摘要
为了减少混凝土因收缩开裂引起的混凝土结构耐久性问题,研制了一种减水率高、水泥适应性好的减缩型聚羧酸系减水剂。首先使用丙烯酸、新戊二醇和携水剂,在阻聚剂和催化剂作用下制备了一种酯类功能单体;然后将酯类功能单体与异戊烯醇聚氧乙烯醚、丙烯酸及一缩二丙二醇等单体,在氧化-还原复合引发剂和链转移剂作用下进行共聚,合成了减缩型聚羧酸系减水剂TX-938。合成样品的性能试验结果表明:TX-938在分散性能及保持能力上与标准型聚羧酸系减水剂TX-50H基本相同,且具有较好的水泥适应性;TX-938在掺量为2.5%时可以将溶液表面张力从72.3 m N/m降低至31.6 m N/m;掺2种聚羧酸系减水剂的水泥胶砂试件的28 d干燥收缩率分别较空白样降低了10.5%和29.1%,TX-938更能显著降低水泥胶砂的干燥收缩;掺2种聚羧系减水剂的混凝土初凝后72 h收缩率分别为452×10^(- 6)和399×10^(- 6),掺TX-938的混凝土收缩率为掺TX-50H的88%,混凝土28 d掺TX-938收缩率仅为空白样的35.6%,比掺TX-50H降低1/2倍还多;TX-938的减水率达到29.4%,混凝土不同龄期强度也没有负面影响。
To solve the durability of structures caused by shrinkage and crack of concrete,we prepared an shrinkagereducing polycarboxylate superplasticizer（ PS） with high water-reducing rate and good cementitious compatibility.Firstly,an ester macromonomer was prepared by using acrylic acid,neopentyl glycol and water-carrying agent in association with polymerization inhibitor and catalyzer. Then,the shrinkage-reducing PS of TX-938 was synthesized by using the ester monomer,isoamyl alcohol polyoxyethylene ether,acrylic acid and dipropylene glycol with the combined effect of the oxidation-reduction initiator and chain-transferring agent. The performance that we tested shows that,as for cement dispersion property and adaptability,the shrinkage-reducing PS of TX-938 is almost equal to TX-50 H,which is a kind of normal PS; moreover,TX-938 can significantly decrease the surface tension from 72. 3 m N / m（ without TX-938） to 31. 6 m N/m with the blending ratio of 2. 5%; then,the drying shrinkage of mortar blended with TX-50 H and TX-938 decreases by 10. 5% and 29. 1% respectively when compared with that of mortar without PS; 72 hours after initial set,the drying shrinkage of concrete is 452 × 10- 6and 399 × 10- 6respectively,in other words,the drying shrinkage of concrete with TX-938 was only 88% of that of concrete with TX-50 H,and the 28 d drying shrinkage of concrete with TX-938 is only 35. 6% of that of concrete without PS,less than 50% of that of concrete with TX-50H; finally,the water-reducing rate of TX-938 is up to 29. 4% and TX-938 has no negative effect on compressive strength of concrete at different ages.
出处
《长江科学院院报》
CSCD
北大核心
2015年第12期134-138,共5页
Journal of Changjiang River Scientific Research Institute
基金
水利部科技推广计划项目(TG1424)
关键词
减缩型
聚羧酸系
减水剂
合成
混凝土强度
混凝土收缩率
shrinkage-reducing type
polycarboxylate
superplasticizer
synthesis
strength of concrete
shrinkage of concrete
