Enhancement of engineering properties of cement mortars with masonry construction and demolition fines via carbon dioxide utilization, storage and chemical treatment

Dwivedi, A and Bollam, R and Gupta, S (2024) Enhancement of engineering properties of cement mortars with masonry construction and demolition fines via carbon dioxide utilization, storage and chemical treatment. In: Construction and Building Materials, 439 .

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Abstract

Shortage of natural sand is severely affecting the global construction industry. The construction sector also generates a substantial amount of construction and demolition (C&D) waste of which masonry wastes constitute a major fraction. Using a circular economy approach, this article explores the feasibility of using treated masonry waste fines (MWF) to replace 75 of natural sand in Portland cement-based mortars. The treatment consists of a combination of acid washing and CO2 curing to improve the engineering properties of MWF-cement mortars. 0.1 mol/L and 0.5 mol/L (M) H2SO4 were used for chemical treatment of the MWF followed by CO2 curing at 50,000 ppm for 4 hours. Mortars containing treated MWF (MWF-0.1 M-C and MWF-0.5 M-C) were subject to conventional curing (moist curing followed by dry curing at 30 �C and 65 RH) and carbon sequestration via accelerated carbonation curing. Experimental findings suggest that combined treatment with acid and CO2 reduces the pore volume by 13 � 27 in the pore size range of 10 � 100 nm in MWF. Consequently, mortars with MWF-0.1 M-C and MWF-0.5 M-C show 29 � 30.50 higher compressive strength at 28-d age and a 29 � 36 reduction in total shrinkage compared to mortars with similar dosages of as-received MWF. This ensures statistically similar strength and shrinkage as that of the plain mortar (with 100 natural sand), demonstrating the potential for 75 sand replacement using treated MWF. Furthermore, carbon sequestration of 16.40 � 19 by mass of Portland cement is achieved, which contributes to a 15 enhancement in early strength and reduces the mesoporous volume and shrinkage by up to 43 and 15�19 respectively. In summary, the research offers a pathway to recover a �new sand� from C&D wastes, which could be used to manufacture masonry construction products with reduced demand for natural sand. © 2024 Elsevier Ltd

Item Type:	Journal Article
Publication:	Construction and Building Materials
Publisher:	Elsevier Ltd
Additional Information:	The copyright for this article belongs to Elsevier Ltd.
Keywords:	Carbon dioxide; Compressive strength; Concretes; Construction industry; Curing; Demolition; Mortar; Pore size; Portland cement; Sand, Carbon dioxide utilization; Carbon sequestration; Cement mortars; Chemical treatments; Construction and demolition; Construction and demolition waste; Construction sectors; Engineering properties; Masonry waste; Natural sand, Shrinkage
Department/Centre:	Division of Mechanical Sciences > Centre for Sustainable Technologies (formerly ASTRA)
Date Deposited:	17 Dec 2024 11:30
Last Modified:	17 Dec 2024 11:30
URI:	http://eprints.iisc.ac.in/id/eprint/85811

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