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以坍落度损失率及扩展度损失率为主要考察指标,采用正交法制备出超长保坍湿喷混凝土用聚羧酸系减水剂,并对该减水剂进行了不同掺量、不同水泥品种、不同胶凝材料用量及不同环境温度下的长时间保坍性能的评价。结果表明,该减水剂随掺量的提高,坍落度及扩展度的保持性能得到显著的提升,与不同水泥具有相对广泛的高保坍适应性,但该减水剂需要一定用量的胶凝材料才能赋予湿喷混凝土长时间的高保坍性能;环境温度对该减水剂的长时间保坍性能存在一定的影响,但该减水剂依然可以在40℃的环境温度下实现超长时间(4~6 h)的保坍,满足长时间泵送施工的技术要求。
Taking the rate of loss of slump and the rate of loss of expansion as the main indexes, the polycarboxylate superplasticizer for the over-long slump wet-sprinkled concrete was prepared by orthogonal method. The superplasticizer was treated with different dosage, Evaluation of different cement varieties, dosage of different cementitious materials and long slump performance under different ambient temperature. The results show that with the increase of dosage, the retention of slump and extension of the superplasticizer can be improved remarkably. Compared with different cement, the superplasticizer has a wide range of adaptability to high slung collapse. However, the superplasticizer needs a certain amount of gelling Material can give long-term high-slump performance of wet-sprayed concrete. The ambient temperature has a certain influence on the long-term slump performance of the water-reducing admixture, but the superplasticizer can still achieve ultra-long time under the ambient temperature of 40 ℃ 4 ~ 6 h) Paul collapse, to meet the long-term pumping construction of the technical requirements.