半浸泡硫铝酸盐水泥混凝土蒸发区孔结构变化  

Pore Structure Development of Evaporation Zone of Partially Immersed Calcium Sulphoaluminate Cement Concrete

作　　者：刘赞群[1] 周蕴婵 胡文龙 彭嘉伟 LIU Zanqun;ZHOU Yunchan;HU Wenlong;PENG Jiawei(School of Civil Engineering,Central South University,Changsha 410075,China;Changjiang Institute of Survey,Planning,Design and Research,Wuhan 430000,China)

机构地区：[1]中南大学土木工程学院,长沙410075 [2]长江勘测规划设计研究有限责任公司,武汉430000

出　　处：《材料导报》2023年第3期161-165,共5页Materials Reports

基　　金：国家自然科学基金(51378508)。

摘　　要：硫铝酸盐水泥水化需水量大、水化速度快,凝结硬化后留下的大量未水化水泥在后期继续水化生成钙矾石,影响混凝土的孔结构变化和力学性能发展。用半浸泡方式模拟半掩埋混凝土实际工况,运用背散射电镜和核磁共振等微观测试手段,研究了水灰比为0.35、0.45和0.55的硫铝酸盐水泥混凝土半浸泡35 d、70 d和130 d后蒸发区孔结构和混凝土抗压强度变化规律,结果表明:水灰比为0.35和0.45的混凝土孔隙率呈现先增大后降低再增大的变化特点;水灰比为0.55的混凝土孔隙率呈现先降低后增大的变化特点。研究表明:硫铝酸盐水泥凝结硬化后水化生成的钙矾石会产生结晶膨胀和填充密实两种效应,共同影响硫铝酸盐水泥混凝土孔结构变化。The hydration of calcium sulphoaluminate(CSA)cement needs a large amount of water and hydrates quickly.A large amount of unhydrated cement will be left,and ettringite will be further formed in the harden concrete,influencing the development of pore structure and mechanical properties of concrete.In this paper,the field conditions of half-immersed concrete were simulated by half immersion method.The pore structures of evaporation zone of CSA cement concretes with the water-cement ratio of 0.35,0.45 and 0.55 were studied after half-immersion for 35 d,70 d and 130 d by means of nuclear magnetic resonance(NMR)and scanning electron microscope(BSE mode).The test results showed that the porosities of concretes with the water-cement ratio of 0.35 and 0.45 increased,then decreased,and increased again;the porosity of concrete with the water-cement ratio of 0.55 declined,and then increased.The test results supported that the pore structure development of CSA cement concrete was controlled by the combined effects of crystallization expansion and pore refinement due to the ettringite formation after hardening.

关 键 词：半浸泡 硫铝酸盐水泥混凝土 孔结构 钙矾石 结晶 

分 类 号：TU528.1[建筑科学—建筑技术科学]