Impact Resistance of Sustainable SFRCC Road Pavement

Abstract

The examinations of properties of steel fiber reinforced cement composite (SFRCC) specimens do not reflect properties of these composites in an actual pavement, tunnel or bridge. Each, even the most basic road pavement or structure, works within constantly changing conditions, where different loads appear and disappear in time. The impact strength of SFRCC is strongly influenced by a number of factors that tend to increase the statistical variations. Therefore the design of SFRCC elements should be based on statistical considerations of their properties. A drop weight test is the simplest test for evaluating impact resistance as the relative performance of plain cement composite and SFRCC containing different types and volume fractions of fibers. The research program was divided into three main stages. The first stage covered VeBe test, measurement of density of hardened composite and compressive strength. The main aim of the first stage of this research program was to check quality and homogeneity of the cement composites. The second stage covered multiple drop-weight load. During the drop weight procedure, the ultrasound test was conducted after each five impacts. The third stage covered statistical analysis of achieved results. The carried out experiments have shown that the ultrasound method combined with statistical methods are well used to monitor changes of mechanical properties of SFRCC used for road pavements or structure during dynamic destruction process. Time needed for the ultrasound wave to pass through a composite was main information about process of destruction occurring during an impact test (internal cracks in the composite structure make the way that ultrasound wave propagates longer comparing to undamaged structure of the composite). The results of the ultrasound propagation time measurements were analyzed based on a statistical approach.