Tensile Strength of Basalt Fiber Reinforced Plastic (BFRP) Rebar

Basalt is a natural hard, dense, dark brown to black volcanic igneous rock. It is the most common rock type in the earth’s crust. Its origins are at a depth of hundreds of kilometers beneath the earth and reach the surface as molten magma. The volcanic rock in general is widely available in various regions of the world. Basalt finds its way into wide application in industry as abrasion, wear and chemical resistant materials. In recent years a new type of FRP composite material has been developed called Basalt Fiber Reinforced Plastic (BFRP) material. The characteristics of this material have various beneficial features such as high strength-to-weight ratio, lower specific weight and excellent corrosion and fatigue resistance. Nowadays this material is finding their way to more novel applications in relation to civil engineering structures. The use of Basalt in rebar applications, the physical testing results have shown to have ultimate tensile strength which is up to 4 times higher than the tensile strength of conventional steel rebar.

For the tensile testing of BFRP composite rebar, it is important that the specimens are prepared with tabbed ends in order to guarantee an adequate clamping of the specimen. This ensures that specimen breaks occur within the gauge length and not within the jaw face. For this test, we recommend the use of the model 5985 floor test system, 250kN capacity for tensile testing applications.

Before starting the test, the specimen is measured, then placed into 250kN hydraulic wedge grips. During the gripping process of the specimen, specimen protect feature is selected that allows you to set a load threshold that won't be exceeded until the test is started. A strain gauged clip-on extensometer; 25mm gauge length with 10% travel capability is attached to the specimen.

Bluehill 3 test software package is used to input specimen parameters, set the desired test speed control, automatically calculate the desired results and statistics, and finally produce a test report.