硼掺合料对水泥浆体性能的影响

研究了不同含硼添加剂对水泥浆体凝结时间、抗压强度、抗折强度、结合水含量及碱度的影响,并采用XRD和SEM测试手段分析了硬化浆体微观结构,着重考察了硼元素的引入方式对水泥水化性能的影响。研究表明:硼砂、硼酐及硼玻璃粉对水泥浆体性能的影响存在很大差异。硼砂具有明显的缓凝作用;硼酐稍延缓了水泥的凝结时间,但严重影响了水泥石的力学性能,主要可能是硼酐中可溶性硼与水泥水化后的钙离子形成致密的水化硼酸钙膜,覆盖在水泥颗粒表面,阻止了水泥颗粒与外部溶液的接触,使水泥水化反应无法正常进行;而硼玻璃粉对水泥的凝结时间和力学性能均不存在不良影响。

Research of Boron Admixtures Influence to Cement Paste

The setting time,compressive strength,flexural strength,content of bound water and alkalinity of cement paste introduced some different boron admixtures were investigated.The microstructure of hardened paste were studied by X-Ray Diffraction and scanning electron microscope.Furthermore,especially the property of cement hydration was affected by ways of introduced boron element were analyzed.Results indicate that different effects of the performances of cement paste affected by borax,boron anhydride and boron glass powder.Borax has obvious retarding action;Boron anhydride delays the setting time slightly,but has serious impact on the mechanical properties of cement,the main reason is that the surface of cement particles were covered by calcium borate film formed by soluble boron of boron anhydride and calcium ion brought by cement hydration,and the contact of the cement particles and external solution were prevented,in result that the cement hydration reaction is not normal response.While the setting time and mechanical properties of cement hardly have adverse effects through boron glass powder.