Sustainability evaluation, engineering properties and challenges relevant to geopolymer concrete modified with different nanomaterials: A systematic review

Geopolymer, a novel binder material, possesses the potential to replace conventional cement completely. Recent studies have investigated the incorporation of various nanomaterials (NMs) into geopolymer concrete (GPC) to enhance its properties. Nanotechnology, an emerging field of study, has garnered significant attention in recent decades due to its groundbreaking research and practical applications. This comprehensive review aims to elucidate the effects of nanomaterial inclusion on the workability, strength, durability, and physical and microstructural characteristics of GPC. The properties have been meticulously examined, reviewed, and discussed. Over 190 research and review articles were reviewed, analyzed, and presented to develop a database containing critical properties of GPC modified with different doses and types of NMs. The influence of introducing diverse kinds and doses of NMs on GPC behavior was assessed. Historical trends, current tendencies, challenges, and the benefits and limitations of NM-modified GPC were explored. According to this review, incorporating NMs is promising for developing high-strength or high-performance GPC. It significantly improves mechanical, microstructural, and durability properties by providing additional calcium-silicate-hydrate, calcium-aluminate-silicate-hydrate gel, and nano-filling effects in the GPC matrix. This advancement will enable the construction industry to realize the potential of NM-enhanced GPC successfully. The present review demonstrated that the geopolymer concrete showed enhancements in engineering properties and effectiveness when modified with different types of nanomaterials and tested under different conditions. The current study also presented some challenges and research gaps that should be addressed in future research studies.