Development of MgO concrete with enhanced hydration and carbonation mechanisms

• Published in: Cement and concrete research Vol. 103; pp. 160 - 169
• Main Authors: Dung, N.T., Unluer, C.
• Format: Journal Article
• Language: English
• Published: Elmsford Elsevier Ltd 01.01.2018; Elsevier BV
• Subjects: ABSORPTION; CALORIMETRY; Carbon; CARBONATES; Carbonation; Carbonation (C); CEMENTS; Compressive strength; Compressive strength (C); Concrete; CONCRETES; Formulations; HYDRATES; HYDRATION; Hydration (A); ISOTHERMAL PROCESSES; MAGNESIUM OXIDES; MATERIALS SCIENCE; Mechanical properties; MgO (D); MICROSTRUCTURE; Microstructure (B); Minerals; MORPHOLOGY; PRESSURE RANGE MEGA PA; SCANNING ELECTRON MICROSCOPY; Seeds; THERMAL GRAVIMETRIC ANALYSIS; WATER; Water absorption; X-RAY DIFFRACTION; Hydration (A); MgO (D); Carbonation (C); Compressive strength (C); Microstructure (B)
• ISSN: 0008-8846; 1873-3948
• DOI: 10.1016/j.cemconres.2017.10.011

This study proposed the use of hydration agent (HA) and seeds to improve the hydration and carbonation of reactive magnesium cement (RMC)-based concrete formulations. Hydration of RMC was evaluated by isothermal calorimetry. Water absorption and compressive strength results were used to assess the mechanical performance of RMC-based concrete samples. Quantification of hydrate and carbonate phases was performed via XRD and TGA. Formation and morphology of carbonates were observed via BSE and SEM. In addition to increasing the utilization of RMC in the carbonation reaction and facilitating early strength development, the use of HA formed large carbonate phases, while the addition of seeds improved sample microstructures via the development of dense carbonate networks. The improvements in morphology, microstructure and carbonate content in samples involving the simultaneous use of HA and seeds resulted in 56% lower water absorption values and 46% higher 28-day compressive strengths (70MPa) in comparison to the control sample.