EVALUATION OF ELASTIC PROPERTIES OF ULTRA HIGH PERFORMANCE CONCRETE REINFORCED WITH STEEL FIBER: MEAN-FIELD HOMOGENIZATION VERSUS FE HOMOGENIZATION
Marcelo S. Medeiros Jr.1; Evandro Parente Jr.1
1 Universidade Federal do Ceará
doi:10.20906/CPS/CILAMCE2017-0980
Resumo
Ultra-High Performance Concrete Fiber-Reinforced Concrete (UHPFRC) is emerging as a key component in the next generation infrastructure due to its capacity to fulfill higher demands on strength, durability, toughness, corrosion resistance, and energy absorption. Progress in reinforcing fibers design, cementitious matrices, and enhancements in the bonding between fiber and matrix has played a crucial role in achieving performance characteristics that are unprecedented in conventional concretes. The improved ductility and energy absorption capacity of UHPFRC is mainly attained through fiber bridging at cracked planes, therefore the fiber-matrix interactions at a microscopic level must be taken into account during its design phase. In this paper an elastic micromechanical analysis of steel-fiber reinforced concrete was carried out using analytical homogenization schemes. The results were later compared to a finite element model (FEM) that considered the actual fiber geometry with its curved ends (hooked-end fiber). The results from the FEM displayed strong agreement with the micromechanics models developed for elliptical inclusions. The results pointed out to the feasibility of using elliptical inclusions with an equivalent aspect ratio in lieu of the actual fiber geometry when calculating strain concentration tensors and their relationship to the overall composite stiffness.
Palavras-chave: UHPFRC; Micromechanics; Mean Field Homogenization