CRUSHED ANDESITE POWDER AS A CEMENT FILLER MATERIAL - EFFECT ON STRENGTH AND DURABILITY PROPERTIES

Crushed andesite powder was used as an inert filler material to partly replace plain Portland cement (PC). The powder had a volume-weighted mean particle size of 23.2 µm, and a particle distribution curve characterised with D10, D50 and D90 values of, respectively, 1.8, 13.7 and 55.1. The powder replaces 15% and 30% by mass of PC, and the blend used to make test specimens at two waters to cement+filler (w/c+f) ratios of 0.40 and 0.60. The concretes were assessed for compressive strength (3, 7, 28 and 90 day), hydration kinetics (isothermal calorimetry) and penetrability with respect to chloride, gaseous and moisture ingress. Results show that strength varies with w/(c+f) ratio and PC replacement level. Penetrability of concrete decreases with increasing filler content and increasing w/(c+f) ratio. The results suggest that the crushed andesite powder can potentially be used as a filler material in PC, with careful considerations given to strength and durability requirements.