Construction and Building Materials 323 (2022) 126488 Available online 25 January 2022 0950-0618/© 2022 Elsevier Ltd. All rights reserved. Feasibility for co-utilisation of Carbonated Reactive Magnesia Cement (CRMC) and industrial wastes in circular economy and CO 2 mineralisation Erick Grünh¨ auser Soares a, * , Jo˜ ao Castro-Gomes a , Mateusz Sitarz b , Tomasz Zdeb b , Izabela Hager b , Khaled Hassan c , Mohammed Saif Al-Kuwari d a Centre of Materials and Building Technologies (C–MADE), Department of Civil Engineering and Architecture, University of Beira Interior (UBI), 6201-001 Covilh˜ a, Portugal b Cracow University of Technology, Faculty of Civil Engineering, Chair of Building Materials Engineering, Warszawska 24, 31-155 Cracow, Poland c Infrastructure Research & Development (IRD), Qatar Science and Technology Park – Education City, Al Luqta St, Ar-Rayyan, Doha, P.O.Box 210021, Qatar d Environmental and Municipal Studies Institute, Ministry of Municipality and Environment, Doha 2713, Qatar A R T I C L E INFO Keywords: Carbonated reactive magnesia cement CO 2 adsorption Circular economy Waste-based materials Mortars ABSTRACT The increased concern about climate change is leading to the growth of research interest in alternatives to mitigate its effect. Such trend is also observed in the materials and building technologies feld, where among the many possible alternatives. Cementitious composites with a lower CO 2 footprint have been recently developed to incorporate waste in their composition, with the capability to adsorb CO 2 . This study evaluates the feasibility of incorporating seven different wastes sources as fller and/or magnesia replacement in Carbonated Reactive Magnesia Cement (CRMC)-based mortars. CRMC-based mortars were designed to incorporate reactive magnesia and waste powders, by the volume ratio of three to one (sand to paste). The mortar specimens were cast by static compaction pressure and cured through accelerated carbonation curing for 24 h at controlled conditions. The performance of CRMC-based mortars was evaluated by compressive strength and microstructural examination. TG-DTG and FT-IR analysis were used to investigate the carbonation effectiveness through the specimens’ vol- ume. The results showed that the designed mortars embodying waste have achieved strength values of 8.5 to 14.6 MPa and the carbonation took place at the whole volume independently of the waste-based material used. The compressive strength results were found to be infuenced by the pH of the raw materials. The study demonstrated that CRMC-based mortars have good binding properties with the different wastes investigated with the capability of adsorbing CO 2 the surrounding environment into the cementitious matrix. It provides inno- vative solutions for the circular economy in the construction sector aside to sequestrate carbon within the built environment. 1. Introduction The production of Portland cement (PC) based concrete represents about 7% of anthropogenic carbon dioxide (CO 2 ) emissions worldwide, being the most consumed manufactured material in the world [1]. However, the concerns about climate change [2] and CO 2 emissions [3] provided an increase of the interest in more environmentally friendly materials that may reduce the use of PC [4,5] which follow some carbon emissions mitigation levers suggested as (i) use emerging and innovative technologies that can integrate carbon capture into the cement manufacturing process for long-term storage, and (ii) reduce the clinker in cement proportion [1]. Among the alternatives to PC-based materials are the Alkali- activated, Belite-ye’elimite, and Carbonatable binders [5] being the later one reported as the only technology that could signifcantly reduce CO 2 emissions related to the construction industry sector on a long-term period [6]. Thereby leading to a recent rise of interest in binders based on this technology, such as the Carbonated Reactive Magnesia Cements (CRMC). Such class is based on the natural mineral carbonation process of Magnesia (MgO), which adsorbs CO 2 to form stable carbonates [7]. The carbonation process of CRMC-based materials is usually described as the preliminary hydration of the reactive MgO (r-MgO) * Corresponding author. E-mail addresses: e.grunhauser@ubi.pt, jpcg@ubi.pt (E. Grünh¨ auser Soares), mateusz.sitarz@pk.edu.pl (M. Sitarz), tzdeb@pk.edu.pl (T. Zdeb), izabela.hager@pk. edu.pl (I. Hager), khassan@irdme.net (K. Hassan), msakuwari@mme.gov.qa (M. Saif Al-Kuwari). Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat https://doi.org/10.1016/j.conbuildmat.2022.126488 Received 24 September 2021; Received in revised form 20 December 2021; Accepted 14 January 2022