Crushing Strength Characteristics of Artificial Fly Ash Sand in Comparison with Conventional Granular Materials

Abstract

Sand is an essential material used in various construction activities across the globe, due to which there is a scarcity of natural river sand (NRS). Consequently, it is crucial to identify new sustainable alternative granular materials that have identical strength characteristics as natural river sand for civil engineering applications. In this connection, investigations were carried out on the crushing strength characteristics of synthesized artificial fly ash sand (AFAS) with alkaline binders of 8M, 10M, and 12M NaOH, molarity for comparison with NRS, Ennore sand (ES), and glass beads (GBs). The strength characteristics of granular materials are influenced by the shape and size of the grain, strain rate, and particle aspect ratios. The granular materials thus chosen were tested for crushing strength using a strain-controlled digital loading frame to assess their suitability as a substitute for natural sand. The variations in crushing strength of the granular materials are characterized by their physicochemical, mineralogical, thermal, and engineering properties. Further, the materials were investigated through microlevel analysis by using x-ray diffraction, scanning electron microscopy, thermogravimetric analysis, differential thermal analysis (, and BET analyses. The experimental investigations show that AFAS achieved crushing strengths of 8.1 MPa (8M AFAS), 8.38 MPa (10M AFAS), and 8.17 MPa (12M AFAS). In comparison, conventional materials exhibited crushing strengths of 8.88 MPa (NRS), 6.85 MPa (ES), and 7.34 MPa (GB). So, it is apparent that the particle aspect ratio has an impact on the crushing strength of granular materials. This study would be quite useful in predicting the crushing strength of granular materials, indicating that AFAS could replace natural river sand in civil engineering applications. This study emphasizes developing sustainable granular materials by creating artificial fly ash sand (AFAS), utilizing fly ash—an industrial byproduct—combined with alkaline binders. The aim is to assess the suitability of AFAS as a fine aggregate by evaluating its crushing strength and conducting comprehensive investigations, including physical, chemical, mineralogical, and microlevel analyses relative to conventional granular materials. The findings show that AFAS performs comparably to natural river sand, making it a cost-effective and eco-friendly alternative. By utilizing industrial waste, AFAS alleviates the environmental impact of excessive sand extraction while serving various civil engineering applications, including embankments, subgrade layers, pipe backfill, partition walls, roof insulation, retaining wall filters, and lightweight concrete blocks. This innovation effectively addresses the global sand shortage and fosters sustainable construction practices, offering a practical solution to the depletion of natural river sand resources while contributing to a more environmentally responsible approach in the construction industry.