温度对混凝土强度的影响

Influences of temperature on strength of concrete

基于混凝土材料的宏观和微观结构的组成,研究了混凝土的宏观强度特性,揭示了混凝土的强度主要取决于其孔隙率.水灰比决定了混凝土的孔隙率和强度.环境温度升高加快水泥水化反应速率和水分蒸发速率,对混凝土的早、后期强度产生影响.介绍了温度效应的几种理论:(a)孔隙系统分布理论;(b)SO3最优量理论;(c)内部开裂理论;(d)凝胶体的非均质性理论.研究结果表明,环境温度升高加快了混凝土早期强度的发展,而降低了其后期强度.

Based on the micro- and macro-structure of concrete materials, an analysis was performed of the macro properties of concrete strength. The result shows that the strength of concrete is mainly determined by its porosity, and that the water-cement ratio determines the porosity and strength of concrete under the specified conditions. In consideration of the fact that the rise of environmental temperature accelerates the rates of hydration and water evaporation, retards the formation of the internal structure of concrete, and further results in some influences on the development of the early-stage and later-stage strength of concrete, an analysis was made on the theories about temperature effect on concrete strength, including the distribution theory of the porosity system, the theory of optimal contents of SO_3, the internal cracking theory, the heterogeneity theory of gels, and the expression between temperature and strength of concrete. It is concluded that the rise of temperature accelerates the development of the early-stage strength, but retards the development of the later-stage strength of concrete, and that the influences of temperature on the strength of concrete should be considered by combination with some other factors.