The Mechanical Properties of Kaolin-Based Geopolymer Concrete with Portland Cement Addition. - Wallah, Steenie E.; Rerungan, Gabriel B.; Muchaimin, Joshua I. R.; Waraba, Hendrico J.; Kakunsi, Timothy C. D.; Sumajouw, Dody M. J.; Dapas, Servie O. (Engineering, Technology & Applied Science Research, 2025)