An investigation on the performance of lightweight mortar-based geopolymer containing high-volume LECA aggregate against high temperatures

Abstract

The influence of lightweight expanded clay aggregate (LECA) on the physico-mechanical properties and microstructure of geopolymer mortar containing slag binder alkali-activated with sodium silicate solution before and after exposure to thermal loads was investigated. In the current procedure, siliceous sand was partially substituted with LECA fine aggregate at levels of 0%, 25%, 50%, 75%, and 100%, by volume. The effect of LECA on the performance before exposure was evaluated by measuring flowability, water absorption, bulk density, thermal conductivity, and compressive strength. To monitor the behavior after exposure, a batch of specimens having the same composition was subjected to high temperatures in the range of 400-1000 °C for 2 h with a heating rate of 5 °C/min. In a similar fashion, mass loss and residual compressive strength were determined. New phase-based geopolymers were examined using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The findings indicated that the incorporation of LECA up to 100% as an alternative to siliceous sand aggregate in geopolymer mortar has an adverse effect on compressive strength and water absorption, but has a positive effect on workability, thermal conductivity, and relative strength after exposure to elevated temperatures.

Titanium Dioxide Sol-Gel/Zinc Oxide Powder-Coated Clay Beads in Photocatalytic Reactor

“…The advantages of clay beads over other supporting materials are their vast availability in nature, cheapness, and environmentally friendly [41]. Furthermore, their high porosity is useful, making them great adsorbents [42,43]. Therefore, the present work aims to characterize and evaluate the photocatalytic performance of TiO2/ZnO-coated on clay beads.…”