大掺量粉煤灰水泥砂浆溶蚀强度变化规律  

STUDY ON THE LAW OF STRENGTH EVOLUTION OF HIGH-VOLUME FLY ASH CEMENT MORTAR

作　　者：庞敏 孙振平[3,2] 肖建庄[1,2] 王培铭[3,2] PANG Min;SUN Zhenping;XIAO Jianzhuang;WANG Peiming(School of Civil Engi.,Tongji Univ.,Shanghai 200092,China;School of Materials Science and Engi.,Tongji Univ.,Shanghai 201804,China;Key Laboratory of Advanced Civil Engi.Material of Ministry of Education,Tongji Univ.,Shanghai 201804,China)

机构地区：[1]同济大学土木工程学院,上海200092 [2]同济大学先进土木工程材料教育部重点实验室,上海201804 [3]同济大学材料科学与工程学院,上海201804

出　　处：《低温建筑技术》2018年第6期1-4,10,共5页Low Temperature Architecture Technology

基　　金：十三五国家重点专项课题(2016YFC0701004);国家自然科学基金(51678441);国家自然科学联合基金(U1534207);上海市经信委专项资金项目(沪CXY-2016-012);上海市住建管项目(2017-001-009)

摘　　要：研究了加速溶蚀下纯水泥和粉煤灰用量分别为50%,70%和90%的混合水泥砂浆强度的变化规律,采用XRD测试技术对溶蚀和未溶蚀硬化浆体化学组成进行分析,结合宏观数据进行了机理解释。结果表明,相对于溶蚀前,纯水泥砂浆试件破坏严重,抗折和抗压溶蚀强度均下降显著;而粉煤灰水泥砂浆,抗折强度略有下降,抗压强度反而有所增长,其中粉煤灰掺量为70%时,砂浆抗溶蚀性能最好;相对于未溶蚀试件,纯水泥砂浆强度损失严重,粉煤灰水泥砂浆强度亦有所降低,但强度损失程度相对较低,其变化规律与粉煤灰用量关联不明显;混合水泥中粉煤灰的二次水化,降低了浆体中氢氧化钙(CH)的量,优化了浆体微结构组成,对溶蚀产生了阻碍缓释作用,提高了砂浆抗溶蚀性能。当粉煤灰用量过高时,浆体中CH严重贫乏,不足以满足粉煤灰二次水化的需求,将限制缓释作用的发挥。The mortars of the high-volume fly ash cement(hereinafter referred to as‘fly ash cement’)with 50%,70%and 90%of the amount of fly ash and Portland cement cured 28d,the strength evolution law under accelerated leaching and mechanism of dissolution were studied.With hydration product in the hardened paste of Portland cement and fly ash cement was analyzed.The results show that,after leached,Portland cement mortar specimen damaged seriously,Corrosion corrosion strength decreased seriously regardless of flexural or compressive strength,fly ash cement mortar only a certain degree of flexural strength decreased,but also increased the compressive strength,where the blended cement with 70%fly ash,its mortar anti-corrosion performance is relatively good.Relative to the same age specimen without corrosion,Portland cement mortar,regardless of flexural or compressive strength,corrosion strength loss significantly,the loss of cement strength is relatively low,and associated with the amount of fly ash is not obvious.The addition of fly ash decreases the amount of CH in the paste,optimizes the microstructure of the pastes,and has a certain sustained improvement on anti-corrosion.Secondary hydration of fly ash is essential to release effect,but when the fly ash is added in excess and the CH is seriously deficient in the paste,it will limit the effect of sustained release.

关 键 词：溶蚀 粉煤灰水泥 强度 缓释作用 

分 类 号：TU52[建筑科学—建筑技术科学]