Contribution Rate Of The Strength Of Fly Ash In Cement - Fly Ash Cementitious System

The micro-aggregate effect, active effect and morphological effect of fly ash and the application of them in cement and concrete, which have formed the basic frame of application of fly ash in cement based materials, have always been one of the hot research topics for the materials scientists both home and abroad.For the micro-aggregate effect of fly ash, at the same water-binder ratio, certain kind of inert material with the same fineness as the fly ash can be added in and mixed with it. The strength contribution to the cement-fly ash cementitious system can be acquired by comparing the compressive strength of pure cement paste in which the inert powder material is added and that in which the inert powder material is not added. This thesis tries to make quantitative analysis of the micro-aggregate effect of fly ash in special given conditions to verify the already existing theoretic analysis.For active effect of fly ash, the thesis chooses a certain kind of inert material with the same fineness of the fly ash. By comparing the intensity of the inert material with the same admixture amount and fly ash cementitious system, the strength contribution to the cement-fly ash cementitious system by the active effect of fly ash can be acquired.For the morphological effect of fly ash, under the same liquidity, this thesis compares the intensity of pure cement paste and the cement-fly ash cementitious system with different admixture amount, obtaining the principle of strength contribution to cement-fly ash system by the morphological effect of fly ash.It should be pointed out that the effects of fly ash are not isolated from each other; instead, they are related to each other complicatedly. The combined action of these effects on the performance of cement is not a simple superposition of these effects but changes regularly.