宁夏盐渍土地区现场暴露混凝土耐久性损伤评价试验

摘要

以掺有不同粉煤灰量的混凝土试件为研究对象，将3种配合比的混凝土试件暴露在具有典型盐渍土特征的宁夏地区，选取相对质量和相对动弹性模量作为评价参数，通过比较分析得出一种更加适合盐渍土地区现场暴露混凝土耐久性损伤的综合评价参数。同时结合现场暴露混凝土微观分析对盐渍土地区混凝土受硫酸盐侵蚀的劣化机理进行了研究，从微观角度分析了盐渍土地区混凝土耐久性能变化的原因。结果表明：混凝土在盐渍土地区受到复杂的化学侵蚀，与土壤中的硫酸盐反应生成了硫铝酸钙晶体填充在孔隙中，综合损伤评价参数能很好地描述盐渍土地区混凝土的耐久性。%The concrete specimens with different amounts of fly ash were taken as research obj ect. The concrete specimens of three kinds of mix ratio were exposed to saline soil with typical characteristics in Ningxia area.The relative mass and relative dynamic elastic modulus were selected as evaluation parameters. Through the comparative analysis, the more suitable comprehensive damage assessment parameters of durability evaluation of the concrete field exposed in the saline area were obtained.At the same time,the degradation mechanism of concrete under sulfate erosion in saline soil was studied combining with microcosmic analysis of field exposed concrete.The reasons for the durability change of concrete in saline soil area were analyzed from micro perspective.The results show that the concrete is subj ected to complex chemical erosion in the saline soil area, and react with sulfate in soil to form calcium sulphoaluminate crystals which is filled in the pore.The durability of concrete in saline soil area can be well described by the comprehensive damage assessment parameters.