Experimental investigation on effects of calcined bentonite on fresh, strength and durability properties of sustainable self-compacting concrete

With the current focus on sustainable development in the civil engineering field, it is necessary to develop construction and building materials with reasonable costs and low environmental impacts in order to reduce CO₂ emissions during the production of concrete, and from the cement industry as a whole. This research studies the effect of using calcined bentonite (CB) as partial replacement of Ordinary Portland Cement (OPC) on the sustainability of self-compacting concrete (SCC). The cement in SCC mixes has been replaced with two different types of CB at 0, 5, 10, 15, 20, 25 and 30% by weight. Slump flow, V-funnel flow time, L-box test and sieve stability tests are performed to evaluate the fresh properties of SCC mixtures. Various tests are used to assess the performance of SCC mixtures in hardened states, such as compressive strength, porosity accessible to water, chloride-ions penetration and gas permeability. The results showed that the use of CB in SCC mixes reduced the fresh properties of SCC and the slump flows, flow times, and segregation tests are good enough for SCC production. At a hardened state, SCC with 10–15% of CB had a higher compressive strength up to 90 days, as well as improved porosity, chloride-ions penetration and gas permeability properties. These results indicate that a CB solution will reduce CO₂ emissions and make durable and eco-friendly SCC at a low cost.