Effect of Liquid-to-Solid (L/S) Ratio on The Characteristics of Metakaolinbased Geopolymer Mortar for Lightweight Panel Applications

Geopolymer Mortar Metakaolin Liquid-To-Solid Ratio Compressive Strength Density Water Absorption One-Way ANOVA

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September 14, 2026

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The development of low-carbon construction materials has become increasingly important to mitigate the environmental impacts associated with the extensive use of Portland cement. Metakaolin-based geopolymer mortar has emerged as a promising alternative binder due to its environmental advantages and favorable engineering properties. This study aimed to determine the optimum liquid-to-solid (L/S) ratio and evaluate its effects on the compressive strength, density, and water absorption of metakaolin-based geopolymer mortar. An experimental laboratory investigation was conducted using five liquid-to-solid (L/S) ratios of 0.40, 0.45, 0.50, 0.55, and 0.60. The evaluated properties included compressive strength, density, and water absorption. Statistical significance was assessed using a one-way analysis of variance (ANOVA).The L/S ratio significantly influenced all measured properties. The optimum performance was achieved at an L/S ratio of 0.45, which resulted in the highest compressive strength (16.60 MPa), the highest density (1.96 g/cm³), and the lowest water absorption (4%). One-way ANOVA confirmed that the L/S ratio had a significant effect on compressive strength, density, and water absorption (p < 0.001). The liquid-to-solid ratio was identified as a critical parameter governing microstructural densification, porosity development, and the physical and mechanical properties of metakaolin-based geopolymer mortar. An L/S ratio of 0.45 was recommended as the optimum condition for achieving balanced mechanical performance and durability-related properties.