Post-cyclic Static Behavior of Carbon Short-fiber-reinforced Concrete (CSFRC) Under Tension

Abstract

Ultra-high-performance concrete (UHPC) is of interest to many researchers today. This concrete is produced by adding fibers to the fresh concrete matrix during mixing, where the matrix is a fine-grained mix with a maximum particle size of 1 mm. Various types of fibers can be added to the concrete matrix: steel, natural, polypropylene, polyvinyl alcohol, etc. fibers. Short carbon fibers are also used.
Reinforcing concrete with short carbon fibers results in carbon short-fiber-reinforced concrete (CSFRC). CSFRC has approximately twice the tensile strength of high-strength concrete (HSC) and about 400% higher tensile strength than normal-strength concrete. In addition to high tensile strength, CSFRC is also characterized by ductile behavior under tension and flexion. Although this concrete has been the subject of much research, its behavior has not been sufficiently studied yet to be fully explained. Thus, there are no available results on its post-cyclic static behavior in the literature. Therefore, an aim of this work is to provoke further research in this area. To this end, experimental results obtained from two specimens are presented here. In both tests, tensile prior cyclic loading preceded tensile static loading, and the behavior of CSFRC under these loadings is observed. The number of cycles of harmonic loading preceding the static loading varied: one specimen underwent 6 million cycles, and the other 10 million. The results show a difference; the specimen with lower number of cycles failed in an elasto-plastic manner, while the specimen with higher number of cycles failed in a brittle manner.