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High‐Performance Fibre‐Reinforced Concrete (HPFRC) jacketing technique provides a sustainable solution to the constantly growing infrastructure degradation. This paper investigates the effect of HPFRC jacketing solution on strength enhancement of plain concrete. The experimental work included 23 samples, 15 of which were jacketed with HPFRC, and the remaining 8 were used to measure the unconfined strength. The key parameters were jacket thickness (25 mm, 35 mm, and 45 mm) and pre‐damage level (40% and 80%). The results show that jacketed columns exhibit a ductile behaviour. It is found that a 25 mm HPFRC jacket increases the compressive strength by 31%. Moreover, increasing the jacket thickness further enhances the compressive strength. However, the enhancement rate gradually decreases with increasing the jacket thickness. The results from sensor technology used on each concrete layer revealed that the lateral strain of jacketed concrete at a given axial strain was greater than that of unjacketed concrete, indicating an increased rate of dilation for the jacketed concrete. The results show that strengthening of existing columns at their mid‐service life (i.e., 40% pre‐damaged) is as effective as strengthening of new columns. The obtained knowledge suggests that HPFRC jacketing solution has a great potential to revolutionise infrastructure rehabilitation techniques. [ABSTRACT FROM AUTHOR]

The post‐cracking tensile behavior of polypropylene fiber reinforced concrete (PFRC) was investigated through an experimental study; special attention was devoted to the effects of fiber distribution and orientation on samples performance. In this regard, an experimental campaign based on uniaxial tensile tests (UTTs) on notched cylinders as well as three‐point bending tests (3PBTs) on notched beams was carried out. Uniaxial post‐cracking tensile laws retrieved both directly (UTTs) and indirectly (3PBTs) were compared. In the latter case, the fracture energy was higher because of the strongly dependency between PFRC post‐cracking performance and fiber distribution and orientation. In addition to cast cylindrical samples, core samples were directly drilled from the beams and tested under UTTs in order to compare their post‐cracking performance with that obtained by flexural standard tests on notched beams. [ABSTRACT FROM AUTHOR]

• Reduced scale (1:4) bridge pier reinforced with UHPFRC jacketing was investigated. • Flexural capacity increased more than 50% with respect to the unreinforced element. • Failure was reached with appreciable displacements, corresponding to 3,4% drift. • Small crack opening and low porosity of concrete enhance durability of the pier. As a consequence of material degradation, increasing traffic loads and seismic actions, a large number of existing reinforced concrete bridges are no longer safe and may represent a risk for human lives and for the robustness of the road network. Replacement of these bridges is often not practical given the cost of demolition and rebuilding in addition to the social costs of traffic interruption. As an alternative to the replacement of the entire structure, the service life of a bridge can be extended by adopting reliable strengthening techniques. Among these strengthening techniques is High Performance Fibre Reinforced Concrete (HPFRC) jacketing, which was experimentally investigated in this research project. The mix design of HPFRC was studied with the goal of producing a material with enhanced mechanical performance as well as excellent rheology. In this study, the bridge pier studied was subjected to cyclic horizontal loads both before and after strengthening, up to failure. Experimental results show that the HPFRC jacketing remarkably increased the bearing capacity of the pier as well as its ductility. The jacketing also enhanced the structural response in terms of crack control, which significantly governs the structural durability. [ABSTRACT FROM AUTHOR]

Highlights: [•] The effect of photocatalytic products on concrete durability was tested. [•] The photocatalytic activity of titanium dioxide was used. [•] The durability of concrete in terms of carbonation resistance was improved. [•] Surface-applied photocatalytic products provide protection for steel bars in concrete. [ABSTRACT FROM AUTHOR]