CUED Publications database

Accelerated carbonation and performance of concrete made with steel slag as binding materials and aggregates

Mo, L and Zhang, F and Deng, M and Jin, F and Al-Tabbaa, A and Wang, A (2017) Accelerated carbonation and performance of concrete made with steel slag as binding materials and aggregates. Cement and Concrete Composites, 83. pp. 138-145. ISSN 0958-9465

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Abstract

© 2017 Elsevier Ltd Steel slag has been used as supplementary cementitious materials or aggregates in concrete. However, the substitution levels of steel slag for Portland cement or natural aggregates were limited due to its low hydraulic property or latent volume instability. In this study, 60% of steel slag powders containing high free-CaO content, 20% of Portland cement and up to 20% of reactive magnesia and lime were mixed to prepare the binding blends. The binding blends were then used to cast concrete, in which up to 100% of natural aggregates (limestone and river sands) were replaced with steel slag aggregates. The concrete was exposed to carbonation curing with a concentration of 99.9% CO 2 and a pressure of 0.10 MPa for different durations (1d, 3d, and 14d). The carbonation front, carbonate products, compressive strength, microstructure, and volume stability of the concrete were investigated. Results show that the compressive strength of the steel slag concrete after CO 2 curing was significantly increased. The compressive strengths of concrete subjected to CO 2 curing for 14d were up to five-fold greater than that of the corresponding concrete under conventional moist curing for 28d. This is attributed to the formation of calcium carbonates, leading to a microstructure densification of the concrete. Replacement of limestone and sand aggregates with steel slag aggregates also increased the compressive strengths of the concrete subjected to CO 2 curing. In addition, the concrete pre-exposed to CO 2 curing produced less expansion than the concrete pre-exposed to moist curing during the subsequent accelerated curing in 60 °C water. This study provides a potential approach to prepare concrete with low-carbon emissions via the accelerated carbonation of steel slag.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div D > Geotechnical and Environmental
Depositing User: Cron Job
Date Deposited: 25 Jul 2017 03:54
Last Modified: 21 Nov 2017 03:07
DOI: