الفهرس 
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Abstract
This research aimed to develop a better understanding of the structural performance of basalt fiber-reinforced polymers (BFRP) reinforcing bars. The experimental program consisted of two phases, designed to evaluate the characteristics and the durability performance of BFRP bars under severe conditions.
This section summarizes the different phases of the research as follows:
Phase I: characterization of the mechanical properties of BFRP bars
This phase aimed to investigate the mechanical properties of BFRP bars. The tests were performed in accordance with ASTM standards, the results were judged in accordance to the requirements of the FRP specifications and codes such as CSA S807 [20], and ACI 440.6M-08 [22].
Phase II: Long-Term Performance of BFRP Bond Strength
One hundred and two ribbed BFRP control and conditioned specimens were tested under direct tensile pull-out tests. The long-term performance of BFRP bond behavior was investigated in accordance to ASTM standards using accelerated aging techniques in various chemical solutions (alkaline, and salts) at high temperatures for different periods of time to determine their durability when implemented in concrete elements.
5.2 Conclusions
Based on the experimental tests and the analysis of the results, the following conclusions were extracted from this research:
1- This research confirmed that the developed basalt FRP (BFRP) bars met the requirements of ACI 440.6M-08 and CSA S807-10 concerning their mechanical properties.
2- The exposure to the alkaline solution simulating the concrete environment had a negligible effect on the bond strength-end slip curves.
3- The exposure to the salt solution simulating the ocean water that exists in the climate of the coastal areas had a negligible effect on the bond strength-end slip relationships.
4- The rate of diffusion of aggressive solutions was directly proportional to the permeability of the concrete.
5- The governing cause for failure for both control and conditioned specimens was the interlaminar shear between the BFRP layers rather than the shear stresses at the interface between concrete and BFRP bar.
6- The adhesion to concrete was enhanced by swelling of the BFRP bar at the early stages of conditioning, but in the case of continuous conditioning, these stresses were reduced rapidly. The enhancement due to swelling of the bar depends on the absorption properties of the BFRP bar, which depend on the manufacturing quality, and the porosity of the concrete.
7- The fiber-resin interface is the key parameter in the degradation process of the BFRP bars bond. The enhancement of the fiber-resin interface will lead to producing BFRP bars with improved durability properties.
8- Increasing the bonded length increased the reduction exhibited in the bond strength when exposed to the alkaline solution (20% for 7.5d, 13% for 5.0d, and 7% for 2.5d) as the degradation of the bar surface was the governing cause of failure.
9- Decreasing the concrete compressive strength increased the reduction exhibited in the bond strength when exposed to the alkaline solution (17% for 25 MPa, 13% for 45 MPa, and 9% for 60 MPa).
5.3 Recommendations for Future Work
This study aims to increase the potential of using BFRP bars in constructions through providing a better understanding of the BFRP bars’ behavior. Further research should be devoted to investigating the effect of ultra-high-strength concrete on the bond durability, the bond behavior of large-scale specimens under severe conditions, and the effect of improvement of the BFRP quality on the bond behavior.