再生微粉颗粒级配对水泥凝胶体微观结构及强度的影响  

Effect of particle size distribution of recycled concrete powders on microstructure and strength of cement gel

作　　者：李滢[1] 康晓明 陈曦 代大虎[1] LI Ying;KANG Xiaoming;CHEN Xi;DAI Dahu(School of Civil Engineering,Qinghai Provincial Key Laboratory of Energy Saving Building Materials and Engineering Safety,Qinghai University,Xining 810016,China)

机构地区：[1]青海大学土木工程学院,青海省建筑节能材料与工程安全重点实验室,青海西宁810016

出　　处：《中国粉体技术》2022年第3期107-115,共9页China Powder Science and Technology

基　　金：国家自然科学基金项目,编号:51668025;青海省科学技术厅基础研究计划项目,编号:2017-ZJ-787。

摘　　要：基于Andreasen颗粒紧密堆积理论,探究再生微粉的颗粒级配对水泥凝胶体微观结构及强度的影响。将经过不同时间球磨的再生微粉以相同取代率掺入水泥砂浆中,考察水泥凝胶体中粉体材料的颗粒粒径分布变化与砂浆强度、水泥石孔隙结构及微观形貌的变化关系。结果表明:随着粉磨时间的增加,水泥凝胶体中粉体材料的颗粒级配得到改善,小于10μm的颗粒数量不断增加,这部分超细颗粒用于砂浆中可以填充到水泥浆体的孔隙中,改善水泥凝胶体的微观结构。采用球磨30 min的再生微料制备的砂浆比未经粉磨再生微粉的砂浆总孔隙率增加18.2%,而平均孔径降低51.9%,小于20 nm的无害孔的数量增加25%,孔结构得到改善,水泥石结构趋于密实,砂浆28 d后抗压强度达到43.9 MPa。By using the Andreasen theory of the dense packing powder,the effect of the particle size distribution of the recycled concrete powders(RCP)on microstructure and strength of cement gel was discussed in this paper.The RCP powders were milled in different time and incorporated into the cement mortar in the same substitution to investigate the relationship between particle size distribution of powder materials in cement gels and mortar strength,cement stone pore structure and micro-morphology.It is demonstrated that with the grinding time increases,the particle gradation of the powder material in the cement gel is improved,the content of particles with the size under 10μm is continuously increasing,and it can exert a good filling effect after being used in mortar,and improve the microstructure of cement gel.The total porosity of mortar prepared with RCP-30 increased by 18.2%compared with the mortar by using unscrupulous RCP powders,while the average pore size decreased by 51.9%,the harmous holes with the diameter under 20 nm increased by 25%,and the pore diameter was gradually refined.The pore structure has been improved and the structure of cement paste tends to be density,and the mortar 28 d compressive strength reached 43.9 MPa.

关 键 词：再生微粉 颗粒级配 紧密堆积 孔结构 

分 类 号：TU528.041[建筑科学—建筑技术科学]