Investigations of Waste Marble Powder in Improving Strength and Water Absorption Characteristics of fly ash Geopolymer Composites
摘要
This study investigates the performance of Waste Marble Powder (WMP) as a partial replacement of fly ash to produce brick-sized geopolymer composites. The geopolymer composites were prepared with varying sodium hydroxide (NaOH) molarities (4 M, 6 M, 10 M, and 12 M), WMP contents (0%, 10%, 20%, 30%, and 40% by weight), curing temperatures (room temperature, 60 °C, 80 °C, and 120 °C), and curing periods. Based on the experimental investigations, the compressive strength was found to be improved by increasing WMP contents. The highest compressive strength of geopolymer was found to be 37.13 MPa, corresponding to 40% WMP, at a concentration of 12 M. The compressive strength increases with an increase in curing temperature from ambient conditions to 120 °C, and with an increase in NaOH concentration from 4 M to 12 M. Three-way factorial ANOVA analysis also confirms that the alkaline activator molarity, WMP content and curing temperature significantly affects the compressive strength of geopolymer composites. However, the alkaline activator molarity (M) is more influential parameter in governing the compressive strength of geopolymer mixes compared to WMP content and curing temperature (CT). Microstructural analysis further indicates that enhanced geopolymerization process (at higher NaOH concentration, higher WMP content, and elevated curing temperature) leads to the formation of dense structural matrix due the filler effects along with the possible formation of Ca- and Na-based aluminosilicates, which are responsible for the improvement in strength and water absorption characteristics of geopolymer composites.