地铁管片混凝土快分散型聚羧酸减水剂的开发与应用

Development and application of rapidly disperse polycarboxylate superplasticizer for subway concrete segment

采用净浆流动度、流变性能、PCE的吸附性能对开发的减水剂进行分散性能评价,优选出快分散型聚羧酸减水剂。结果表明:随时间延长,PCE8流动度降低速率逐渐变缓,PCE6-2的流动度在20 min后加速损失;同掺量和低剪切速率下PCE6-1、PCE6-2的黏度总是高于PCE8,高剪切速率下PCE6-2的黏度低于PCE6-1、PCE8,在实际管片生产中,高频振动时PCE6-2的黏度迅速降低,有利于气泡排出;初始同流动度前30 min时PCE6-1、PCE6-2的黏度始终低于PCE8,30 min后PCE6-2黏度迅速上升,到60 min时PCE6-2的黏度高于PCE8、PCE6-1;PCE8的吸附量随着时间的延长而增加,而PCE6-1在10~20 min内迅速达到较高的吸附量,随后吸附量缓慢的增长,PCE6-2在前20 min内快速吸附达到最高峰,之后缓慢减少。采用快分散型聚羧酸减水剂在北京房山成都管片厂工程进行了成功的应用。

The degree of paste fluidity,rheological properties,and adsorption performance tests were used to evaluate the dispersion properties of PCE,and a rapidly disperse polycarboxylate superplasticizer was selected.The results show that with the increase of time,the rate of decrease of PCE8 fluidity gradually decreases,and the fluidity of PCE6-2 accelerates the loss after 20 minutes.The viscosity of PCE6-1 and PCE6-2 is always higher than that of PCE8 at the same dosage and low shear rate.The viscosity of PCE6-2 at high shear rate is lower than that of PCE6-1 and PCE8.In the segment production,the viscosity of PCE6-2 rapidly decreases at high frequency vibration,which is beneficial to the elimination of bubbles.For the same initial fluidity,the viscosity of PCE 6-1 and PCE6-2 was always lower than that of PCE8 in the first 30 minutes,and the viscosity of PCE6-2 rapidly increased after 30 minutes.At 60 minutes,the viscosity of PCE6-2 was higher than that of PCE8 and PCE6-1.The adsorption capacity of PCE8 increased with time,while PCE6-1 reached a higher adsorption capacity within 10~20 min,and then the adsorption amount slowly increased.PCE6-2 rapidly adsorbed in the first 20 min to reach the highest peak,and then slowly decreased,and rapidly disperse polycarboxylate superplasticizer has been successfully applied in Beijing Fangshan Chengdu Segmental Plant Project.