa)中补偿收缩效果显著。本文介绍了目前所使用的补偿收缩材料的基本特性,对各种外加剂的成分、反应模式、应用方法和性能做了详细描述。
Shrinkage is a non-homogeneous property of cement-based materials, which can adversely affect the mechanical properties and durability of concrete. Set structural joints, the use of prestressed reinforced concrete and special cement to prevent shrinkage harmful cracking effect is not obvious. The current method of compensating for shrinkage is the use of SCC and CSA; however, the setting of concrete is accelerated, slump loss, control of expansion and expansion time are the factors that influence the use of such materials The biggest problem. In recent years, the new CSA expander - hydrated calcium sulphoaluminate expansion agent in the medium-strength concrete (30 - 35MPa) compensation shrinkage effect significantly. This paper introduces the basic characteristics of the shrinkage-compensating materials currently used, and gives a detailed description of the composition, reaction modes, application methods and properties of various additives.