Experimental study of fracture of lightly reinforced concrete beams

The experimental program reported in this paper was planned to investigate the sensitivity of lightly reinforced concrete beams to size and to steel-to-concrete bond properties. Forty-eight micro-concrete reinforced beams were tested; these were of three different sizes, reinforced with various amounts of both smooth and ribbed wires. Unlike the tests found in the scientific literature, the material properties and the parameters that characterize the steel-concrete interaction were all obtained from independent tests. Likewise, experimental errors due to material heterogeneity or incorrect setup of the tests were minimized so as to ensure a high level of control during the execution of the program. The experimental results exhibit maximum load size effect and a strong dependence on bond-slip properties. Beams with a large cover show a secondary load peak between cover cracking and steel yielding, which provides a hint as to the role of the reinforcement cover in the cracking process.