摘要
针对高水材料强度相对偏低、成本相对较高的问题,选取粉煤灰和硅粉两种材料作为添加剂,对高水材料进行改性研究。设置添加剂掺量梯度为5%、10%、15%和20%,采用四川大学电子万能试验机和扫描电镜(SEM)两种试验设备,进行添加剂对高水材料力学性质影响试验,探究添加剂对高水材料力学性质及微观结构的影响。试验结果表明,添加剂对高水材料力学性质和微观结构均有较大的影响:1)掺20%粉煤灰和掺10%硅粉均可使高水材料的抗压强度提高到0.36 MPa,与未掺添加剂高水材料相比,强度提高了20%,且能有效提高残余强度。2)添加剂的掺入改变了高水材料钙矾石晶体的发育形貌、直径大小及空间网状结构的致密程度,主要包括以下两个方面:粉煤灰的掺入使晶体形貌由短棒状发展为针棒状,大直径晶体数量增多,绒球状的水化硅酸钙及未反应完的残留物填充在晶体结构孔隙中,使晶体空间结构更为致密;硅粉的掺入使晶体形貌发展为枝网状,水化硅酸钙数量增加,起到了充填孔隙和增加晶体交错搭接牢固性的作用,枝网状的晶体和绒球状的硅酸钙共同形成了致密的网状结构。3)证明了抗压强度的大小是由晶体形貌、直径大小、晶体结构的搭接方式及网状结构的致密性共同影响的。
According to the problem of relatively low strength and relatively high cost of high-water material,choosing fly ash and silica fume as two additives,the properties of modificated high-water material was studied,and the additive content were 5%,10%,15% and 20%,respectively.The internal microstructure and macroscopic properties of high-water material mixed with additives were studied using SEM scanning electric microscopy and computer-controlled electronic universal testing machine.Experimental results showed that additives had a great impact on properties and microstructure.The addition of 20% fly ash or 10% silica fume both could improve the compressive strength to 0.36 MPa and the strength was increased by 20% compared with pure high-water material.Besides,the residual strengths were improved effectively.The morphology,diameter and space mesh structure of high-water material were changed due to fly ash and silica fume addition.The crystal morphology of high-water material mixed with fly ash were dominated by needle bar,and the number of large diameter crystal was increased,the crystal structure's pore was filled with ball-shaped calcium silicate hydrate and residues.The branches morphology of material mixed with silica fume increased the connection of crystals and the compactness of mesh structure.It was proved that the compressive strength was determined by crystal morphology,diameter,lap of the crystal structure and the dense state of lattice structure.
出处
《四川大学学报（工程科学版）》
CSCD
北大核心
2017年第S1期21-26,共6页
Journal of Sichuan University (Engineering Science Edition)
基金
国家自然科学基金煤炭联合基金重点资助项目(51134018
51369001)
关键词
高水材料
改性
粉煤灰
硅粉
抗压强度
微观结构
high-water material
modification
fly ash
silica fume
the compressive strength
microstructure
