评价减水剂性能的新方法——砂浆坍落扩展度  

A NEW APPROACH OF EVALUATING SUPERPLASTICIZERS BY MORTAR SLUMP FLOW TEST

作　　者：徐永模 彭杰[2] 赵昕南[3] 

机构地区：[1]中国建筑材料工业协会,北京100831 [2]中国建筑材料科学研究院,北京100024 [3]北京工业大学,北京100022

出　　处：《硅酸盐学报》2002年第z1期124-130,共7页Journal of The Chinese Ceramic Society

摘　　要：混凝土减水剂的减水率、流化性能和最佳掺量等性能一般用水泥浆或混凝土坍落流动性能试验方法评价。应用砂浆坍落扩展度试验建立了全分散状态下,饱和掺量概念和确认达到饱和掺量的3种典型行为:泌水环,扩展度不变和扩展度降低。通过全分散状态的确定,比较了不同减水剂的饱和掺量、极限坍落扩展度、泌水性和扩展度随时间的损失等性能,区别了经常混淆的混凝土减水剂饱和掺量和最佳掺量的概念。对比试验研究了3种高效减水剂在饱和掺量和坍落扩展度损失等方面的性能差异,发现饱和掺量随水灰比减小和砂灰比增大而增加。研究表明,砂浆坍落扩展度试验为确定满足混凝土工作性要求的减水剂最佳掺量提供了一个理论上比较完善,试验工作简便可靠、省时省力并且节约材料的有效方法。A new approach of evaluating superplasticizers was established with mortar slump flow test, based on the identification of the complete separation state of cement particles in the mortar. Three typical behaviors were characterized by the saturation dosages reached with a step-wise increase of superplastizers: i.e. a clear bleeding circle, no change in spread values and reduction in spread values. Three superplasticizers are differentiated by the saturation dosage, the maximum spread, the bleeding behavior and the time-effect of the spreading. It is found that the saturation dosage increases with the decrease of water/cement ratio and the increase of sand/cement ratio. The saturation dosages of superplasticizers determined provide a more reliable reference for the determination of the optimum dosages in concretes with different workability requirements. The mortar test is found more convenient, time - saving, low cost and less physical demanding in comparison with concrete slump.

关 键 词：减水剂 砂浆 坍落扩展度 饱和掺量 

分 类 号：TU528[建筑科学—建筑技术科学]