Study On The Bond Mechanism Of Deformed Steel Fiber And Concrete And Toughening Effect

Steel fiber reinforced concrete (SFRC) is superexcellent composites and with development of the use of it, many deformed steel fibers emerge as times require. Deformed steel fiber reinforcing and toughening is notable. The interface bond is the key to playing the reinforcing and toughening effect. However, now the study of bond strength is on the understanding phase. The paper is concentrated on the bond mechanism of deformed steel fiber and concrete and toughening effect. The main contents of my project are as follows.1. The paper designed the experiment of the bond strength between deformed steel fiber and concrete, probed into the shape and the mold of the specimen, making specimen, loading equipment and the methods.2. The research of the bond mechanism of deformed steel fibers and concrete. The main contents as follows:(1) The experiment research of the bond strength between deformed steel fibers and concrete. Basing on the results of the experiment, discuss the shape of the steel fiber, the matrix strength and the embedding angle are the important factors of the bond strength.(2) Analyze the dissipated energy during the pulling out and the factors of it.(3) Putting forward three kinds of fail model and the relevant formula of the peak pullout load. Basing on the results of the experiment, analyze the fail model of B-Fiber pulling out and present the formula of the peak pullout load which accords with the results of the experiment better.3. The research of the toughening effect of deformed steel fiber. The contents as follows:(1) Analyze and sum up the existing evaluating methods of toughness index of SFRC. The limitations of these methods are summarized and the principle of founding up the evaluation method of toughness index is given. Present the evaluation method of toughness index of SFRC-the toughness index after cracking and the Fracture-CMOD toughness index.(2) Basing on the experiment results, analyze the toughening effect of deformed steel fiber and probe into the bond mechanism of it.