SIDE-CHAIN STRUCTURE ON THE POLYCARBOXYLIC ACID TYPE WATER-REDUCING AGENT
Polycarboxylic acid type water-reducing agent is the direction of development ofconcrete water-reducer. This paper aims to expound that the comb-shaped copolymer ofpolycarboxylate are synthesized by different molecular weight of methoxy polyethyleneglycol monomethacrylate (MPEA) and methacrylic acid (MAA). The effects of comb-shapedcopolymer on dispersibility,holding dispersibility,setting time,air-entrained performance,and early strength have also been studied. The results show that molecular weight of MPEAand amount of carboxyl (COO) effect the dispersibility and holding dispersibility; the moreamount of carboxyl (COO),the better holding dispersibility; the more molecular weight ofMPEA,the better dispersibility; the less molecular weight of MPEA,the better holdingdispersibility. Comparing with control,it can delay the setting time from 1h to 7h by addingthe amount of the carboxyl (COO) and from 1h to 3h by modulating the molecular weight ofMPEA. The molecular weight of MPEA effect the air-entrained performance,but there existsa critical molecular weight of MPEA,when less than 1000,the defoaming time shortensquickly,when and more than 1000,the defoaming time increases slowly. With increasingamount of carboxyl (COO) and molecular weight of MPEA,the ability of restraining initialhydration of C3S strengthens,but it has no effect on later hydration.
polycarboxylic water-reducer structures and properties dispersibility holding dispersibility function controlling
MA Baoguo TAN Hongbo LI Liang ZHANG Man
Key Labortory for Silicate Materials Science Engineering of Ministry of Education,Wuhan University of Technology,Wuhan 430070,Hubei,PR China
国际会议
The International Conference on Durability of Concrete Structures(2008年混凝土结构耐久性国际学术会议)
杭州
英文
337-343
2008-11-01（万方平台首次上网日期，不代表论文的发表时间）