The effect of fly ash aggregates on the self-healing capacity of bacterial concrete

Abstract

In concrete structures, crack development is a typical phenomenon, it reduces durability and strength. To solve this issue, an autonomous self-healing mechanism was introduced. This mechanism aids in the repair of cracks by generating the calcium carbonate crystals that seal the concrete's pores and micro-cracks. Bacillus subtilis was used in the concrete mix as an additive. In this work, the coarse aggregate was replaced partially by Fly ash aggregates in different proportions. Total eleven concrete mixes are cast and tested for strength properties, in that seven without bacteria and four with bacteria. The crack healing capacity of the concrete specimens was observed at regular intervals by using Elcometer and Digimizer software. The relation between initial crack width and percentage of crack healing was observed. The concrete mix with 30% of fly ash aggregate replacement showed high increment strength in strength of 61.37% and complete healing of maximum cracks width 0.25 mm.

Keywords

• Self-healing
• Fly ash Aggregate
• Bacillus Subtilis
• Compressive strength