Effect of silica fume on fracture analysis, durability performance and embodied carbon of fiber-reinforced self-healed concrete

Nowadays concrete industry is trying to develop sustainable and energy efficient materials. One of the techniques is to develop crack free concrete. Therefore, this study focusses on the use of different supplementary materials like silica fume as substitute of cement to characterize the self-healing capacity of fiber-reinforced concrete in order to produce crack free concrete. The employed concrete consists of cement Type-I, synthetic fibers of polyvinyl alcohol (PVA) type with 0.5 % by the total volume of the mix, and two different types of self-healing materials. Cement was replaced by silica fume (SF) up to 15 % with an increment of 2.5 %, sand passing from sieve # 16 and CA of size 12 mm was used to produce high-strength concrete. Three-point bending test and microscopic examination were used to investigate the role of fibers on the self-healing efficiency of fiberreinforced concrete specimens. Specimens were pre-cracked in the range of 50-100 mu m at 14 days of curing and then, placed in water for 14, 56-days water condition to assess the effect of self-healing. Digital high-range microscope was used to measure crack width after pre-cracking and at the end of every exposure duration. After the specified exposure duration, specimens were microscopically observed again to check the crack healing and re-loaded up to final failure. Outcomes were taken in terms of peak load increase value after healing stage (FCPL), controlling crack propagation due to healing effect termed as (IFTR), effect of cracking on fracture energy in terms of (IFER) and Embodied Carbon and Embodied Energy. It was found from test results that the healing efficiency in terms of FCPL, IFTR, and IFER was improved, due to the use of silica fume as it has lower surface area then OPC, which triggers healing rate faster by accumulation of healed produces near crack surface in early age. Furthermore, durability performance in terms of embodied carbon and embodied energy is also reduced because of full-crack healing, which shows profound healing effect.