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    Physico-mechanical properties and thermal monitoring performance of thermal enhanced cement slurry-coated LWAs containing microencapsulated phase change material
    (Elsevier, 2024) Emiroglu, Mehmet; Ozguler, Alper Tunga; Nas, Memduh; Subasi, Serkan; Sari, Ahmet; Hekimoglu, Gokhan; Ustaoglu, Abid
    Over the past decade, phase change materials (PCMs) have emerged as promising solutions for thermal energy storage (TES) systems, aimed at minimizing heating and cooling energy requirements in buildings. Nevertheless, despite their potential, there are some significant challenges in effectively integrating PCMs into building components. As part of this study, lightweight aggregates (LWA) were coated with a cement slurry containing microencapsulated phase change material (MPCM) to produce lightweight concrete (LWC) with the aim of investigating its mechanical and thermal properties. The LWAs were coated with MPCM at proportions of 2.5%, 5%, and 7.5% of their weight, and an LWC-MPCM was produced using these coated aggregates. The LWC-MPCM exhibited a decrease in dry unit weight up to 1248 kg/m 3 and a reduction in thermal conductivity up to 0.60 W/ mK with negligible loss of strength. SEM examinations revealed that the cement slurry coating provided strong adhesion to the aggregates, resulting in a robust concrete-aggregate interface. The room with the LWC-MPCM experienced a decrease of approximately 0.23 degrees C in center temperature compared to the reference room during the daytime. Additionally, after sunset, the LWC-MPCM showed an increase of approximately 1 degrees C in room center temperature. These advantageous physico-mechanical and thermal properties establish LWC-MPCMs as promising and energy-efficient components for producing thermo-regulative building materials.
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    Thermal energy storage and mechanical enhancement of cement composites containing PCM-impregnated and cement-slurry coated pumice aggregates
    (Elsevier, 2025) Gencel, Osman; Ozguler, Alper Tunga; Guler, Onur; Ustaoglu, Abid; Hekimoglu, Gokhan; Sari, Ahmet; Emiroglu, Mehmet
    In the field of thermal energy management and building materials, PCM has been impregnated into aggregates and added to cement to produce composite concretes. However, challenges such as PCM leakage and poor interfacial bonding have limited their widespread application. To address these issues, this study utilized pumice aggregates with exceptional porosity, impregnated with PCM and coated with cement slurry, to develop enhanced composite concretes. The produced composites were characterized through compressive strength tests, thermal conductivity measurements, ultrasonic pulse velocity analysis, and detailed thermal regulation experiments under dynamic solar radiation. Thermal regulation experiments were conducted using thermal imaging under real-time heating and cooling processes. Results demonstrated that PCM-impregnated aggregates enhanced the thermal stability of concrete, with surface temperatures on PCM-based composites (MAL-2) being approximately 5 degrees C lower during heating compared to control samples (MAL-K). During the cooling process, MAL-2 exhibited delayed temperature reduction, stabilizing surface temperatures around 1 degrees C higher than MAL-K due to PCM's latent heat release. Experimental outcomes further presented that an increasing proportion of PCM-impregnated aggregates significantly reduced porosity from 13.55 % to 7.87 % and improved compressive strength from 12.7 MPa to 16.81 MPa. Thermal conductivity increased from 0.5706 to 0.7058 W/mK, while water absorption decreased from 13.94 % to 7.13 %. Ultrasonic pulse velocity values increased from 2.49 km/s to 2.58 km/s, indicating enhanced matrix integrity. This design, offering superior thermal regulation and mechanical performance, holds great promise for applications in energy-efficient building materials and sustainable construction practices.