Étude du comportement structural de poutres et de dalles de ponts en béton armé d'une nouvelle armature à base de fibre de basalte sous charge statique

摘要

Abstract: The advances in fiber-reinforced-polymer (FRP) technology have spurred interest in introducing new fibers, such as basalt FRP (BFRP), which has the potential to offer an efficient solution when implemented in concrete structure, such as corrosion resistant, durable and cost-effective. Furthermore, the available design codes and guides do not provide any recommendations for the use of BFRP bars since fundamental studies and relevant applications are still limited. Therefore, investigations are needed to characterize and understand the behavior of BFRP bars in concrete members. Consequently, the main objectives of this experimental investigation are to evaluate the short- and long-term characteristics of newly developed BFRP bars, as well as evaluate the structural performance of these new bars as internal reinforcement for concrete beams and bridge-deck slabs to introduce these new reinforcing bars to the design codes and guides. The experimental tests were completed through three parts. The first part was conducted on three newly developed BFRP bars and tendons to investigate their physical and mechanical properties. Durability and long-term performance were assessed by conditioning the BFRP bars in an alkaline solution simulating the moist concrete environment to determine their suitability as internal reinforcement for concrete elements. Thereafter, the properties were assessed and compared with the unconditioned (reference) values. The second part of this study was conducted on seven full-scale edge-restrained concrete bridge-deck slabs simulating actual slab-on-girder bridge-deck that is commonly used in North America to evaluate the performance of concrete bridge-deck slabs reinforced with BFRP and steel bars. The deck slabs measured 3000 mm long × 2500 mm wide × 200 mm deep. The slabs were tested up to failure under single concentrated load acting on the center of each slab simulating the footprint of sustained truck wheel load. The punching shear capacities were predicted using the available provisions, and compared with the experimental results. The third part of this study included testing of fourteen concrete beams of 3100 mm long × 200 mm wide × 300 mm deep to investigate the flexural behavior and serviceability performance of sand-coated and ribbed BFRP bars in concrete beams. The beams were tested under four-point bending over a clear span of 2700 mm until failure. The results are introduced and discussed in terms of cracking behavior, deflection, flexure capacity, and failure modes. In addition, the bond-dependent coefficient (kb) of the BFRP bars was determined and compared with the recommendations of the current FRP design codes and guides. The findings of this study concluded the feasibility of producing BFRP bars meet the requirements of the current FRP standards. Also, the test results revealed that the BFRP bars had good mechanical behavior and could be placed in the same category as grade II and grade III GFRP bars. Moreover, the behavior of the concrete bridge-deck slabs and beams reinforced with BFRP bars was quite similar to the counterparts reinforced with glass- and carbon-FRP bars and the available FRP provisions are applicable for BFRP bars. The beam test results yielded an average bond-dependent coefficient (kb) of 0.76±0.03 and 0.83±0.03 for the sand-coated and ribbed BFRP bars, respectively.