Synergistic effects of elevated temperatures on material characterization of quaternary-blended lightweight engineered geopolymer composites

Nejib Ghazouani , Mohd Ahmed , Zeeshan Ahmad

Abstract

This study investigates the mechanical and microstructural behavior of lightweight engineered geopolymer composites (LWEGCs) containing nano tubes under high temperatures. LWEGCs were fabricated using fly ash, silica fume, slag, metakaolin, and fly ash microspheres as binders, with ceramsite-based lightweight aggregates (LAs) such as clay-based (CBC), granulated blast furnace slag-based (GBC), and shale-based (SBC) aggregates. Compressive stress and mass loss were assessed after exposure to temperatures extending from 200oC to 800oC. Scanning electron microscopy (SEM), X-ray Diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to assess the phase assemblage of the produced LWEGC mixes. Results depicted that matrix compaction increased the compressive stress of LEGC-REF by 27.27% at 200oC, while thermal deterioration caused a considerable decrease of 43.47% at 600oC and 135.71% at 800oC. With mass loss increasing to 22.54% at 800oC, LEGC-CBC exhibited the lowest thermal stability, whereas LEGC-SBC had superior stability with 20.1% mass loss. The material's integrity was diminished by the development of cracks and a honeycomb structure at high temperatures, according to SEM research. By strengthening the geopolymer matrix and bridging microcracks, MWCNTs enhanced microstructural cohesiveness despite degradation. This study emphasizes how LWEGCs can be used in high-temperature applications and how LAs and MWCNTs can enhance mechanical and fire resistance.

Key Words

compressive stress; elevated temperatures; lightweight engineered geopolymer composites; scanning electron microscopy

Address

Nejib Ghazouani — Mining Research Center, Northern Border University, Arar, 73213, Saudi Arabia
Mohd Ahmed — Department of Civil Engineering, College of Engineering, King Khalid University, PO Box 394, Abha 61411, Saudi Arabia; Center for Engineering and Technology Innovations, King Khalid University, Abha 61421, Saudi Arabia
Zeeshan Ahmad — Department of Civil Engineering, University of Engineering and Technology Taxila, 47050, Pakistan

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