Investigation of the Effects of Using Activated Carbon Instead of Pumice Aggregate on the Physical and Mechanical Properties of Geopolymer Foam Concrete Composites

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This study investigates the effects of partially replacing pumice aggregate with activated carbon in geopolymer foam concrete (GFC) production on its physical and mechanical properties. Within the scope of the study, activated carbon was used as a replacement for pumice at varying ratios of 5%, 10%, 15%, and 20%, and its impact on fresh mortar rheology, mechanical strength, water absorption capacity, porosity, and high-temperature resistance was evaluated. The results indicate that as the activated carbon content increased, the flow diameter of the fresh mortar decreased by 25.6%, from 168 mm to 125 mm, while the fresh unit weight decreased by 8.6%, from 1535 kg/m³ to 1402 kg/m³. The 28-day compressive strength values ranged between 2.205 MPa and 1.205 MPa, showing a reduction with increasing activated carbon content. However, the percentage increase in compressive strength from 7 to 28 days rose from 15% to 38% as the activated carbon content increased. High-temperature tests conducted at 200°C revealed a reduction in compressive strength across all mixtures, with AC0 exhibiting a strength loss of 5%, while AC20 reached a loss of 20%. Additionally, porosity increased by 53%, water absorption capacity by 65%, and capillary water permeability by 38%. SEM images demonstrated that the presence of activated carbon led to an increase in microcrack formation within the binding phase and resulted in increased porosity in the matrix. These findings suggest that while substituting activated carbon adversely affects mechanical strength, it may offer advantages in engineering applications requiring low density and high water absorption capacity.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.