Accelerated carbonation of ternary cements containing waste materials

• Published in: Construction & building materials 2021-10, Vol.302, p.124159, Article 124159
• Main Authors: Rita Damasceno Costa, Ana, Pereira Gonçalves, Jardel
• Format: Article
• Language: English
• Subjects: Ceramic brick waste; Ceramic tile waste; Marble waste; Phosphogypsum; Supercritical carbonation; Ternary cements
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2021.124159

•Waste of clay brick, clay tile, marble and phosphogypsum are viable to produce TC.•The sustainability of TC can be improved by the use of waste materials.•TC is less durable than PC under carbonation by ScCO2 on the applied conditions.•The calcined clay/limestone ratio affected the TC susceptibility to carbonation. Limestone calcined clay cement has great potential for reducing the environmental footprint associated with cement production. Few studies have explored ternary cement (TC) carbonation or the production of TC-containing waste materials. This study investigates TC carbonation using supercritical carbon dioxide (ScCO2) as an alternative method to accelerate the process. TCs were produced from waste raw materials, including wastes of clay brick (WCB), clay tiles (WCT), marble (WM), and phosphogypsum (PG). The formation of phases before and after ScCO2 attack were analysed using TG/DTG/DTA, XRD-Rietveld, and FTIR. The axial compressive strength, Rockwell surface hardness, and the advance of the carbonation depth were determined for different TC pastes. The results show that the aforementioned wastes can be used as alternatives to natural sources of supplementary cementitious materials (SCMs) to produce TC. Using WCB to replace calcined clay in TC resulted in the highest quantity of carboaluminates among the investigated pastes, in addition to high axial compressive strength and resistance to attack by ScCO2. The properties of the TCs were similar to those reported for limestone calcined clay cement in the literature, presenting less durability than Portland cement (PC) under carbonation by ScCO2 in the applied conditions. The calcined clay/limestone ratio influenced the behaviour of the pastes through changes in the C–H content. Increasing this ratio increased the extent of carbonation of WCT pastes and decreased the extent of carbonation of WCB pastes. The sustainability of TC can be improved via the use of waste materials.