Measurement of the Pull-out Force at Different Rates of Loading

With the objective of understanding the reinforcing mechanisms of fibers in steel fiber reinforced concrete, the adherence between the fiber and the matrix is studied by conducting pull-out test of fibers from a cementitious matrix. In this paper the effect of factors such as loading rate, inclination of fibers, and number of fibers have been investigated. An innovative measurement system is developed for high rates. It was experimentally obtained that by increasing the rate of loading, both pull-out resistance and slip at peak were increased. Peak pull-out force presents a higher rate sensitivity for a higher number of fibers. The lower the number of fibers the higher the slip at peak rate sensitivity. Regardless of the number of fibers a higher rate sensitivity for inclined fibers was observed.