水膜厚度对水泥净浆流动性能影响试验研究

Experimental research on the influence of water film thickness on the flow performance of cement paste

通过控制不同水固比和减水剂掺量下的25组测量试验,基于湿测法、计算式计算和截锥圆形模具分别测量水泥净浆的填充密度、水膜厚度和扩展度,分析水固比和减水剂掺量对填充密度、水膜厚度和扩展度的变化规律和内在联系,结果表明:在试验过程中,水固比的增加会提高水泥净浆的填充密度和水膜厚度,但增长速率呈衰减趋势,其中出现最佳填充密度;减水剂掺量会改善颗粒表面作用力,发生絮凝水释放现象,从而增加填充密度和水膜厚度,但减水剂的加入使得水膜厚度存在一快速增长阶段后趋于平缓,且分级递增减水剂掺量对于水膜厚度增量影响表现为衰减趋势;对于水泥净浆的流动性,减水剂的影响程度要强于水固比,且流动性与水膜厚度成良好相关性,在实际工程中可通过确定最佳水固比和适当添加减水剂来提高水泥净浆的流动性。

By controlling 25 sets of measurement tests under different water-solid ratios and water-reducing agent content,the filling density,water film thickness and expansion of the cement paste were measured based on the wet measurement method,formula calculation and truncated cone circular mold,and the water was analyzed.The relationship between the solid ratio and the amount of water-reducing agent to fill density,water film thickness and expansion degree changes and internal relations,the results show that in the test process,the increase in water-solid ratio will increase the filling density and water film thickness of the cement paste.But the growth rate is attenuating,and the optimal filling density appears.The amount of water reducing agent will improve the surface force of the particles,and the phenomenon of flocculating water will be released,thereby increasing the filling density and the thickness of the water film,but the addition of the water reducing agent makes the water.The film thickness tends to be flat after a rapid growth stage,and the influence of the graded increasing water reducing agent content on the increase of the water film thickness shows a declining trend.For the fluidity of the cement paste,the impact of the water reducing agent is stronger than that of the water solid.The fluidity has a good correlation with the thickness of the water film.In actual projects,the fluidity of the cement paste can be improved by determining the best water-solid ratio and adding water-reducing agents appropriately.