Enhancing impact resistance and thermal stability of alkali-activated concrete with nanomaterial integration: a sustainable approach for construction

Purpose This study aims to explore the potential of alkali-activated concrete (AAC) as a sustainable alternative to ordinary Portland cement (OPC), addressing the critical need to reduce carbon dioxide (CO2) emissions associated with cement production. By incorporating nanomaterials (NMs), such as nano-fly ash (nFA), nano-ground granulated blast furnace slag (nGS) and nano-bentonite (nBT), the research highlights the enhanced mechanical properties, durability and sustainability of nano-engineered AAC. Design/methodology/approach This study examines the influence of various NMs, including nFA, nGS and nBT, on the impact resistance of alkali-activated nano concrete (AANC) when subjected to elevated temperatures ranging from 200 °C to 800 °C. The results reveal notable changes in impact energy, weight loss, crack patterns, spalling behavior and capillary water absorption. Microstructural changes were examined using scanning electron microscopy (SEM), and predictive models for impact energy and residual impact energy were developed and validated. Findings The addition of NMs significantly influenced the workability, compressive strength (CS) and rebound number of alkali-activated nano concrete. The compressive strength ranged from 37.25 to 60.37 MPa at 28 days, with enhanced cracking resistance and failure impact numbers observed in NM-incorporated specimens. At 800 °C, specimens demonstrated increased energy dissipation and altered capillary water absorption rates, particularly in nBT-added samples. SEM analysis revealed microstructural modifications, including the formation of microcracks and phase decomposition. Predictive models for impact energy and residual impact energy showed a strong correlation with experimental data, with R2 values between 0.91 and 0.95. Originality/value This study underscores the potential of NM-enhanced AANC to improve impact resistance and thermal stability, offering a promising solution for sustainable construction. The findings contribute to reducing the environmental footprint of concrete production while maintaining high-performance standards, emphasizing the role of nanotechnology in advancing green construction practices.