Evaluation of durability characteristics and life cycle behaviour of high-performance concrete

This paper examines the effect of metakaolin (MK) on the long-term durability properties and life cycle behaviour of high-performance concrete (HPC) at lower and higher w/b ratios. The binder in the study was replaced with MK from 0 to 30% at 5% intervals by weight to produce HPC at 0.3w/b and 0.45w/b. The concrete mix was examined for its workability, compressive strength and durability properties such as shrinkage, acid resistance, water penetration, surface resistivity and chloride penetration. The workability of HPC lowers with an increase in the substitution of MK owing to its finer particle fractions. The optimal replacement of MK was found to be 10% showing enhancement in the concrete properties. The durability properties of HPC also tend to enhance at optimized percentages of MK. Furthermore, an increase in the w/b ratio affects the concrete properties and concrete mixes under prolonged curing exhibit enhanced concrete properties. The microstructure of the HPC mixes examined through XRD and SEM show refinement in the concrete microstructure with the addition of MK and thus show improved concrete properties. Life cycle analysis was performed for the HPC mixes at 0.3w/b and 0.45w/b with different percentages of MK.