Aging behavior of high-performance fiber-reinforced concrete

Synopsis: Due to their enhanced properties, high strength concrete has been widely used for structural applications during the last decades. In the years, several mixes of high strength concrete reinforced with different fibers were engineered mainly to build precast elements for civil works all over the world. Specifically, high performance fiber reinforced concrete (HPFRC) is used to build bridges or shells for tunnels. Since HPFRC is a relatively young material, only few information is available in literature regarding its long-term behavior. The paper focuses on the study of the mechanical behavior of three types of HPFRC after almost fifteen years of aging. The mixes were cast in 2003 using combinations of polypropylene and steel fibers. The presented investigation aims to replicate the same experimental approach used in 2003 introducing as only additional variable the aging time. Compression tests and three points bending tests are accounted. Evolution of cracking in bending tests during the loading process was monitored using electronic speckle pattern interferometry. Experimental results from the two campaigns are compared and, the evolution of mechanical and fracture properties of the investigated mixes are discussed.