Faculty Publications
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Item Acid, alkali and chloride resistance of binary, ternary and quaternary blended cementitious mortar integrated with nano-silica particles(Elsevier Ltd, 2021) Snehal, K.; Das, B.B.This paper investigates the quantification of ettringite (Ca6Al2(SO4)3(OH)12.26H2O, AFt), gypsum (CaSO4.2H2O, Gy) and Friedel's salt (Ca4Al2(OH)12Cl2.4H2O, Fs) formed for binary, ternary and quaternary blended cementitious mortar mixes that were exposed to acid (H2SO4), alkali (Na2SO4) and chloride (NaCl) solutions. Quantification was carried out through a thermogravimetric analyzer by characterizing the mass loss associated to the decomposition of these compounds at specific boundaries of temperature (50–120 °C for AFt, 120–150 °C for Gy and 230–380 °C for Fs). Binary, ternary and quaternary blended cementitious mortar mixes were designed by adopting modified Andreasen and Andersen particle packing model. A long-term exposure period was spanned to the duration of 180 days for all kind of aggressive media and its effect on engineering properties of blended cementitious mortar were measured. Deterioration due to acid (H2SO4) exposure is found to be more intense due to the synergistic action of acid and sulfates. It is to be noted that for acid exposure period of 180 days, control mortar underwent an acute density and strength losses of 18% and 59%, respectively. However, cementitious mortar mix consisting of 3% nano-silica performs the best against aggressive media. The optimistic resistance to the formation of AFt and Gy was also found to be offered by quaternary blended mix. A similar trend was also observed in the formation of Fs for the mortar mixes exposed to NaCl solution. Significant improvement in particle packing density by the inclusion of micron to nano sized finer particles for quaternary blended mortar mix has minimized the permeable porosity, thus reduced the susceptibility to the formation of voluminous compounds. Enhanced pozzolanic activity due to the presence of nano-silica could be one of the primary reasons for quaternary blended mortar to perform better against the aggressive media that can be adopted in the practice considering sustainability and economical point of view. © 2021 Elsevier LtdItem Pelletisation factors on the production of fly-ash aggregates and its performance in concrete(ICE Publishing, 2023) Shivaprasad, K.N.; Das, B.B.; Sharath, B.P.This research study investigates the factors associated with pelletisation in the production of fly-ash aggregates and its performance in concrete. To investigate this influence, experiments were carried out in different stages to explore the effect of factors responsible for pelletisation, which were designed through Taguchi’s experimental design. Additionally, the influence of each parameter on the engineering properties of the produced aggregates was determined using Grey relational analysis. Further, considering the optimised pelletisation factors of the laboratory-scale studies and with the help of an industrial-scale pelletiser, mass production of fly-ash aggregates was carried out and characterised for their engineering properties. The test results indicate that these aggregates are mainly governed by water content followed by the angle and speed of pelletizing disc. It is observed from the results that the engineering properties of aggregates produced on an industrial scale are found to be better than sintered aggregates and also comparable with that of natural aggregates except for water absorption. The properties of concrete produced with fly-ash aggregates, light weight sintered aggregates and natural aggregates were also studied. The results showed that properties of concrete produced with fly-ash aggregates are in good correlation with those of conventional concrete produced with natural aggregates. © 2023 ICE Publishing. All rights reserved.Item Potential utilization of regional cashew nutshell ash wastes as a cementitious replacement on the performance and environmental impact of eco-friendly mortar(Elsevier Ltd, 2023) Manjunath, B.; Ouellet-Plamondon, C.M.; Das, B.B.; Bhojaraju, C.Globally, agro-waste ashes are increasing significantly due to the rapid implementation of biomass-based power plants. In the present trend, agro-wastes are disposed of in an unsustainable manner. The recycling of agro-waste has significantly contributed to sustainable goals. In the construction sector, it is possible to dispose of waste more efficiently. However, the efficiency of locally available agro-residual waste in cementitious composites is not well understood. In the present investigation, the practicability of using agro-residual ash obtained from the burning of cashew nutshells on the properties of eco-friendly blended cement paste and mortars is explored. Blended cement mixtures containing cashew nutshell ash (CNSA) were prepared at five replacement levels, 5, 10, 15, 20, and 25%, relative to the weight of the cement. To understand the characteristics of CNSA, microstructure investigations such as X-ray diffraction, thermogravimetric analysis (TGA), scanning electron microscopy, and energy-dispersive spectroscopy analyses were performed. Paste properties of CNSA-based cement are observed through consistency, setting time, mini-slump flow, and expansion tests. For the CNSA-based mortars flow table, compressive strength, ultrasonic pulse velocity (UPV), electrical resistivity (ER), water absorption, bulk density, and porosity tests were performed to understand its efficiency. The strength indices of mortars were used to quantify the pozzolanic effect of CNSA. With the incorporation of CNSA, water demand increased by 57%, initial and final setting time decreased by 90% and 83%, respectively. Results showed that CNSA-based mortars absorbed more water and had higher porosity, which reduced compressive strength, UPV, and ER values. CNSA blended mortar is more suitable for applications that do not require high compressive strength. Results indicated that the compressive strength, UPV, and ER are within the limit specified. Strength indices indicated that CNSA has a positive and negative pozzolanic effect during early and later ages, respectively. Further, the sustainable assessment showed that the introduction of CNSA in mortar could substantially reduce embodied carbon, embodied energy, and strength efficiency over the control mortar. The inadequate amount of SiO2, Fe2O3, and Al2O3 in CNSA makes it an unsuitable pozzolanic material. However, it can be utilized in smaller amounts as a fractional replacement of cement and is found to be promising for specific desired properties of cement as a cost-effective accelerator. © 2023 Elsevier LtdItem Influence of Geopolymerization Factors on Sustainable Production of Pelletized Fly Ash-Based Aggregates Admixed with Bentonite, Lime, and GGBS(American Society of Civil Engineers (ASCE), 2023) Sharath, B.P.; Snehal, K.; Das, B.B.; Barbhuiya, S.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. © 2023 American Society of Civil Engineers.Item Life Cycle Assessment of construction materials: Methodologies, applications and future directions for sustainable decision-making(Elsevier Ltd, 2023) Barbhuiya, S.; Das, B.B.This review paper presents a comprehensive analysis of Life Cycle Assessment (LCA) methodologies applied to construction materials. It begins with an introduction highlighting the significance of LCA in the construction industry, followed by an overview of LCA principles, phases and key parameters specific to construction materials. The methodological approaches utilised in LCA, including inventory analysis, impact assessment, normalisation, allocation methods and uncertainty analysis, are discussed in detail. The paper then provides a thorough review of LCA studies on various construction materials, such as cement, concrete, steel and wood, examining their life cycle stages and environmental considerations. The review also explores recent advances in LCA for construction materials, including circular economy principles, renewable alternatives, technological innovations and policy implications. The challenges and future directions in LCA implementation for construction materials are discussed, emphasising the need for data quality, standardisation, social aspects integration and industry-research collaboration. The provides valuable insights for researchers, policymakers and industry professionals to enhance sustainability in the construction sector through informed decision-making based on LCA. © 2023 The AuthorsItem Effect of Iron Ore and Copper Ore Tailings on Engineering Properties and Hydration Products of Sustainable Cement Mortar(ASTM International, 2024) Sumukh, E.P.; Das, B.B.; Barbhuiya, S.The prohibition of river sand mining has drawn the attention of researchers in finding practicable alternatives. In the approach of finding these alternatives, it is essential to ensure minimal or zero impairment to the ecological balance, which can be mainly attained by making use of industrial waste/byproducts. The wastes from the mining industry are the major contributors in causing impairment to the environment, and their influence on the stability of mortars on using as fine aggregates needs to be systematically investigated with the view of long-term performance concerns. Thus, the present study explores the applicability of mine tailings and finding the optimum dosage in cement mortars by investigating the engineering properties and microstructure development with the aid of qualitative and quantitative analysis associated with hydration products. The studies confirm that the increased consumption of portlandite for secondary hydration reactions followed by the additional formation of calcium silicate hydrate (CSH) and calcium aluminum silicate hydrate (CASH) phases in mine tailing-based mortars helped in achieving a quality microstructure. These additional formations of CSH and CASH phases are also confirmed through Fourier transform infrared spectroscopy by identifying the shift of Si-O-Si stretching vibration bands toward a lower wavenumber. The lowering of calcium/silicate atomic ratio and increased formation of mineralogical compounds related to CSH and CASH in x-ray diffraction patterns also confirms the same. Gismondine, chabazite, and hillebrandite are the additional phases formed and found to take part in refining the pore structure. This enhanced performance of mine tailing mortars was also verified with the aid of a modified Andreasen and Andersen particle packing model. The formation of high-quality microstructure is reflected in the hardened properties of optimized cement mortar in the proportion of 20 % for iron ore tailing and 30 % for copper ore tailing. © © 2024 by ASTM International.Item Advances and perspectives in engineered cementitious composites: a comprehensive review(ICE Publishing, 2024) Barbhuiya, S.; Adak, D.; Das, B.B.Engineered cementitious composites (ECCs) have garnered significant attention within the construction industry, owing to their exceptional mechanical properties and durability. This thorough review presents a meticulous analysis of the progress and prospects in ECC research. It begins by introducing the background and rationale for investigating ECCs, while outlining the objectives of the review. The review provides an encompassing overview of ECCs, encompassing their definition, characteristics, historical development, composition and constituent materials. Emphasis is placed on the examination of ECCs' mechanical properties, specifically their flexural behaviour, tensile behaviour, compressive strength and resistance to environmental factors. Furthermore, the rheological properties of ECCs, including workability, flowability, self-healing, crack mitigation, viscosity and thixotropy, are discussed in detail. The review delves into the influence of fibre reinforcement on ECCs, encompassing the types of fibres utilised and their impact on mechanical and structural properties, as well as fibre dispersion and orientation. Additionally, it explores the diverse applications of ECCs across various fields, such as structural applications and sustainable building practices. The challenges and limitations associated with ECCs, such as cost and availability, are addressed, alongside an exploration of future trends and research directions. © 2024 ICE Publishing. All rights reserved.Item Biochar-concrete: A comprehensive review of properties, production and sustainability(Elsevier Ltd, 2024) Barbhuiya, S.; Das, B.B.; Kanavaris, F.The utilisation of biochar in concrete has attracted considerable attention due to its potential in enhancing the properties and sustainability of this construction material. This in-depth review delves into various aspects of biochar-concrete composites. It commences by defining biochar and exploring its production methods, physical and chemical properties. Additionally, the review provides an overview of concrete, emphasising its composition, properties and the challenges associated with traditional production methods. The incorporation of biochar in concrete brings forth several benefits, such as improved strength and durability, enhanced thermal properties and the potential for carbon sequestration. The paper examines the production process of biochar-concrete composites, covering aspects like incorporation methods, biochar selection, mixing techniques and quality control measures. Furthermore, the sustainability aspects of biochar-concrete are evaluated, considering its environmental impact, life cycle assessment, carbon footprint reduction and economic feasibility. The review also addresses the challenges and future perspectives of biochar-concrete composites, along with opportunities for research and development. This comprehensive review presents valuable insights into the properties, production and sustainability of biochar-concrete composites. It serves as a guide for further advancements in the realm of sustainable construction. © 2024 The AuthorsItem Enhancing sustainability with ternary blended cement and fine aggregate in self-compacting lateritic concrete with supplementary materials(Elsevier Ltd, 2025) Kiran Bhat, K.; C, R.; Das, B.B.This study explores an innovative approach to sustainable self-compacting concrete (SCC) by partially replacing natural fine aggregate (NFA) with lateritic fine aggregate (LFA) and manufactured sand (M-sand). Additionally, fly ash and ultrafine ground granulated blast furnace slag (UGGBS) were introduced as supplementary cementitious materials to enhance performance. Fresh properties of the SCC mixes met as per Indian standards, demonstrating satisfactory flowability, passing ability, and stability. Among the mixes, the combination of 30 % fly ash (30 F), 30 % LFA (30 L) and 50 % M-sand (50 M) replaced in the conventional SCC mix, designated as C30F30L50M, exhibited optimal workability and segregation resistance. Mechanical tests revealed improvements in long-term strength, with the optimized mix containing 5 % UGGBS showing superior flexural strength at 90 days. Durability assessments indicated increased water absorption in mixes containing LFA and M-sand, while the control mix displayed better resistance to chloride penetration. Microstructural analyses (SEM, XRD, TGA/DTG, and FTIR) confirmed enhanced hydration and phase development influenced by the blend of fine aggregates and supplementary materials. The findings highlight the potential of utilizing LFA and M-sand in SCC to achieve sustainable concrete with improved performance characteristics. © 2025 The Authors