Resíduo de britagem em substituição da areia natural em compósitos do tipo SHCC e sua aplicação como encamisamento de concretos

Abstract

The construction industry is recognized as a sector with significant contributions to the economic and social development of a country. However, with its development, there is also an increase in the consumption of natural resources and, consequently, the generation of waste. Despite society, and particularly the construction industry, acknowledging the importance of natural resources, their exploitation in large quantities is still authorized, even amidst the global growth of environmental sustainability. Aggregates used in this industry are the most consumed mineral inputs worldwide. Therefore, this study investigated the physical and mechanical behavior of strain hardening cementitious composites (SHCC) replacing natural sand with crushed sand, aiming to evaluate its feasibility as reinforcement in concrete structures. Four different granulometries of crushed sand were analyzed, seeking optimal utilization, considering that the sand size significantly influences SHCC properties. Additionally, fly ash with two distinct fineness levels was used in the SHCC mixtures and its matrix. Results demonstrated that augmenting the granulometry of crushed sand and using beneficiated fly ash resulted in greater fracture toughness of the matrix. There was no significant increase in the compressive strength of the composite with the increase in sand grain size, with both types of fly ash. However, mixtures with crushed sand showed higher compressive strength compared to natural sand. SHCC with beneficiated fly ash had, on average, 60% higher axial compressive strength than residual fly ash. All mixtures exhibited strain hardening behavior, but as the sand grain size increased, the tensile deformation capacity decreased. The reinforcement of SHCC showed satisfactory strength results, highlighting the relevance of the proposed substitutions. These findings contribute to the development of more sustainable structural reinforcement techniques in the construction industry.