Influence of Microbial Activity on Mechanical Properties & Durability of Self-Healing Concrete using Indigenous Rhisopue Oryzae and Trichoderma Longibrachiatum

Abstract

For past few years, there has been unceasing upsurge of research to cope with the cracks in extensively used construction material known as concrete. Self-healing of concrete using microbes has shown sustainability and lower environmental impacts. The key aspiration of the study was to examine the compatibility of fungi as self-healing agent and its effects on the mechanical properties of concrete. Two strains Rhizopus oryzae & Trichoderma longibrachiatum isolated from locally available microflora were obtained. These above-mentioned strains were inoculated in the concrete matrix with and without immobilization in calcium alginate beads which is super absorbent polymer. Field emission electron microscopy confirmed that Rhizopus oryzae was able to grow on the concrete as well as able to promote calcite precipitation on the cracks of the concrete. X-Ray diffraction and thermogravimetric analysis revealed the presence of crystalline calcite precipitates confirming the microbially induced calcite precipitation. Despite using super absorbent polymers, the compressive & tensile strength of concrete did not decrease instead it slightly increased. These results show that fungus has potential to be used as suitable Self-Healing agent of concrete in future. Results showed that fungal strain Rhizopus sp. immobilized in calcium alginate beads was more effective in samples pre cracked at 3 and 7 days while bacteria immobilized in light weight aggregates were more efficient in samples pre cracked on 14 and 28 days. In addition, results of compressive strength depict that self-healing concrete made with