硅藻土改性再生骨料混凝土的抗离子侵蚀性能  

Resistance of recycled aggregate concrete to ion ingress by using diatomaceous earth

作　　者：赵亚婉 张鸿儒 张宝明 何炳坚 白银战 ZHAO Yawan;ZHANG Hongru;ZHANG Baoming;HE Bingjian;BAI Yinzhan(CCCC First Highway Consultants Co.,Ltd.,Xi'an 710065,China;College of Civil Engineering,Fuzhou University,Fuzhou 350116,China;School of Advanced Manufacturing,Fuzhou University,Quanzhou 362251,China;School of Civil Engineering and Architecture,Wenzhou Polytechnic,Wenzhou 325000,China;China Harbour Engineering Co.,Ltd.,Beijing 100000,China)

机构地区：[1]中交第一公路勘察设计研究院有限公司,陕西西安710065 [2]福州大学土木工程学院,福建福州350116 [3]福州大学先进制造学院,福建泉州362251 [4]温州职业技术学院建筑工程学院,浙江温州325000 [5]中国港湾工程有限责任公司,北京100000

出　　处：《混凝土》2024年第7期141-148,共8页Concrete

基　　金：陕西省住房和城乡建设厅科研开发计划项目(2021-K49);国家自然科学基金面上项目(52178121);中交第一公路勘察设计研究院有限公司科技创新基金(KCJJ2021-24)。

摘　　要：采用硅藻土部分取代水泥制备再生骨料混凝土(RAC),研究硅藻土内掺法对RAC抗离子(氯离子、硫酸根离子)侵蚀性能的改善效果及机理。试验结果表明,硅藻土可在水泥水化进程中发挥成核效应和火山灰效应,促进水泥水化,并改善界面过渡区水化产物结构,使界面过渡区更致密、厚度减小,使新砂浆水泥基体孔结构细化、大孔减少,从而减少RAC中离子侵蚀通道,减缓氯离子、硫酸根离子在RAC中的浓度积累。内掺硅藻土还提升了RAC细观尺度上各材料相(新、老砂浆及新界面过渡区)的显微硬度,减缓各材料相在硫酸根离子侵蚀下的性能劣化,从而使宏观尺度上RAC在硫酸盐侵蚀下力学性能劣化速度和程度显著降低。The cement was partially replaced by diatomaceous earth(DE)to prepare recycled aggregate concrete(RAC)for the purpose of improving the resistance of RAC to the ingress of chloride ions and sulfate ions.Test results show that DE could promote cement hydration by inducing the nucleation effect and pozzolanic effect,which can improve the microstructure of the hydration products in the interface transition zone(ITZ)to make the ITZ denser and thinner.DE could also make the pores of the new cement matrix finer and reduce the proportion of the large pores.In this way,the channels for ion ingress erosion in RAC decreased so the accumulation of chloride ions and sulfate ions in RAC was slower compared to the reference RAC.The addition of DE also enhanced the microhardness of the mesoscopic material phases(the new/old cement mortars and the new ITZ),so the degradation of these material phase under the external sulfate attacks was significantly depressed.As a result,the deterioration ofthe mechanical properties ofRAC under sulfate attacks at the macro scale was significantly reduced.

关 键 词：再生骨料混凝土 硅藻土 离子侵蚀 界面过渡区 

分 类 号：TU528.041[建筑科学—建筑技术科学]