Mechanical and Microstructural Properties of Clay Tile Waste Concrete Treated With Silica Fume

Abstract

The increasing generation of Ceramic Clay Tile Waste (CCTW) has prompted the construction industry to explore sustainable alternatives in concrete production. This study investigates the use of CCTW aggregates as a partial replacement for natural coarse aggregates in concrete and silica fume (SF) as a pozzolana, addressing sustainability challenges in the construction industry. While CCTW offers environmental benefits, its porous nature compromises concrete durability by increasing water absorption and weakening the interfacial transition zone (ITZ). To overcome these limitations, SF, a highly reactive pozzolanic material, was incorporated at varying dosages (0%, 5%, 10%, 15%, and 20%) to enhance the performance of CCTW concrete. Comprehensive tests were performed including compressive strength, split tensile strength, and durability analysis such as water absorption and sulfate resistance over a curing period of 28 and 90 days, respectively. The results identified 15% SF as the optimal level, beyond which a decline in performance was observed, yielding the highest compressive strength (22 MPa at 28 days). Additionally, the inclusion of SF significantly improved the microstructure of the mixtures, reducing water absorption and enhanced resistance to sulfate environments. Average density of (2355 kg/m3), and reduced water absorption (4.937%) was also observed. Microstructural analysis using SEM and EDS revealed improved particle fibrous packing, refined ITZ, and reduced porosity in the optimized mix. These findings demonstrate that SF significantly enhances the durability and structural integrity of CCTW concrete. This research substantiates the potential of utilizing CCTW and SF in concrete applications, contributing to a circular economy in the construction sector and promoting sustainable practices by reducing landfill waste while maintaining material performance standard.