Influence of fly ash on properties of cement-based materials

This paper presents the influence of content and fineness of fly ash on the properties of cement-based materials. The fly ash having different fineness can improve the flowability of the pastes to different extent. The setting time was prolonged with the increase of fly ash content. The non-evaporable water content continuously increases with the increment of curing age. The larger the fly ash content is, the less the non-evaporable water content expressed on a unit mass of binder basis will be, but the more will be if that expressed on a unit mass of cement basis. The early strength of harden pastes before 28 days is decreased, and the decreasing degree is larger when the fly ash content is more than 40 percent, The early strength of the hardened mortars is decreased, but the later age strength can catch up with or even beyond that of the mortars without fly ash.