Performance of Fiber-Reinforced Ultra-High-Performance Concrete Incorporated with Microencapsulated Phase Change Materials

In the era of environmental concerns, many attempts were proposed to optimize energy efficiency for buildings and consequently reduce their carbon footprint. As a sustainable approach, it is a promising solution to incorporate phase change materials (PCMs) in construction materials (i.e., ultra-high-performance concrete (UHPC)) to increase its thermal storage capacity and reduce the operation energy. However, incorporating microencapsulated phase change materials (MPCMs) into cementitious materials negatively impacts the fresh and hardened properties. UHPC’s improved mechanical strength allows for the creation of slimmer and lighter structures, which may result in less demand in concrete manufacturing and fewer emissions. Hence, the properties of UHPC incorporated with MPCMs (MPCM-UHPC) need more investigations. To fill the gap in the literature about the lack of information about MPCM-UHPC performance, this paper provides a comprehensive work to study the mechanical, thermal, and impact resistance properties of (MPCM-UHPC). Proportions of 5% and 10% of MPCMs were incorporated as a replacement of sand by volume. Proportions of 0.5%, 1.0%, and 1.5% of micro steel fiber reinforcement were used as a percentage of the mixture’s total volume. The results revealed the importance of fiber reinforcement in compensating for the negative effect of MPCMs inclusion for improving the thermal properties. Increasing the amount of MPCMs enhanced the thermal performance of the produced UHPC panels through the ability to absorb and release the energy during the phase change process.