Effects of ground coal bottom ash on the properties of cement-based materials under various curing temperatures

Abstract

Steam curing is usually used in the production of precast concrete for modern industrial buildings. To promote the recycling of industrial waste and further reduce the amount of cement used in prefabricated construction materials, this study aims to investigate the effects of coal bottom ash (CBA) on the performance of cement-based materials under various curing temperatures. The microstructures and mineral phases of hydrated cement pastes were analyzed. The hydration reactivity of CBA was improved via grinding and elevating the curing temperature. Results showed that under the curing condition of 20 °C, the compressive strength of cement mortar added with 30 wt% of CBA-40 (the ash after 40min's grinding) was increased by 12.59% compared with the one made with 30 wt% of CBA-10 (the ash after 10 min's grinding). With the same addition of 30 wt% CBA-40, the compressive strength of cement mortar cured under 192 °C was increased by 12.66% compared with that cured under 20 °C. In general, finer CBA particles and higher curing temperature exhibited positive effects on improving the properties of cement materials. This study provides a novel approach to utilize the CBA to prepare high quality mineral admixtures for being used as a replacement of cement. It was concluded that the combination of suitable steam curing regime and proper fineness of CBA could produce low cost steam-cured concrete with excellent performance which possesses significant environmental benefits.