Greener horizons: Revolutionizing construction materials with waste-based innovations - An experimental study

This is the authors' abstract. We don't add key points for this paper.

Greenhouse gas (GHG) emissions are the primary cause of the growing worry over global warming. The manufacturing of cement is a significant source of carbon dioxide emissions into the environment, which is driving up demand for sustainable building practices. Historically, there has been a lack of fully waste-based green cement, with most cementitious materials incorporating only a partial proportion of waste materials. However, recent advancements have led to the development of a supplementary cementitious material (SCM) that is entirely derived from waste byproducts. While numerous geopolymers and alkaline-activated cements (AAC) have been explored in previous research, these typically rely on commercial activators to activate the binder. In contrast, the innovative binder under investigation in this study is activated exclusively using alkaline compounds derived from waste categories, presenting a unique and sustainable approach to cement production. This advancement marks a significant step towards the creation of an entirely waste-based, eco-friendly cement solution. After 56 days, the waste-based green cement binder had a compressive strength of 22 MPa. This WGC is ideal for general construction applications. Subsequently, the developed Waste-Based Green Cement (WGC) was tested by incorporating varying proportions of Ordinary Portland Cement (OPC) to evaluate the optimal replacement level of OPC with WGC. This investigation aimed to determine the most effective substitution ratio, ensuring that the resulting composite material maintained the required performance characteristics while maximizing the use of waste-derived components. There is a possibility of a 50 % cut-off of ordinary Portland cement (OPC) with WGC, resulting 42 MPa after 28 days of ambient curing condition (maintained temperature 21 ± 2 °C and maintained relative humidity 50 ± 10 %). Mineralogical and microstructural variations influence on the mechanical performance of this WGC-OPC composites and here in this paper, it highlights. Furthermore, for the waste-based green cement mix, the optimized initial molar ratios of SiO 2 /Al 2 O 3 , Na 2 O/Al 2 O 3 , and H 2 O/Na 2 O were obtained as 3, 1, and 9, respectively. WGC has a unique ability to be reused after demolition because recast samples demonstrated a significant compressive strength of 6 MPa after 28 days of ambient curing. To address the long-term demands of ultra-high strength applications, this research aims to investigate the development of a novel sustainable Waste-Based Green Cement (WGC) while simultaneously enhancing its properties. • A 50 % replacement of OPC with WGC achieved a compressive strength of 22 MPa after 56 days, confirming its suitability for construction. • Mine tailings and rice husk ash effectively replaced conventional activators in WGC alkaline activation, offering a sustainable alternative. • WGC exhibited reusability post-demolition, with recast samples reaching 6 MPa compressive strength after 28 days, unlike OPC without admixtures. • OPC addition modified crystallization, with elongated calcite crystals observed in 50 % WGC samples, correlating with improved performance.