Development and thermal response of concrete incorporated with multi-stage phase change materials-aggregates for application in seasonally frozen regions. (15th July 2023) - Ying, Honghao
Abstract: Frost heave damage occurs frequently in cold regions, which has a serious impact on building engineering. Concrete incorporated with phase change materials (PCMs) is promising in alleviating frost heave by release latent heat. This study aims to develop concrete integrated 100% multi-stage PCMs-aggregates as coarse aggregates and study the thermal response of multi-stage PCMs-concrete. Firstly, the pore properties of shale ceramsite were characterized by mercury intrusion porosimetry (MIP) analysis techniques. Then three PCMs (dodecane, tridecane and tetradecane) impregnated into shale ceramsite respectively to prepare PCMs-aggregates. The effect of different impregnation method and the influence of pore properties on impregnation were evaluated. In order to avoid leakage and improve interface performance, modified epoxy resin and cement powder were used as double-layer coating materials and its optimum addition level was obtained from comparative experiments. Freeze-thaw test showed the effectiveness of coated PCMs-aggregate for leakage resistance. Subsequently, 100% PCMs-aggregate replaced coarse aggregate in volume to prepare single-stage PCMs-concrete and multi-stage PCMs-concrete. The thermal response indicated that the multi-stage PCMs-concrete limits extreme temperature (5.2 °C) compared with reference concrete. The compressive strength test indicated that PCMs-concrete strength was acceptable. Taken overall, multi-stage PCMs concrete exhibited excellent thermal regulation ability at multiple temperature points in a range of 5 °C to −15 °C, which possessed important practical significance to alleviate frost heave damage in cold regions. Highlights: Shale ceramsite is a suitable container for PCMs impregnation. Coating materials can prevent PCMs-aggregate leakage effectively. Multi-stage PCMs-concrete shows potential application in cold regions. Multi-stage PCMs-concrete enables multi-stage temperature regulation.