TOUGHNESS ENHANCEMENT OF AIRFIELD CONCRETE PAVEMENT BY USING SHORT FIBER

摘要

Few efforts have been made to understand the progressive failure of concrete pavements, especially the crack propagation in the concrete materials. More detailed information about concrete material, such as its fracture properties, is required along with the strength to better quantify crack propagation rates of varying concrete mixture proportions and constituents. The susceptibility of concrete pavements to crack growth may be eliminated by adding short steel or glass fibers. Therefore, an experimental study was carried out to investigate the effect of adding short fiber, steel or glass, in controlling the fracture energy of concrete. The analysis was conducted for a constant fiber length of 25 mm. The flexure test of single edge notched as well as unnotched specimens was performed using three-point bending configuration. Four different values of crack-depth ratios were considered, namely 0, 0.1, 0.25, and 0.4. For the same crack-depth ratio, results show that the maximum value of crack mouth opening displacement, and value of curvature in steel-fiber-reinforced concrete (SFRC) were greater than those in glass-fiber-reinforced concrete (GFRC). However, the beam-carrying capacities of GFRC are higher than those of the SFRC for all crack-depth ratios. In general, the fracture energy of the SFRC is greater than that of the GFRC. It is noteworthy that the last portion of moment-curvature curve of the GFRC is steeper than the SFRC curve, thereby indicating that the SFRC is relatively more ductile. The fracture energy depends on the fiber type and crack-depth ratio. Moreover, the fracture energy calculated from notched beam with high crack-depth ratios was found to be more stable and reliable.