机制砂石粉含量对高强水泥砂浆流变学性能的影响

Effects of micro-fines on rheological properties of manufactured-sand high strength mortar

采用Brookfield流变仪测试机制砂中石粉含量对高强机制砂砂浆流变性能的影响,并结合相应机制砂混凝土工作性能的测试,探讨了砂浆流变学参数与混凝土坍落度和扩展度的关系。试验结果表明:当机制砂中石粉含量低于5%时,石粉含量变化对砂浆工作性无不利影响;但当石粉含量大于5%时,随机制砂中石粉含量的提高,砂浆的塑性黏度和屈服应力增大,显著劣化砂浆的工作性能。当石粉等质量取代水泥作矿物掺合料时,适量的石粉可以改善砂浆的流变性能。试验结果还表明:机制砂砂浆的流变学参数与混凝土工作性能测试结果变化趋势具有较强的相关性,可以指导机制砂混凝土的组成设计。

The effects of micro-fines content of high strength manufactured-sand mortar rheological properties are tested by Brookfield rheometer.It is discussed the relationship of rheology parameters and concrete slump combined with concrete workability test.The result shows that micro-fines have no adverse effect on mortar workability when the micro-fines content is below 5%.The mortar plastic viscosity and yield stress increase,and workability of mortar degrade significantly when the micro-fines content is above 5%.A reasonable amount of micro-fines can improve the rheological properties of the mortar,When the powder quality to replace admixtures of cement.The test re-sults also show that the rheological parameters of manufactured-sand mortar and concrete workability test results change trend have strong correlation.Rheological test can guide mechanism of sand concrete design.