Abstract:

In order to prepare mineral admixture with excellent property for concrete,a new type of multi-compo-nent mineral material with large content of fly ash as the substitute was investigated by orthogonal experiments.Without any activator,fly ash,granulated blast furnace slag and some natural mineral powders were mixed and theproportion was optimized,which results in a synergistic effect of the components.Moreover,due to the compoun-ding effect and the grinding effect of different components,reasonable particle size distribution and better dense packing efect were obtained,resulting in a g0od combination of all the different components,thus improving the performance of the mineral admixture and reducing the cost.Experimental results show that,when the content of the fly ash-based admixture is 50% (mass fraction)in cement,the 7-day and 28-day activity indexes respectively achieve 56.26% and 76.6%.and that the water consumption for the standard consistence of the muhi-component cementitious powder decreases,while the slump and strength of concrete increase.

Key words: fly ash, mineral admixture, synergistic efect, grinding effect, dense packing effect