干寒大温差环境下混凝土的抗裂性能、力学性能及气孔结构分析

Analysis of Crack Resistance,Mechanical Properties and Pore Size Distribution of Concrete in a Certain Environment of Dryness-Coldness and Large Range of Temperature

试验研究了干寒大温差环境养护下的混凝土开裂过程、抗压强度及28 d龄期的孔径分布情况,分析了混凝土的初始开裂面积、气孔结构与抗压强度之间的关系,并与标准养护下的试验结果进行了对比分析。结果表明:在干寒大温差的养护条件下,混凝土的抗裂性能和力学性能更差,具体表现为初裂时间更短、初裂长度、初裂宽度更大、裂缝总条数更多;混凝土同龄期的抗压强度也较标准养护下要小,并与混凝土的初始开裂面积存在一定的相关性;孔径分布较标准养护下有一定的差异,主要表现为小孔径的孔更少,大孔径的孔更多,孔径分布朝着大孔径的方向移动;除此之外,水胶比也对混凝土的抗裂性、抗压强度和孔径分布有影响。

Cracking process,compressive strength and 28 d pore size distribution of concrete were studied in a certain environment of dryness-coldness and large range of temperature,and the relationship between initial cracking area,pore structure and compressive strength of concrete was analyzed,and compared with the results of standard curing. The results show that in a certain environment of dryness-coldness and large range of temperature,the crack resistance and mechanical properties of concrete are worse than it is in standard curing,more concretely,the initial cracking time is shorter,the initial crack length and the crack width are larger and the total number of cracks is more. In the same curing duration,the compressive strength of concrete is smaller than that which is in a standard curing,and there is a certain correlation between compressive strength and initial cracking area of concrete. Morever,there are some differences in the pore size distribution. The main performance is that the small holes is fewer,the largeholes is more and the pore size distribution moves towards the large aperture. In addition,the water to binder ratio also has an effect on the crack resistance,compressive strength and pore size distribution of concrete.