粉煤灰对水下不分散混凝土性能的影响

Influence of Fly-ash on Undispersed Concrete under Water

通过粉煤灰对水下不分散混凝土性能影响的试验得出:粉煤灰能显著地改善水下不分散混凝土的流动性,30%的粉煤灰掺入量为一敏感点,对应的坍落度及坍扩度最大,在此值左右,拌合物的坍扩度损失值会发生不同的变化趋向,这也影响着水下不分散混凝土的抗分散性,对水、陆强度影响也较大,但在絮凝剂的共同作用下呈现微膨胀,能显著地提高不分散混凝土的抗渗性。对此,根据掺粉煤灰的复合胶凝材料浆体所形成的分散絮凝结构进行了机理分析,综合得出粉煤灰最适宜掺量为30%的结论。这些试验结果及理论分析对粉煤灰在高性能水下不分散混凝土中的应用具有一定的指导作用。

The following conclusions are obtained through experiment about influence of fly-ash on the undispersed under-water concrete properties. Fly-ash can improve the fluidity remarkably. The dosage （30%） of fly-ash is a turning point of concrete slump and collapse expansion, where the values both reach the highest. Around this point, there are different tendencies for collapse expansion loss, which affects on anti-dispersion property and the strength in water and on earth of undispersed under-water concrete. When the flocculant was also added to, micro expansion appears which is beneficial to increase the impermeability of concrete. Based on the mechanism analysis of dispersed flocculated structure formed by complicated gel materials with fly-ash, 30% is the optimum of fly-ash in this system. These achievements and analysis have a significant guidance for the development and application of undispersed under-water concrete.