Efeito do tipo de agregado nas propriedades mecânicas em concretos de ultra alto desempenho

Abstract

High-performance concrete (HPC) and ultra-high performance concrete (UHPC) represent significant advancements in materials technology, providing custom properties, exceptional mechanical strength, and superior durability. These characteristics are closely tied to material composition, with reinforcing particles (or aggregates) being a fundamental component. This study aimed to investigate the influence of particle type, particularly hardness and granulometry, on the mechanical properties of ultra-high performance concrete. Test specimens were produced using various types of aggregates, icluding quartz poder, silicon carbide, alumina, ilmenite, magnetite, hematite and steel shot. After curing, the specimens were subjected to direct tensile and compression tests to evaluate your performance. The results demonstrated that the choice of aggregate plays na important role in the mechanical strengths of UHPC. Finer aggregates with a more uniform particle size distribution and higher hardness provided better results in terms of tensile and compressive strength. The better interaction between aggregate particles and the cement paste, observed in concretes with finer aggregates, especially qaurtz poder, contributed to increased strength. The presence of voids and heterogeneities at the paste-aggregate interface negatively impacted the mechanical performance of concrete.