Sustainable concrete incorporating fly ash and metakaolin: Experimental insights and machine learning analysis

The study aims to investigate the impact of fly ash and metakaolin on strength and durability of the concrete containing Prosopis juliflora (50 ppm). Fourteen different mix combinations involving different proportions of fly ash and metakaolin ranging from 0% to 15% were designed. Tests were conducted to assess workability, mechanical properties, water absorption, and chloride ion permeability at various curing periods until 90 days. From the results obtained, increase in metakaolin proportion decreases workability but increases the strength and durability of concrete. The best mix design, which was M11 (containing 10% fly ash and 10% metakaolin) recorded maximum strength values of 53.32 MPa, 4.67 MPa, and 5.22 MPa in compressive, tensile, and flexural strengths at 28 days respectively. M11 also recorded minimum values of water absorption (2.37%) and chloride permeability (2007 coulombs). Microstructure analysis revealed that the microstructure is fine for the M11 mix.