引气水泥砂浆流变性试验研究

Experimental Study on Rheological Property of Air-entrained Cement Mortar

采用砂浆扭矩转速测试仪研究了4种引气剂对水泥砂浆流动度、含气量和流变性的影响。结果表明,引气水泥砂浆可视为宾汉姆体。引气气泡对浆体的流动性可以产生调节,黏度较大时,引气气泡可以降低浆体的黏度,改善流动性;反之,则引气气泡对浆体的流动性产生抑制。不同流态水泥砂浆的含气量均随引气剂掺量的增大而增大。低掺量引气剂时,高流态砂浆含气量高于低流态砂浆含气量;高掺量引气剂时,结果相反。在特定引气剂掺量范围内,砂浆塑性黏度提高,屈服应力降低。随着引气剂掺量增大,砂浆塑性黏度先增大后减小,屈服应力先减小后增大。

The effects of 4 air-entraining agents on fluidity, air content and rheological property of cement mortar are studied by means of mortar torque speed tester. The result shows that （ 1 ） air-entrained cement mortar can be regarded as Bingham body. （2） The fluidity of cement mortar can be adjusted by air-entrained bubbles. With higher viscosity, air-entrained bubbles can reduce the viscosity of mortar and improve the fluidity, while it will be restrained when the viscosity is lower. （3） The air content of different kinds of flow state mortar increases with the increasing dosage of air-entraining agent. When the dosage of air-entraining agent is lower, the air content of high flow state mortar is larger than that of lower flow state one, while the dosage of air-entraining agent is larger, the result is opposite. （4） Within a certain range of air entraining agent content, plastic viscosity of mortar rises and yield stress decreases. （5） With the improvement of airentraining agent dosage, the plastic viscosity of mortar rises first and then decreases, while yield stress reduces first and then increases.