-10℃即时受冻条件下外加剂和掺和料对负温混凝土性能影响

Effects of Chemical and Mineral Admixtures on Negative Temperature Concrete in the Instant Freezing Condition of -10℃

在-10℃即时受冻条件下,采用SK复合防冻剂、粉煤灰、纤维素醚和硅粉配制C30F300混凝土,以研究无预养情况下,化学与矿物外加剂对负温混凝土抗压强度、耐久性能和变形性能的影响.结果表明:在-10℃即时受冻条件下,掺加SK复合防冻剂可配制满足C30F300设计等级的负温混凝土,复掺SK复合防冻剂和矿物掺和料是制备负温混凝土的关键技术.另外,借助X射线衍射(XRD)、压汞法(MIP)、扫描电子显微镜(SEM)等测试方法,对比研究了未掺与掺加SK复合防冻剂水泥净浆的水化过程,阐明了SK复合防冻剂的作用机理;从理论上探讨了SK复合防冻剂、纤维素醚和矿物掺和料对负温混凝土的作用,可以为混凝土配合比设计与施工提供技术参考.

SK antifreeze compound,fly ash,cellulose ether and silica fume were used to prepare C30F300 concrete in the instant freezing condition of-10℃.The effects of chemical and mineral admixtures on compressive strength,durability and deformation performance of negative temperature concrete were investigated when pre-curing is not required.The results show that in the instant freezing condition of-10℃,SK antifreeze compound can be applied to prepare negative temperature concrete that satisfies the design requirements of C30F300.The key technology of preparing negative temperature concrete is adding SK antifreeze compound and mineral admixtures.In addition,the mechanism of SK antifreeze compound is clarified by means of X-ray diffraction(XRD),mercury intrusion porosimetry(MIP)and scanning electron microscope(SEM),which are utilized to compare and observe the hydration process of cement paste with and without SK antifreeze compound.The function of SK antifreeze compound,cellulose ether and mineral admixtures in negative temperature concrete is explored theoretically,which is aimed to provide technical reference to mix design and construction.