Development of lightweight high-alumina cement mortars integrated with n-octadecane/expanded vermiculite for improving building energy efficiency


ÖZTÜRK S., KÜÇÜKDOĞAN ÖZTÜRK N., Gencel O., SÜTÇÜ M., Ustaoglu A., SARI A., ...Daha Fazla

Construction and Building Materials, cilt.506, 2026 (SCI-Expanded, Scopus) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 506
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1016/j.conbuildmat.2025.144919
  • Dergi Adı: Construction and Building Materials
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC
  • Anahtar Kelimeler: Energy and Energy Efficiency, Expanded vermiculite, Heat storage, High alumina cement, PCM
  • Karadeniz Teknik Üniversitesi Adresli: Evet

Özet

Phase change materials (PCMs) offer strong potential for reducing building energy demand. This study aims to develop lightweight structural mortars with improved indoor thermo-regulation by incorporating a form-stable PCM (FSPCM). The FSPCM was produced by impregnating expanded vermiculite (EV) with n-octadecane at a 40 wt% ratio. The reference mortar was prepared using EV as a lightweight aggregate at 25 wt% relative to cement. To obtain thermally enhanced composites, this EV fraction was replaced with FSPCM at substitution levels of 25–100 %. All mixtures were characterized to evaluate their physical, mechanical, and thermal performance. The mixture completely replaced with FSPCM showed the most significant improvements, achieving a thermal conductivity of 0.456 W/mK, density of 1.07 g/cm³ , and compressive strength of 8.81 MPa. DSC analysis of the FSPCM revealed melting and solidification temperatures of 25.76 and 25.42 °C, with latent heats of 100.4 and 99.5 J/g. Thermo-regulation tests confirmed effective reduction in indoor temperature fluctuations. A preliminary cost–performance evaluation, based on unit material prices and experimentally observed thermal benefits, indicates that FSPCM-integrated mortars may provide favorable life-cycle economics despite higher initial material costs. In conclusion, the EV/n-OC composites demonstrate strong potential as sustainable and energy-efficient building materials.