A Study on non Destructive Tests and Flexural Strengths of Geopolymer Concrete Using Combination of Different Fine AggregatesM. Indhumathi, V. Ragavan, A. Dhanalakshmi and D. Darling Helen IydiaE3S Web Conf., 387 (2023) 04001DOI: https://doi.org/10.1051/e3sconf/202338704001