防冻剂与早强剂对硫铝酸盐水泥负温水化性能的影响

Effects of Antifreeze and Early-Strength Agent on Hydration of Sulphoaluminate Cement under Sub-Zero Temperature

通过力学性能测试、超声波传播速度测试、压汞法(MIP)测试、热重(TG)分析、X射线衍射(XRD)分析以及扫描电子显微镜(SEM)分析,研究了不同防冻剂与早强剂对硫铝酸盐水泥(SAC)砂浆在无预养的恒负温(-20℃)条件下,养护7 d与28 d后的强度、微观结构以及水化产物的影响规律。结果表明:无机防冻剂硝酸钙与早强剂硫酸铝、三乙醇胺的复合促进了SAC的水化和微结构的发展,使砂浆强度提高;有机防冻剂尿素与硝酸钙的复合延缓了SAC的水化和微结构的发展,使砂浆强度降低;较低水灰比的砂浆表现出更密实的微结构与更高的强度。超声波传播速度可表征砂浆升温过程中微结构的发展,与砂浆强度具有一定的相关性。

The effects of different antifreeze and early-strength agent on strength,microstructure and hydration products of sulphoaluminate cement(SAC)mortar curing at-20℃for 7 d and 28 d without pre-curing were investigated.Mechanical property test,ultrasonic wave velocity test,mercury intrusion porosimetry(MIP)test,thermogravimetric(TG)analysis,X-ray diffraction(XRD)analysis and scanning electron microscope(SEM)analysis were used.The results show that,the combination of inorganic antifreeze calcium nitrate with early-strength agents aluminum sulfate and triethanolamine promote the SAC hydration and microstructure development,which improve the mortar strength.The combination of organic antifreeze urea and calcium nitrate delays the SAC hydration and microstructure development,which reduce the mortar strength.Mortar with lower water-cement ratio show denser microstructure and higher strength.Ultrasonic wave velocity can characterize the microstructure development of mortar during heating process,which has a certain correlation with mortar strength.