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Shuqing Yang (1), Hongzhi Cui (2), Chi Sun Poon (1)
Cement and Concrete Composites, 114, August 2020. DOI: 10.1016/j.cemconcomp.2020.103720
Glass concrete, Dry-mix method, High temperatures, Compressive strength
This paper presents an investigation on high temperature performance of dry-mix and wet-mix concretes using 0–100% glass aggregates to replace river sand. The thermal conductivity at room temperature and the compressive strength before and after exposure to elevated temperatures were evaluated. The dry-mix and wet-mix concretes with the content of 100% glass aggregates were examined by X-ray μCT, microhardness and SEM-BSE to explain the noticeable property improvement after exposure to 800 °C. Regardless of the casting method, the increasing content of glass aggregates reduced the thermal conductivity at room temperature and improved the compressive strength after exposure to 800 °C. This was because the surface of the glass aggregates was partially melted at 800 °C and it re-solidified after cooling, which served to enhance the bond between the glass aggregates and the cement paste. The new bonding played a role in filling up the gap between the glass aggregates and the cement paste and partially repaired the decomposition of cementitious materials after exposure to 800 °C. With a constant content of glass aggregates, the dry-mix concrete had a lower thermal conductivity at room temperature and a higher residual compressive strength after exposure to 800 °C than the wet-mix concrete. This was due to the higher initial porosity of the dry-mix concrete and the glass aggregates which were not completely attached to the cement paste, both of which would contribute to reliving the thermally induced expansion.
Dragonfly was used to perform the pore segmentation for determining the porosity and to perform the quantitative analysis of pore structure.
(1) Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
(2) Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, College of Civil Engineering, Shenzhen University, Shenzhen, China.
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