养护条件对混凝土表面层性能的影响  

Effects of Different Curing Conditions on Near-Surface Layer Properties of Concrete

作　　者：李美利[1,2] 钱觉时 徐姗姗[1] 王立霞[1] 

机构地区：[1]重庆大学材料科学与工程学院,重庆400045 [2]河南省建筑科学研究院有限公司,河南郑州450053

出　　处：《建筑材料学报》2009年第6期724-728,共5页Journal of Building Materials

基　　金：国家自然科学基金资助项目(50404005)

摘　　要：研究了自然环境、水中养护、薄膜覆盖3种养护条件对不同粉煤灰掺量混凝土表面吸水率以及表面层（1-5 cm）混凝土的电阻率影响.结果表明,混凝土表面层的吸水率以及电阻率对养护条件特别敏感,掺粉煤灰可降低混凝土的表面吸水率;养护条件主要影响距离表面1-3 cm处混凝土的电阻率,27 d水中养护后,掺粉煤灰试件电阻率与基准试件相差不大,而6 d水中养护和自然养护后,掺粉煤灰试件电阻率明显比基准试件大,且随粉煤灰掺量的增加而增大,从电阻率变化范围来看,27 d水中养护试件的电阻率最小,其次是6 d水中养护的试件,而自然养护的试件最大.混凝土表面电阻率变化能较好反映养护质量的好坏,基于这种变化,对混凝土的养护效果进行定量评价是可行的.Three different curing conditions were applied to the specimens of the concrete with different replacement levels of ordinary Portland cement by fly ash： natural curing, curing in water or curing with plastic sheet. Sorptivity and electrical resistivity tests were performed to investigate the effects of curing on the near-surface layer properties of concrete. The experimental results indicate that the sorptivity coefficient and electrical resistivity of near-surface layer of concrete are very sensitive to the curing conditions. The curing conditions have a significant effect on the sorptivity of concrete, especially in early ages. The sorptivity of concrete with fly ash is lower than that without it. The curing conditions mainly affect the resistivity of the concrete within about 1-3 cm from the surface. The electrical resistivity of concrete with fly ash has a smaller change than the control without fly ash under water curing for 27 d, while the electrical resistivity of concrete containing fly ash is much greater than the control not containing fly ash under natural curing and water curing for 6 d,and the electrical resistivity is significantly enhanced with the increase of fly ash content. As to the change of resistivity of the specimen, that under water curing for 27 d is the smallest, that under water curing for 6 d is smaller,while that under natural curing is the greatest. The curing quality can be known through the change of the resistivity of the near-surface layer concrete.

关 键 词：混凝土表面层 养护条件 吸水率 电阻率 

分 类 号：TU528.01[建筑科学—建筑技术科学]