Faculty Publications

Now showing 1 - 3 of 3

Influence of multi-stage processing and mechano-chemical treatments on the hydration and microstructure properties of recycled aggregate concrete
(Elsevier Ltd, 2023) Trivedi, S.S.; Sarangi, D.; Das, B.B.; Barbhuiya, S.
On account of the shortage of naturally occurring coarse aggregate, recycled aggregate (RA) made from crushed concrete debris is now used in the construction industry. With this rise in the utilisation of recycled aggregate in the construction sector, there has been extensive research into ways to improve its quality. The significant fraction of mortar remains that are left on the RA surface is the primary factor that affects its quality. Concrete made from RA loses strength and mechanical performance due to the attached mortar's increased porosity and water absorption values and the frailer transition region between the new mortar and aggregates. In order to minimise the old cement fractions and increase the quality, this paper studies the effect of concrete incorporating multi-stage processed RA from demolished concrete waste, followed by treatment with mechanical abrasion and sodium silicate immersion. The recycled aggregates were produced through multi-stage jaw crushing, followed by utilising natural aggregate, recycled aggregate, and recycled aggregate obtained after mechanical abrasion, followed by sodium silicate treatment for concrete mix design at various substitution percentages as coarse aggregates. The experimental investigation further progresses with the evaluation of mechanical and durability properties of concrete mixes, which is additionally followed by microstructural studies such as scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDAX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Thermogravimetry-differential thermal analysis (TG-DTA). The outcomes demonstrate that two-stage treatment, such as mechanical abrasion followed by sodium silicate immersion, yields superior-quality RA. Recycled aggregate concrete (RAC) made with these treated aggregates illustrated an increase in workability and density with respect to an untreated RAC mix. Furthermore, comparable strengths in compression, flexure, and tension are found in treated RAC mixes, particularly at 35% replacement levels, with respect to concrete mixes comprised of natural aggregates. A similar trend is detected in the chloride penetration tests and water sorptivity tests. In addition, the microstructural investigation confirmed the formation of additional calcium silicate hydrate for treated RAC mixes, particularly for the 35% substituted RA mix. On the basis of the results, it is suggested that multi-stage jaw crushing followed by treatment through mechanical abrasion and sodium silicate can potentially enhance the mechanical, microstructural, and durability performance of RAC. © 2023 Elsevier Ltd
Performance of construction and demolition waste as recycled aggregates in concrete - Review
(ICE Publishing, 2024) Trivedi, S.S.; Das, B.B.; Barbhuiya, S.
This article presents a structured and comprehensive review of the existing literature on physical, chemical, microstructure, and durability properties of recycled aggregate concrete (RAC). The engineering properties of concrete made from such recycled aggregates are critically analysed by focusing mainly on the fresh and hardened states along with several characterisation techniques such as scanning electron microscopy, energy dispersive X-ray, X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetry/differential thermal analysis. Also, creep, shrinkage, microstructure and durability of RAC were evaluated critically. In addition, improvement techniques in its microstructure are also explored with efficient mixing approaches for the development of geopolymer RAC. Furthermore, techniques to enhance the mechanical characteristics and long-term performance of recycled aggregate are distilled and divided into three categories: (1) lowering the porosity of recycled aggregate, (2) lowering the layer of old mortar on the surface of recycled aggregate, and (3) enhancing the property without changing the recycled aggregate. It is evident from the thorough examination that recycled aggregates can be used in concrete up to a certain amount. For the creation of sustainable and high-performance concrete, it is also necessary to incorporate mineral admixtures of micron, sub-micron, and nano size to address the drawbacks of recycled aggregates. © 2025 Emerald Publishing Limited: All rights reserved.
A comprehensive review of radiation shielding concrete: Properties, design, evaluation, and applications
(John Wiley and Sons Inc, 2025) Barbhuiya, S.; Das, B.B.; Norman, P.; Qureshi, T.
This review paper provides a comprehensive analysis of radiation shielding concrete, covering its properties, design, evaluation, and applications. It begins with an introduction, stating the objective and scope. The paper explores radiation shielding basics, including ionizing radiation, shielding principles, and materials used for shielding. Concrete's properties relevant to shielding, radiation attenuation mechanisms, and factors affecting its efficiency are discussed. Different types of radiation shielding concrete are examined, along with their applications. The design and formulation of shielding concrete, including mix proportions, optimization techniques, and quality control, are presented. Evaluation methods and standards are discussed. Lastly, challenges, future directions, and emerging technologies are outlined. This review paper serves as a valuable resource for professionals involved in radiation shielding. The review on radiation shielding concrete highlighted its effectiveness in attenuating ionizing radiation, emphasizing material composition, density, and thickness as key design factors. Evaluation methods, such as gamma spectroscopy and Monte Carlo simulations, are discussed, demonstrating its versatile applications in nuclear facilities, healthcare, and space exploration. © 2024 The Author(s). Structural Concrete published by John Wiley & Sons Ltd on behalf of International Federation for Structural Concrete.

Faculty Publications

Browse

Filters

Settings

Sort By

Results per page

Search Results