Research on the replacement of natural sand in concrete has garnered significant attention both nationally and internationally, driven by concerns regarding environmental sustainability, dwindling natural resources, and the quest for novel construction materials. Studies have extensively explored a range of alternative materials, including quarry dust, manufactured sand (M-sand), recycled aggregates, industrial by-products (such as fly ash and slag), and waste materials (like glass powder and plastic waste), assessing their mechanical properties, durability, and environmental impacts. Performance evaluations have been thorough, covering compressive strength, tensile strength, flexural strength, workability, shrinkage, and durability aspects such as resistance to abrasion, sulfate attack, and chloride penetration. Researchers have dedicated efforts to optimizing the mix design, utilizing experimental trials and statistical analyses to achieve desired performance characteristics while minimizing material usage and environmental impact. Moreover, there's a growing emphasis on assessing the long-term durability and sustainability of concrete mixes with alternative fine aggregates, including considerations of carbon footprint, energy consumption, water usage, and life cycle assessment. Field applications and case studies have provided valuable insights into real-world performance and challenges faced during implementation, contributing to a deeper understanding of the practical implications of using alternative fine aggregates in concrete construction. Additionally, researchers have examined regulatory and policy implications, ensuring alignment with building codes, standards, specifications, and environmental regulations governing construction material usage. This comprehensive research effort spans various disciplines, including materials science, civil engineering, environmental engineering, and sustainable development, driving forward the adoption of sustainable construction practices globally.
Significant study by Smith et al. (2018) [4] explored the use of quarry dust as a partial replacement for natural sand in concrete. The researchers conducted a series of experiments to evaluate the mechanical properties and durability of concrete mixes containing varying percentages of quarry dust. Their findings indicated that the inclusion of quarry dust improved the compressive strength and durability of concrete, with optimal replacement levels identified.
Similarly, Jones and Brown (2019) [3] conducted a comprehensive review of literature on the utilization of waste plastic as a replacement for natural sand in concrete. Their review highlighted several studies demonstrating the potential benefits of incorporating waste plastic, such as improved workability, reduced water absorption, and enhanced resistance to chemical attacks. However, challenges related to compatibility, segregation, and long-term performance were also identified, suggesting the need for further research in this area.
In a study by Garcia et al. (2020)[2], the researchers investigated the mechanical properties and environmental impact of concrete mixes containing both quarry dust and waste plastic as replacements for natural sand. Through a series of laboratory tests and life cycle assessments, they found that the combined use of quarry dust and waste plastic led to improvements in both mechanical performance and environmental sustainability, compared to conventional concrete mixes.
Furthermore, a meta-analysis by Patel and Sharma (2021) [1] synthesized findings from multiple research studies on the replacement of natural sand in concrete with various alternative materials. Their analysis revealed that while certain materials, such as quarry dust and waste plastic, showed promise in enhancing concrete properties, the optimal replacement levels and performance outcomes varied depending on factors such as particle size distribution, material characteristics, and mix design parameters.
Research has explored the utilization of quarry fines in diverse concrete applications, with the International Center for Aggregates Research (ICAR) acknowledging the potential of microfines (particles below 75 µm) in concrete formulations. Studies have identified that incorporating waste plastic as a modifier at an optimal content of 6% resulted in comparable strength to conventional concrete. Observations from test results indicated a notable increase in the compressive strength of concrete mixes with the addition of quarry dust and waste plastic fibers as modifiers [5, 6]. The compressive strength of concrete shows an upward trend with the replacement of natural sand up to 50% with an introduction of 2 to 6% waste plastics. However, beyond this threshold, specifically at 8% replacement, a decrease in compressive strength is observed. Nevertheless, with the progression of curing age, there is an increase in compressive strength despite the initial decrease observed at higher replacement levels. [7,8]. The compressive strength of concrete exhibits an increasing trend as natural sand is replaced with waste plastics, up to a 50% replacement level with an introduction of 2 to 6% waste plastics. However, beyond this threshold, particularly at an 8% replacement rate, there is a decrease in compressive strength. Nevertheless, despite this initial decrease at higher replacement levels, there is an observed increase in compressive strength with the progression of curing age. [9]. Hanson conducted a comprehensive study on structural concrete utilizing 12% unseparated sandstone quarry fines at the Craig-yr-Hesg site. The resulting product was marketed as standard C35 strength concrete, with a compressive strength of 35 N/mm2. However, the study revealed that the ultimate strength of the product exceeded 35 N/mm2 after 28 days of curing. Consequently, it was suggested that if the filler material were to be replaced, a significantly higher content of coarser-grained material would need to be mixed while maintaining the desired strength value (Lamb, 2005). [10]. Galetakis and Raka (2004) conducted a study to investigate the impact of different replacement proportions of sand with quarry dust (20%, 30%, and 40%) on the properties of concrete in both its fresh and hardened states. [11]. Saifuddin (2001)[12] investigated the influence of partial replacement of sand with quarry dust and cement with mineral admixtures on the compressive strength of concrete. The study suggested that artificial fine aggregate mortars with high fines exhibited higher flexural strength, improved abrasion resistance, higher unit weight, and lower permeability due to the filling of pores with micro fines. Consequently, the study concluded that concrete could be manufactured using all of the aggregate, including micro fines ranging from 7–18%, without the need for admixtures (Ahn and Fowler, 2001). [13].