Effective Utilization of Foundry Waste as Aggregates in Developing Eco-Friendly Alkali-Activated and Conventional Concretes for Sustainable Pavement Infrastructure

Abstract

The current research adapts waste foundry sand (WFS) as a partial replacement to fine aggregate, which contributes to the principles of circular economy, providing economic and environmental advantages by rethinking waste as an essential resource of innovative and environmentally friendly building materials. This article mainly aims to showcase the research outcomes from the investigations carried out on the development of pavement quality slag-based conventional concretes (PQSC) and alkali-activated concrete (PQAC) using WFS as a partial substitution to conventional river sand (RS) aggregates. The mix design and the mechanical performances have been studied to comprehend the performance of WFS in concretes at various levels. Rigorous works were further carried out to fix the aggregate percentage of RS and WFS for the satisfactory mix design of the concrete mixtures. The mechanical strength parameters were studied along with volume-of-permeable-voids, density, and water absorption for durability assessments. The selected blends were sent to microstructural investigations involving scanning electron microscope (SEM), energy-dispersive X-ray analysis (EDAX), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) studies. A successful attempt was also made to develop rigid pavement design models using both the IRC method and KENPAVE software, and a comparative scrutiny was carried out. The results demonstrate that the utilization of WFS can be achieved to a maximum of 15% to 20% without significantly reducing the performance of PQSC and PQAC mixtures for road applications after ensuring satisfactory mechanical performances. The research results will pave a path for effective utilization of WFS in construction industry and provide a sustainable solution to significant waste management problems in the casting industry. This research paper focuses on the fruitful utilization of industrial waste materials in the construction industry, specifically in the context of rigid pavements. Specifically, the study highlights the potential benefits of incorporating blast furnace slag and waste foundry sand (WFS), in achieving a more sustainable and circular construction economy. It compares the mechanical performances of slag-based AAC and conformist OPC concretes for pavement applications, finding that the former is superior. The study also explores the optimal percentage replacement of WFS in place of natural fine aggregates, noting that alkali-activated mixes can accommodate a higher percentage of replacement than OPC concretes. Rigid pavements, made of developed concrete, are a durable and sustainable alternative to flexible pavements. They are suitable for various highway infrastructure applications due to their load-bearing capacity, resistance to wear and tear, and ability to handle heavy vehicles and traffic volumes. They also offer improved aesthetics, walkability, reduced lifecycle costs, and sustainability through the use of industrial waste materials. Therefore to summarize, the adaptation of WFS incorporated, slag based alkali-activated concrete offers a better mechanical performance making it suitable for rigid pavement applications which in turn help in preserving the natural aggregates contributing to sustainability.