Flexural strengthening of reinforced concrete beams using engineered cementitious composite panels using artificial pozzolan, glass mesh, and grooving method

This research investigates, for the first time, the effects of high-silica synthetic pozzolan as a primary component in the mixing design of engineered cementitious composites (ECC). The study focuses on the behavior of reinforced concrete (RC) beams retrofitted with precast or in-situ glass grid-reinforced ECC (GGR-ECC). Longitudinal and transverse grooves were applied as surface preparation to enhance the bonding of GGR-ECC on RC beams subjected to four-point bending tests. Five RC beams were tested: one control and four retrofitted beams. Results showed that the optimal mixing design, which included 205 kg/m³ synthetic pozzolan, achieved maximum compressive and flexural strengths of 38 and 5.15 MPa, respectively, and a high energy absorption capacity. Moreover, beams retrofitted with in-situ GGR-ECC using transverse and longitudinal grooves demonstrated increased load-carrying capacities of 33.1 % and 19.6 %, respectively, compared to the control beam. The beam strengthened with precast GGR-ECC using the longitudinal grooving showed a 28.5 % enhancement in load-carrying capacity. Further analysis revealed that the in-situ GGR-ECC panels significantly enhanced the ductility of the RC beams. The ductility index of the beam strengthened with in-situ GGR-ECC through the transverse grooving method increased by 2.4 times compared to the one retrofitted with the same condition but in precast form, and by 3.7 times compared to the one strengthened with the same condition but with longitudinal grooves. Finally, theoretical equations were developed to predict the flexural capacity of RC beams retrofitted with GGR-ECC panels, achieving an error margin of less than 6.5 %, indicating reliable predictive accuracy.