Sustentabilidade e ecoeficiência na dosagem de concreto autoadensável : estudo para a redução do consumo de cimento e aditivos

Abstract

The production of concrete generates a high environmental impact due to its high demand for raw materials, exacerbated by the production of Portland cement, which leads to high CO2 emissions. Self-compacting concrete (SCC) requires high fines content in its formulation, resulting in a higher cement consumption to achieve flowability and cohesion. Therefore, reducing cement consumption in SCC production is necessary for sustainability in the construction industry. This research aimed to analyze the technical feasibility of SCC with lower cement consumption compared to locally used dosages, optimizing the use of cement and additives while aiming to improve performance, including strength, without increasing costs. Two compositions of self-compacting concrete were prepared, one with the incorporation of polypropylene fibers and another without fibers, used as a reference. It was possible to achieve a cement consumption of 380 Kg/m³ in both mixtures. Initially, the compatibility between cement and superplasticizer admixture was analyzed to find the saturation point for material economy. Afterward, tests were conducted to characterize the fresh-state concrete, including the slump (Flow Test), flow time (t500), and resistance to segregation. Properties in the hardened state, such as apparent density, compressive strength, modulus of elasticity, and split tensile strength, were also evaluated. With this, it was observed that even with a smaller amount of cement in the mixture composition, representing a reduction of 4.3%, the compressive strength increased by 17.6%, and the properties in the fresh and hardened states were satisfactory, contributing to a more sustainable and eco-efficient SCC.