Combined Effects of Metakaolin, Rice Husk Ash, and Polypropylene Fiber on the Engineering Properties and Microstructure of Mortar

Abstract

This paper reports an experimental study carried out to investigate the effects of using metakaolin (MK) and rice husk ash (RHA) as a partial replacement material for cement, and polypropylene (PP) as an additive, on the mechanical and water absorption properties of mortar. Cement mortar was produced using various replacement ratios of metakaolin ranging from 5 to 15%, and of rice husk ash ranging from 10 to 30%, by weight of cement. The PP fiber content considered was constant at 0.3%. Compressive strength, flexural strength, water absorption, ultrasonic pulse velocity (UPV) and scanning electron microscopy (SEM) analysis are reported in this paper. Results revealed that the combination of metakaolin, rice husk ash, and PP provided a positive influence on the mechanical properties of mortar. The samples incorporating the replacement of cement with a combination of 10% MK, 10% RHA, and 0.3% PP fiber showed better mechanical characteristics than the other mortar samples. In terms of water absorption, the addition of PP fiber reduced the permeability when compared with the mixtures with 15% MK and 10–30% RHA, and results indicated a higher absorption in comparison with the mortar containing 5–10% MK.