Utilization of Fly Ash and Stone Dust to Improve the Compressive Strength of Mortar

Faculty of Engineering, Lambung Mangkurat University, 70123 Banjarmasin, Indonesia

^* Corresponding author: iprasetia@ulm.ac.id

Abstract

The consumption of raw materials in the construction industry is rapidly increasing each year. Therefore, the construction industry has started turning to sustainable alternative materials, especially concrete and mortar. This research aims to assess the effect of fly ash and stone dust (as alternative materials) in mortar mixtures. For this purpose, mortar samples were prepared by substituting 100% fine aggregate (sand) with stone dust. Additionally, the cement replacement ratio with fly ash was set at 25%, 30%, and 35%. To evaluate the effect of water to binder (w/b) ratio, mortar samples were prepared with w/b ratios set at 0.3, 0.35, and 0.4. Furthermore, samples were cured for 7, 28, 42, and 90 days. The mortar samples were made according to SNI 03-6825-2002, with dimensions of 5x5x5 cm. The results show that different w/b and fly ash ratios affect mortar’s compressive strength. Mortar mixtures with a w/b ratio of 0.35 and a 35% replacement ratio of cement with fly ash are suggested as optimal due to their impressive compressive strength outcomes and environmentally friendly composition. Furthermore, it was also observed that 42 days is the most effective curing period for mortar with fly ash and stone dust.