Confined concrete elements with PBO-FRCM composites

The paper summarizes the current knowledge on PBO-FRCM (p-Phenylene Benzobis Oxazole Fibre Reinforced Cementitious Matrix) confined concrete elements that have been acquired on the basis of experimental investigation. The strengthening effectiveness as well as the behavior of PBO-FRCM confined concrete elements have been evaluated. The impact of the intensity of the strengthening on the operational effectiveness of compressed elements have been compared. The analyses have been based on the results of the author's own investigation as well as on those available in the references. Test results of cylindrical specimens and specimens with square cross-sections were compared. The elements were reinforced with 1-4 layers of horizontally aligned PBO mesh. The compressive strength of non-reinforced concrete determines the effectiveness of the PBO-FRCM strengthening. The best strengthening effects are obtained for lower compressive strengths, at the identical intensiveness of transverse strengthening. The strength of confined concrete elements rises directly proportionally, jointly with the increase in the reinforcement ratio. The PBO-FRCM confined concrete core has limited capabilities of compressibility whereupon the exhaustion of the carrying capacity and the destruction of the element follow. The presence of the strengthening with the PBO mesh affects the longitudinal stiffness and the reduction level of elastic modulus, jointly with the rise in compressive stresses. The information obtained has broadened the knowledge on the subject matter under consideration and has determined the directions of further research work.