Self-compacting concrete with low cement consumption and incorporation of rice husk and metakaolin

ABSTRACT

The concrete production process generates a significant environmental impact because it is one of the largest consumers of raw materials such as sand, stone and water. However, the greatest impact is caused by the production of Portland cement, a material indispensable to concrete. The reduction of cement consumption to produce cement materials is an important ally for the sustainability of buildings. Thus, this study evaluates the rheological, physical, mechanical and chloride ion diffusion properties in self-compacting concrete (CAA) with the incorporation of high levels of rice husk pozzolan (PCA) and metakaolin (MK) in tertiary mixtures. For this purpose, two compositions of self-adensible concrete were analyzed with substitution of 40% and 50% of cement by tertiary mixtures with 20% of PCA and 20% of metakaolin and 30% of PCA and 20% of metakaolin, respectively, and a reference CAA with a consumption of 450 kg/m³ of science was also analyzed. CAA characterization tests were performed in fresh state (slump flow test with T500, J ring, V funnel and L box), besides water absorption, void index, specific mass, compression resistance and chloride migration in non-stationary regime in CAA after 28 days of cure. The results showed that the synergy of the pozzolanic mixtures provided mechanical performances and durability superior to the reference CAA, producing self-adensible concrete with low cement consumption of high resistance and durability against chlorides.

Keywords
Self-compacting concrete; Sustainability; Pozzolan of rice husk; Metakaolin; Low levels of cement