Development of microencapsulated PCM concrete with improved strength and long-term thermal performance using MWCNTs

This study proposes the development of concrete that can maintain its strength and long-term thermal performance when microencapsulated phase change material (M-PCM) is applied. The concrete is designed for the purpose of winter heating cost reduction, prevention of building freezing, and mitigation of black ice on highways. The selection of the capsule wall for M-PCM was based on differential scanning calorimetry (DSC) measurements to assess the long-term performance of the concrete through capsule lifespan evaluation. Additionally, material experiments were conducted to evaluate the dispersion and determine the optimal amount of multiwalled carbon nano tubes (MWCNT) for enhancing the strength and thermal conductivity of the concrete. Based on the material experiments, concrete mixtures were designed, and different M-PCM contents were mixed at ratios of 3 %, 6 %, and 15 % relative to the binder to assess whether there were differences in the strength and core temperature of the concrete. Furthermore, a case was created where M-PCM was mixed after the completion of the conventional concrete casting to prevent damage. A comparison was made with a case where the conventional concrete casting method was followed, and the performance of the concrete was assessed. scanning electron microscopy (SEM) measurements were employed to compare the state of M-PCM within the concrete. As a result, when MWCNTs were added to concrete containing M-PCM, the compressive strength increased by 18.67 % and the flexural strength increased by up to 42.6 %. Additionally, the long-term thermal performance was significantly enhanced.