Fracture behavior of high strength concretes containing silica fume and metakaolin

The study presented in this thesis reports the findings of an experimental study conducted on fracture behavior of high strength concretes incorporating metakaolin (MK) and silica fume (SF). The concrete mixtures with water-to-binder (w/b) ratio of 0.28 and 570 kg/m3 binder content were designed for the experimental study. MK or SF modification was achieved through replacing Portland cement (PC) with mineral admixture by 5% and 15% of the total binder content. Moreover, a plain concrete mixture was produced as control for comparison. The effectiveness of MK and SF incorporation on the compressive strength, splitting and flexural strengths, modulus of elasticity, fracture energy, and characteristic length of concrete were monitored at the end of 28 days of water curing. The results have revealed that the utilization of mineral admixtures provided improvement in fracture properties such as increased fracture energy. Moreover, the results obtained for SF concretes demonstrated a similar trend to the ones incorporating MK. Increasing the replacement level from 5% to 15% resulted in relatively better performance for the concretes including mineral admixture.