Self-sensing and strengthening effects of reinforced concrete structures with near-surfaced mounted smart basalt fibre–reinforced polymer bars

Abstract

A new retrofitting system is proposed for reinforced concrete structures with application of near-surfaced mounted smart basalt fibre–reinforced polymer bar. The distributed optical fibre sensing technology, namely pre-pump pulse Brillouin optical time-domain analysis, is applied as the sensing technology for the smart bar. Then the proposed system is explained in detail from both self-sensing and strengthening. Finally, some experiments were implemented with reinforced concrete beams to verify the actual effects. From the results, it is concluded that the ultimate strength and the stiffness after steel rebar yielding can be increased obviously due to the high strength and ultimate strain of the smart basalt fibre–reinforced polymer bar. Meanwhile, the structure strain distribution can be measured with the smart basalt fibre–reinforced polymer bar, with which some key parameters can be well assessed, such as crack location, crack width, displacement and bending moment. However, the self-sensing effects indeed have been obviously influenced by the strain measurement accuracy especially after concrete cracking. Therefore, it is meaningful to improve the sensing accuracy especially for complicated strain. Additionally, some prestress upon the smart basalt fibre–reinforced polymer bar can improve both sensing and strengthening performance.