摘要
采用气冻水融的慢冻法冻融循环机制,通过冻融前后的力学强度、微观形貌分析,对可再分散沥青粉末(EAP)、醋酸乙烯酯-乙烯共聚物(VAE)胶粉改性水泥砂浆进行抗冻性研究,对比在不同掺量、不同循环次数下2种可再分散聚合物粉末对砂浆抗冻性能的改善效果。结果表明:聚合物可在水泥砂浆内部形成膜状结构,提高防水性能,从而能明显提高水泥砂浆的抗冻性能,尤其是200次冻融循环以上的长期抗冻性。冻融循环对聚合物水泥砂浆抗折强度的破坏程度大于对水泥砂浆抗压强度的破坏程度,且在冻融循环早期,聚合物砂浆不会出现严重的结构破坏。在相同掺量下,EAP对水泥砂浆抗冻性能的改善效果优于VAE胶粉,EAP的最佳掺量为10%,VAE胶粉掺量的增大不利于冻融循环后力学强度的保持,但与空白砂浆相比保持效果更好。
By using the slow freezing and thawing cycle mechanism of air freezing and water thawing,and analyzing the mechanical strength and microstructure before and after freezing and thawing,study the frost resistance of cement mortar modified with emulsified asphalt powder(EAP)and ethylene-vinyl acetate copolymer(VAE)adhesive powder.The improvement effect of two re-dispersible polymer powders on the frost resistance of the mortar was compared at different dosages and cycles.The results show that polymers can form a membranelike structure inside the cement mortar,improve its waterproof performance,and significantly improve the frost resistance of the cement mortar,especially the long-term frost resistance after more than 200 freeze-thaw cycles.The degree of damage to the flexural strength of polymer cement mortar caused by freeze-thaw cycles is greater than the degree of damage to the compressive strength of cement mortar,and in the early stages of freeze-thaw cycles,polymer mortar will not experience serious structural damage.At the same dosage,the improvement effect of EAP on the frost resistance of cement mortar is better than that of VAE adhesive powder.The optimal dosage of EAP is 10%.Increasing the VAE adhesive powder dosage is not conducive to maintaining the mechanical strength after freeze-thaw cycles,but it has a better retention effect compared to blank mortar.
出处
《混凝土世界》
2023年第7期32-39,共8页
China Concrete
基金
天津市科技计划项目“超高韧性水泥基材料的技术开发和应用技术研究”(22YFFCYS00070)。
关键词
可再分散沥青粉末
可再分散乳胶粉
水泥砂浆
抗冻性
微观形貌
Re-dispersible asphalt powder
re-dispersible latex powder
cement mortar
frost resistance
microscopic morphology
