Quality control methodology for composite FRP rebars

Abstract

The increasing demand on reinforced concrete infrastructure, coupled with environmental challenges, results in accelerated degradation evident for example by corrosion. Composite FRP rebar used to reinforce concrete structures can address durability challenges, making progress towards a safe and resilient built infrastructure. While FRP rebars have been commercially available for at least two decades, with the foreseen increasing demand for its use, establishing reliable and effective quality control (QC) methodology to provide assurance of the manufactured composite rebar properties is paramount for full implementation of this concrete reinforcing technology; and assure extended service life, safety and reliability of concrete infrastructure. This study first presents an initial QC assessment criterion, which is applied to existing QC standard specification, and then validates an alternative methodology based on a flexural test of FRP rebars as a response to the need of additional reliable, effective and rapid tests that FRP rebar manufactures can implement to assess the continued quality of pultruded rebars during production. To this end, various parameters where preliminary evaluated including, two test configurations, span-to-depth ratios, eight manufactures and three different rebar diameters per manufacture (nominal 9.5 mm, 12.7 mm, 25.4 mm). Overall the selected test procedure was validated with over 100 tests and results compared and correlated to FRP rebar tensile properties. Based on the results, reliable and valid physio-mechanical properties can be determined from the test protocol, which can be directly related to design properties. The test is time- and cost- effective and can be adopted to obtain quantitative quality control data in as little as seven minutes.