Experimental investigation of the feasibility of stabilizing inshore silty sand soil using geopolymer based on ceramic waste powder: An approach to upcycling waste material for sustainable construction

Abstract

The experimental study of geopolymeric stabilized samples based on ceramic waste powder (CWP) and sodium hydroxide solution acting as an alkali activator was investigated in the present research to evaluate the possibility of geopolymeric stabilization of silty sand soil as a sustainable method for improving the mechanical properties of inshore sand soils. X-ray fluorescence spectroscopy (XRF) was employed to analyze and determine the chemical components of the CWP and natural soil. The effect of four factors on the unconfined compression strength (UCS) and failure strain (Ɛf) of silty sand soil, including CWP content (0–24%), NaOH solution concentration (0–15 M), the curing time (7, 28, and 91 days), and the initial curing temperature (25°C and 70°C), were investigated. The results demonstrated a substantial increase in both UCS and Ɛf for geopolymeric stabilized samples in comparison to natural soil and the soil that was stabilized with 5% ordinary Portland cement (OPC). The UCS and Ɛf values of the 28-day-cured optimal sample (CWP = 15% and NaOH solution concentration = 6 M) in comparison with natural soil increased from 0.080 to 2.22 MPa and from 2.31% to 5.45%, respectively. Moreover, the UCS value in this sample was 1.75, 1.81, and 1.29 times higher than the stabilized soil with 5% OPC for each curing time. Without an alkali activator, CWP addition to the soil had no effect on UCS at all curing times. However, when a 2 M NaOH solution was added to the soil without CWP, the UCS of this sample rose to 0.36 MPa after 7 days of curing. The UCS of geopolymeric stabilized samples experienced growth from 1.27 to 2.04 times by shifting the initial curing temperature from 25°C to 70°C. Through the use of energy-dispersive X-ray (EDX) spectra and scanning electron microscope (SEM) photomicrograph, the microstructure of stabilized samples was inspected. SEM photomicrographs corroborated the UCS test findings, and EDX analysis confirmed the high quality of the aluminosilicate gels' growth and production. To sum up, soil stabilization using CWP geopolymer is a cost-effective, environmentally friendly method that reduces the consumption of natural resources and energy.