碳化混凝土孔隙结构与Autoclam气体渗透性能的关联性研究  

On the Relationship Between Pore Structure and Gas Permeability from Autoclam Test in Carbonated Concrete

作　　者：张铖 王玲 姚燕 史鑫宇 ZHANG Cheng;WANG Ling;YAO Yan;SHI Xinyu(State Key Laboratory of Green Building Materials,China Building Materials Academy Co.,Ltd.,Beijing 100024,China)

机构地区：[1]中国建筑材料科学研究总院有限公司,绿色建筑材料国家重点实验室,北京100024

出　　处：《材料导报》2023年第8期46-50,共5页Materials Reports

基　　金：国家自然科学基金(51961135202)。

摘　　要：将C30混凝土试件在20%(体积分数)CO_(2)中加速碳化至不同龄期,采用Autoclam测试系统和压汞法(MIP)测试碳化混凝土的空气渗透系数(kAu)及孔隙结构参数,通过灰色关联分析(GRA)研究了二者的关系。结果表明:随碳化时间延长,混凝土的kAu呈指数式增长,混凝土孔隙率、特征孔径和孔隙连通度也增大,孔径小于200 nm孔的体积占比逐渐减小,200~1 000 nm孔的体积占比逐渐增大,小于1 000 nm孔的体积占比基本不变。GRA结果显示,与碳化混凝土kAu关联度最高的三个孔隙结构参数是:50~200 nm孔的体积占比(γi=0.932)、孔隙连通度(γi=0.907)和孔隙率(γi=0.888),回归建立了kAu与这三个参数之间的线性关系模型,为后期利用kAu建立混凝土寿命预测模型奠定了基础。The C30 concrete specimens were exposed in a 20vol%CO_(2)atmosphere at different ages for the accelerated carbonation test.The carbonated concrete's gas permeability coefficient(k Au)and pore structure parameters were measured by the Autoclam test system and the mercury intrusion porosimetry(MIP).The relationship between k Au and pore structure parameters was studied by grey correlation analysis(GRA).The test results showed that the air permeability coefficient of the carbonated concrete increased exponentially with the increase of exposure time.The porosity,characteristic pore size and pore connectivity of the carbonated concrete increased with the exposure time as well.For the change of pore distribution with the exposure time,the volume ratio of pores smaller than 200 nm decreased,the volume ratio of pores with the diameter of 200-1000 nm increased,and the volume ratio of pores larger than 1000 nm was unchanged.The GRA results showed that the pore structure parameters with the highest correlation with the k Au are the volume ratio of 50-200 nm pores,pore connectivity,and porosity.The grey correlation coefficients of the above three parameters are 0.932,0.907 and 0.888,respectively.The linear relation model between k Au and the three parameters was established by regression,laying the foundation for future work on establishing a service life prediction model based on gas permeability coefficient.

关 键 词：混凝土 加速碳化 孔隙结构 空气渗透系数 灰色关联分析 

分 类 号：TU528[建筑科学—建筑技术科学]