The Fiber Reinforced polymer (FRP) composites have always found its extensive application in defense and aerospace industries since the period of its inception.Nowadays they are finding their way to more novel applications in relation to civil engineering structures. They are characterized by various beneficial features such as high strength-to-weight ratio, lower specific weight and excellent corrosion and fatigue resistance. These properties have rendered the application of FRP materials as the internal as well as external reinforcement in civil-engineering structures to be a very fertile field of study.
This thesis presents the results of the experimental and analytical investigation
on the mechanical properties and their application as the internal reinforcement of the new type of FRP composite material called Basalt Fiber Reinforced Plastic (BFRP) material. The primary objective of the research was the identification of the important mechanical properties of the BFRP bars and their applicability as the internal reinforcement in the reinforced concrete beams. For the mechanical properties of the BFRP bars, the BFRP bars of three different sizes were considered. The provided bars were of nominal size of 3mm, 5mm and 7mm with the volume fraction of 44%, 52% and 41% respectively. For the study of bond-strength of the BFRP bars, three pull-out cylinder tests were conducted for each size. For the study of the flexural-application, fifteen different beams were studied, two of
them being the steel-reinforced beams. The study on the mechanical properties revealed the tensile-strength, rupture-strain and the longitudinal modulus of elasticity of the BFRP bars. From the pull-out cylinder test, a bond-slip model for the BFRP bars was proposed. From the beam tests, it was observed that the ACI 440 can predict the moment-strength of BFRP reinforced beams with reasonable accuracy. It was also observed that the original Branson’s equation provide the lower bound and the ACI 440 provides the upper-bound for the load-deflection curve for the BFRP reinforced beam. A relation for the effective moment of inertia for the BFRP beam was proposed for load-deflection analysis.