复合防冻剂制备及其应用研究

Preparation and application research of anti-freezing admixture

将硝酸钙、三乙醇胺、二乙醇单异丙醇胺、硝酸钠、三萜皂苷、聚羧酸减水剂与水复配制得新型无氯复合防冻剂FD-20,研究防冻剂在不同使用条件下对混凝土性能的影响,通过SEM对掺入防冻剂混凝土微观形貌进行表征,同时研究了FD-20对抗钢筋锈蚀性能的影响。SEM分析表明,掺入FD-20能促进混凝土在负温环境下的水化反应。试验结果表明:FD-20的掺量为4%时防冻效果最佳,FD-20能显著提高混凝土在负温(-15℃)条件下的早期抗压强度,且不影响后期强度的发展,不会对砂浆中的钢筋造成锈蚀作用;升高入模温度及减小出机坍落度均能明显提高掺FD-20混凝土在负温养护条件下的早期强度;同时,在10℃以下的正温环境中,使用该防冻剂可明显提高混凝土的早期强度。

A new kind of composite chlorine-free anti-freezing admixture FD-20 was prepared by compounding calcium nitrate,triethanolamine,diethanol monoisopropanolamine,sodium nitrate,triterpenoid saponin,polycarboxylate superplasticizer and water.The influence of anti-freezing admixture on the performance of concrete under different using conditions was studied.The microstructure of concrete mixed with anti-freezing admixture was shown by SEM,the effect of FD-20 on the corrosion resistance of reinforced bar was studied.The SEM results show that the addition of anti-freezing admixture can effectively promote the hydration reaction of concrete in negative temperature environment.The test results show that:FD-20 can significantly improve the development of early compressive strength of concrete under negative temperature condition(-15℃),and without affecting the devel-opment of later strength.The best FD-20 dosage is 4%.The early strength performance of concrete under the condition of negative temperature curing can be significantly improved by increasing the mold temperature and reducing the slump under the premise of using the anti-freezing admixture,and the early strength of concrete can also be significantly improved in the normal temperature environment under 10℃.