对四种聚羧酸系高性能减水剂进行了扩链剂改性研究,并优化出最佳改性工艺。结果表明,改性后的聚羧酸系高性能减水剂A对水泥的分散性能仅起到抵消缓释作用,B、C、D对水泥的分散性能有很大的提高,尤其是对保坍性能较差的减水剂；改性后的减水剂对混凝土的流变性能与水泥净浆流动度的变化规律基本一致,对混凝土的含气量、抗压强度、渗透性能和外观质量有了明显改善,而且降低了成本；同时,从分子链结构搭配的角度分析了扩链剂的改性机理。%Four kinds of polycarboxylic high performance water reducer were modified by chain extender, and the best modification technology was optimized. The results show that the modified polycarboxylic high performance water re-ducer A only plays release effect on the dispersiveness of cement, while the modified polycarboxylic high performance wa-ter reducer B, C and D can greatly improve the dispersiveness of the cement, especially to the water reducer with poor slump performance. Furthermore, the influence of the modified water reducer on rheological properties of concrete has the same rule as that of the modified water reducer on the fluidity of cement paste. In addition, gas content, compressive strength, permeability and appearance quality of the concrete are obviously improved and the cost is also reduced. Finally, the modification mechanism of chain extender is analyzed from the point of the molecular chain structure.
展开▼
