低温下保温材料对不同龄期混凝土强度的影响

Effect of insulation materials on the strength of concrete at different ages at low temperatures

为防止低温环境下混凝土强度底对工程质量的影响,依托哈尔滨地区冬季施工项目,确定混凝土养护温度分别为-6、-12℃。并以养护温度、养护龄期、混凝土表面有无覆盖保温材料为参数设计10组混凝土试块,通过对混凝土试块进行低温受压试验,开展低温环境下保温材料对不同龄期混凝土强度的研究,结果表明:在低温养护条件下,在混凝土表面覆盖保温材料可有效提高混凝土早期强度,并且随着龄期的增长混凝土早期强度提高幅度逐渐减小;低温养护前期混凝土强度增长迅速,养护龄期7 d后强度增长缓慢,并且温度越低混凝土强度增长越缓慢。在试验数据的基础上,根据混凝土成熟度理论,拟合了3种不同函数模型(对数函数、指数函数、双曲函数)对应混凝土强度-成熟度曲线的参数,对比了不同模型之间拟合的准确性。

In order to prevent the influence of the concrete strength bottom in low temperature environment on the quality of the project,relying on the winter construction project in Harbin area,the concrete curing temperature was determined to be-6℃and-12℃respectively.Ten sets of concrete specimens were designed with the parameters of curing temperature,curing age and concrete surface covered with or without insulation material,and the study of the strength of concrete at different ages under low temperature with insulation material was carried out by conducting low temperature pressure test on concrete specimens.The results show that under the low temperature curing conditions,covering the concrete surface with thermal insulation material can effectively improve the early strength of concrete,and with the growth of the age the early strength of concrete gradually decreases as the age increases.The strength of concrete grows rapidly in the early stage of low temperature curing,and slowly after 7 d of curing age,and the lower the temperature the slower the strength of concrete grows.Based on the experimental data,three different functional models(logarithmic,exponential and hyperbolic functions)were fitted to the concrete strength-maturity curves according to the concrete maturity theory,and the accuracy of the fitting between the different models was compared.