Effect of limestone powder on properties of self-leveling mortar

Mixing limestone powder (LP) in the self-leveling mortar (SLM) can not only solve the problems of LP waste randomly piled up and secondary utilization of resources, but also reduce the raw material cost of SLM and have excellent mechanical properties. The effect of replacing fly ash (FA) with LP and replacing cement with LP after completely replacing FA on fluidity and strength of SLM are studied. The microstructure of SLM is measured by mercury intrusion porosimetry and scanning electron microscope. The results show that the initial fluidity and the 20-min fluidity of SLM decrease gradually with the increase of LP content. The strength of SLM increases and then decreases with the increase of LP replacing FA, and the strength is the highest when the addition of LP is 40%. When LP replaces cement after completely replacing FA, the strength of SLM decreases with the increase of displacement. Excessive LP can greatly damage the mechanical properties of SLM. The appropriate content of LP can improve the microstructure of SLM and promote the formation of hydration products, which is helpful to reduce the porosity and thus improves the structure density. This may be due to the chemical reaction and the microfiller effect of LP.