辅助胶凝材料对再生混凝土性能影响的研究  

Study on the influence of supplementary cementitious materials on the performance of recycled concrete

作　　者：徐美贞 张道明 XU Mei-zhen;ZHANG Dao-ming(Chengbang Ecological Environment Co.,Ltd.,Hangzhou 310008,China;College of Architecture and Civil Engineering,Qiqihar University,Heilongjing Qiqihar 161006,China)

机构地区：[1]诚邦生态环境股份有限公司,杭州310008 [2]齐齐哈尔大学建筑与土木工程学院,黑龙江齐齐哈尔161006

出　　处：《齐齐哈尔大学学报（自然科学版）》2023年第6期77-83,94,共8页Journal of Qiqihar University(Natural Science Edition)

基　　金：齐齐哈尔大学横向课题“辅助胶凝材料对废弃混凝土再生性能影响的研究”(220122222019);2021年度省高等教育教学改革一般项目“第二课堂课程思政沉浸式教学模式研究”(SJGY20210965)。

摘　　要：再生混凝土力学性能较差,无法广泛应用,在预先浸泡再生骨料的基础上,将辅助胶凝材料纳米硅溶胶(1%,3%, 5%)与粉煤灰(10%, 15%, 20%)复合掺入再生混凝土中制备了改性再生混凝土。通过抗压强度、劈裂抗拉强度、坍落度试验探究了辅助胶凝材料对再生混凝土综合使用性能的影响;并在微观层次上揭示了辅助胶凝材料对再生混凝土性能影响的作用机理。结果表明,两种材料复合掺入后的协同作用使再生混凝土的力学性能、工作性能得到了全面提升,经试验测得纳米硅溶胶与粉煤灰的最佳复掺量分别为3%, 15%,其90 d抗压强度和劈裂抗拉强度最多提升50.5%, 73.6%,坍落度保持在165 mm左右。微观表征显示复掺两种材料加快了水泥水化反应,降低了水泥浆体的钙硅比,并由此增加了C-S-H凝胶含量;絮凝状C-S-H凝胶紧密包裹着水化产物,填充了混凝土内部的孔隙和裂缝,优化了界面过渡区结构,再生混凝土的强度得到显著提升。In view of the problem that the mechanical properties of recycled concrete are poor and can not be widely used,based on the pre-soaked recycled aggregate,the supplementary cementitious material nano-silica(1%,3%,5%)and fly ash(10%,15%,20%)were mixed into recycled concrete to prepare modified recycled concrete.The influence of supplementary cementitious materials on the comprehensive performance of recycled concrete was investigated by compressive strength test,splitting tensile strength test and slump test.At the micro level,the mechanism of the influence of auxiliary cementitious materials on the performance of recycled concrete is revealed.The results show that the mechanical properties and working performance of recycled concrete are improved by the synergistic effect of the two materials.The optimum composite content of nano-silica and fly ash is 3%and 15%respectively.The 90 d compressive strength and splitting tensile strength are increased by 50.5%and 73.6%at most,and the slump is maintained at about 165mm.Microscopic characterization showed that the two materials accelerated the hydration reaction of cement,reduced the calcium-silicon ratio of cement paste,and thus increased the C-S-H gel content.The flocculated C-S-H gel tightly encapsulates the hydration products,fills the pores and cracks inside the concrete,optimizes the structure of the interfacial transition zone,and significantly improves the strength of the recycled concrete.

关 键 词：再生混凝土 辅助胶凝材料 纳米硅溶胶 粉煤灰 力学性能 

分 类 号：TU528[建筑科学—建筑技术科学]