EXPERIMENTAL INVESTIGATION OF UTILIZING STEEL FIBER AS CONCRETE REINFORCEMENT IN BRIDGE DECKS

Abstract

Research on utilizing steel fiber vs concrete reinforcement in bridge deck to replace more traditional reinforcing bars is sparse, therefore a research into this topic is interesting to identity opportunities for speeding up of construction by avoiding laying and tying reinforcement and verifying clear cover to reinforcing bars which is one of the most time-consuming processes involved in construction. This study investigates the efforts of steel fiber on the bridge deck from the strength and economical implementation. Four concrete mix design with vary steel fiber dosages of 0.0%, 0.5%, 1.0%, and 1.5% used in this study. The physical properties of steel fiber reinforced concrete were calculated through various tests at the Civil Engineering Laboratory Building. In total, 12-cylinder specimens of 4-inch diameter and 8-inch height, 12-cylinder specimens of 6-inch diameter and 12-inch height, 12- beam specimens of 6x6x20 inch and 12-slabs 45x20x3.5 inch were produced and tested after 28 days of curing. The specimens were tested for their compression, modules of rapture, flexural behavior as well as the split tensile test. The experiments revealed that the increase in the dosage of steel fiber fraction increases the compressive strength of the concrete by 17.4%, 23.5%, and 19.6% respectively for normal weight concrete without steel fiber. The breakout strength of concrete in tension increased by 21.6%, 33.6%and 54.8% for 0.5%, 1% and 1.5% volume fraction of steel fiber in concrete respectively. It is also found that adding steel fiber improves the ductility of slabs specimens behavior, the area under the load-deflection curves increases compare with normal concrete. Also adding steel fiber to the concrete matrix decreases the crack width and preventing the sudden collapse as in normal concrete. The cost analysis showed that utilizing steel fiber as concrete reinforcement in bridge decks improved the opportunity for economical construction, speeding up construction, more corrosion resistant options over the conventional reinforcing bars as corrosion of reinforcing steel in the most common path to failure of the bridge deck.