Effect of superplasticizer in geopolymer and alkali-activated cement mortar/concrete: A review

The cement and construction industry creates around 10% of the global carbon footprint. Geopolymer and alkali-activated concrete provide a sustainable solution to conventional concrete. Due to its disadvantages, the practical usage of geopolymer and alkali-activated concrete is limited. Workability is one of the issues faced in developing geopolymer and alkali-activated concretes. Plenty of research was conducted to provide a solution to enhance the ability to use different superplasticizers (SPs). The present article extensively reviews the effects of SPs on geopolymer and alkali-activated concretes. The research articles published in the last 5 years in high-quality journals are considered for the chemical composition of the different SPs and analyses of their exact impact on geopolymer and alkali-activated cement mortar and concrete. Later, the impact of SPs on the normal consistency and setting times of cement mortar, workability, compressive strength, flexural strength, split tensile strength, microstructure, and water absorption of geopolymer and alkali-activated concrete was determined. SPs improve the geopolymer and alkali-activated concretes upon their use in desired dosages; more dosage leads to negative effects. Therefore, selecting the optimal superplasticizer is essential since it impacts the performance of the geopolymer and alkali-activated concrete.