Some engineering properties of self compacting lightweight mortars

In this study, lightweight fly ash fine aggregates (LWFAs) were used as a partial replacement of natural fine aggregate to investigate the fresh and hardened states of self compacting mortars (SCMs). For this, a powder mixture of 90% fly ash (FA) and 10% Portland cement (PC) by weight were pelletized in a tilted pan through a cold-bonded agglomeration process. Thereafter, a total of five mixtures of SCMs were prepared in which natural fine aggregate was replaced by LWFA partially started from 0% to 100% by 25% increment. Subsequently, tests carried out on the fresh mortar involved mini-slump flow, mini-V-funnel flow time, and viscosity while the hardened properties of SCMs were evaluated using the compressive strength, ultrasonic pulse velocity, gas permeability, and sorptivity tests. The hardened characteristics of SCMs were determined at different ages up to 56 days. It was observed that the increased percentage of LWFA improved the workability and the flowability of SCMs. On the other hand, some of the engineering properties of SCMs in terms of strength and permeability had a negative effect due to the substitution of LWFAs for natural fine aggregate, especially at higher replacement level.