Life cycle assessment and environmental impact of blended cementitious mortar with incinerated biomedical waste Ash as partial replacement to cement Pranshu Tripathi, Sarthak Joshi, K. Snehal, B.B. Das Construction and Building Materials, 2025 In a sustainability-driven world, repurposing industrial byproducts into construction materials is vital for reducing environmental impact and resource conservation. Incinerated biomedical waste ash (IBWA), typically regarded as hazardous landfill waste poses significant environmental challenges. However, high calcium (∼45 %) and silicate phases in IBWA contribute to hydration and pozzolanic reaction making it a potentially sustainable cementitious material. From this perspective, this study investigates the life cycle assessment and environmental impact of blended cementitious mortar incorporated with IBWA as a partial replacement for cement, focusing on its ecological and technical benefits. A cradle-to-gate life cycle assessment (LCA) confirmed that uutilization of IBWA in cementitious mortar conserves natural resources, reduces embodied energy consumption, lowers CO 2 emissions, and minimizes eutrophication and human toxicity potential by capturing heavy metal within hydration products. To ensure environmental safety, TCLP-ICP-MS analysis was conducted, which affirms that IBWA leachate concentrations were well below EPA regulatory limits and further reduced during hydration, stabilizing heavy metals (Cr, Cu, Hg, Ni, Pb, etc.) in the solidified matrix. The optimal IBWA dosage of 10 % offered a balance between both technical performance and sustainability. The porous and non-spherical morphology of IBWA increased water demand and inter-particle friction, and its SiO₂ + CaO content (>50 %) enhanced cement hydration. Thermogravimetric analysis (TGA), Xray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) analyses confirmed the progressive formation of secondary hydration products (C-S-H, and C-A-S-H), contributing to densified microstructure (Ca/Si ratio: ∼1.2). The final sustainable performance score of 0.77 for the IBWA10 mix signifies an eco-efficient and balanced formulation, offering structural integrity along with environmental and economic advantages.
Resistance to acid, alkali, chloride, and carbonation in ternary blended high-volume mineral admixed concrete Bibhuti B. Das, Leon Black, Salim Barbhuiya, Kusumadhar Snehal, Ekkeri Prakash Sumukh Journal of Sustainable Cement Based Materials, 2024 The World Bank study predicts that 4 °C warming will bring high temperatures, sea-level rise, and saltwater intrusion to coastal areas, damaging coastal concrete structures. Increased CO2 from industrialization exacerbates this, necessitating durable, low-carbon concrete. Combined use of fly ash (FA) and ground granulated blast furnace slag (GGBFS) as high-volume OPC replacements boosts performance while reducing concrete’s carbon footprint. In this perspective current study examines the durability of concrete against aggressive agents (H2SO4, MgSO4, NaCl, and CO2) causing premature deterioration of concrete structures. Initially, three cost-effective sustainable concrete mix designs were developed, incorporating 50% replacement of OPC with locally available supplementary cementitious materials, specifically FA and GGBFS. These mixes were then evaluated for their mechanical and durability performances. The impact of aggressive ions (SO42−, Cl−, and CO32−) was studied by examining the changes in mechanical performance and phase assemblages. Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) techniques were used to estimate the phase compositions. Ternary blended concrete having 50% OPC+ 30% GGBFS + 20% FA exhibited optimal synergistic performance, enhancing pozzolanic and hydraulic reactions for better resistance to harmful ions. The sorptivity test confirmed that as the GGBFS content increased, the sorption rate decreased, indicating the higher reactive nature of GGBFS to that of FA. Deleterious compounds formed due to the action of SO42-, Cl-, and CO32- were identified to be ettringite (Ca6Al2(SO4)3(OH)12.32H2O, AFt) and gypsum (CaSO4.2H2O, Gy), Friedel’s salt (Ca4Al2(OH)12Cl2.4H2O, Fs) and polymorphs of calcium carbonate (CaCO3), respectively through TG mass loss curve. These results were corroborated by FTIR analysis, which showed predominant characteristic bands at 662 cm−1 for SO42−, 459 cm−1 for Mg–O stretching, 790 cm−1 for Al–OH bending, and 1431-1443 cm−1 for C–O, confirming the presence of the deleterious compounds.
Influence of Geopolymerization Factors on Sustainable Production of Pelletized Fly Ash-Based Aggregates Admixed with Bentonite, Lime, and GGBS Bevinahalli Prakash Sharath, Kusumadhar Snehal, B. B. Das, Salim Barbhuiya Journal of Materials in Civil Engineering, 2023 This experimental research investigates the influence of geopolymerization factors such as Na2O dosages, water and mineral admixture [bentonite (BT), burnt lime (BL), and ground granulated blast furnace slag (GGBS)] on physiomechanical properties of the pelletized fly ash (FA)–based aggregates. Taguchi’s L9 orthogonal array was adopted to design the mixing ratios for three kinds of fly ash–based aggregates (in the combinations of FA-BT, FA-BL, and FA-GGBS). The degree of geopolymerization of the produced aggregates was characterized using thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and a scanning electron microscope (SEM). Most influential response indices in the production of pelletized aggregates were identified using gray relational analysis. The physiomechanical characteristics of the fly-ash aggregates were significantly improved by admixing BL than that of GGBS and BT. However, pelletization efficiency was seen to be superior for GGBS-substituted fly-ash aggregates. The quantified amount of hydration products, i.e., sodium alumino-silicate hydrate (N-A-S-H)/calcium alumino-silicate hydrate (C-A-S-H) for fly ash–based aggregates intensified on increasing Na2O and mineral admixture dosages. The results strongly suggest the existence of a linear relationship between the quantified amount of N-A-S-H/C-A-S-H and individual pellet strength of produced aggregate. The FTIR spectrum showed strong and broadened bands of Si-O terminal for all types of aggregates, representing the conversion of unreacted minerals to chains of aluminosilicate gel (geopolymerized hydration product). Further, it can also be inferred from gray relational analysis that among all other factors, Na2O content significantly impacted the engineering properties of produced fly ash–based aggregates.
