Volume 44: Energy Transitions toward Carbon Neutrality: Part VII

Eco-Building Materials: Metakaolin-based Geopolymer for CO2 Emission Reduction and Enhanced Energy Efficiency Yifan Zhou, Junwei Liu, Jinyue Yan

Abstract

Considering diminishing limestone resources and escalating carbon emission regulations, geopolymers are considered to be the third generation of cementitious materials after lime and ordinary Portland cement (OPC). Geopolymers are distinguished by their strong corrosion resistance, freeze-thaw resilience, mechanical strength, and reduced CO2 emissions, positioning them as environmentally friendly alternatives to traditional cement. Metakaolin (MK) based geopolymers typically have a light-colored appearance which contributes to high solar reflectance, thereby reducing heat absorption from sunlight and rendering them beneficial for radiative cooling. Enriched with alumina (Al₂O₃) and silicon dioxide (SiO₂), MK geopolymers possess unique radiative properties, outperforming in radiative cooling experiments with a notable temperature drop of about 6.5˚C. Compared to other green alternatives like slag and fly ash geopolymers, MK geopolymers demonstrate enhanced strength and thermal stability. A life cycle assessment reveals that metakaolin-based geopolymers can mitigate carbon emissions compared to ordinary Portland cement (OPC), underscoring their role as a sustainable solution in the construction industry.

Keywords Eco-building materials, Geopolymers, Radiative cooling, Energy saving, Mechanical properties