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Experimental study of a reinforced concrete bridge pier strengthened with HPFRC jacketing
No full textAs 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
Experimental study of photocatalitic concrete products for durability of reinforced concrete
No full textPreliminary experimental study on the effects of surface-applied photocatalytic products on the durability of reinforced concrete
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Experimental study of photocatalitic concrete products for durability of reinforced concrete
No full textThis paper focuses on the topic of durability of reinforced concrete structures. The aim of the presented study is to use the photocatalytic activity of titanium dioxide in order to create a photocatalised system which, applied on the external surface of reinforced concrete structures, can constitute a protective barrier. To this purpose suitable experimental tests have been carried out able to verify the efficacy of the photocatalytic activity with respect to the durability of reinforced concrete elements in terms of carbonation of concrete and corrosion of reinforcing steel
Sottofondo alleggerito resiliente in conglomerato cementizio con gomma riciclata da pneumatici fuori uso a ridotto rumore da calpestio
No full textSottofondo alleggerito resiliente in conglomerato cementizio con gomma riciclata da pneumatici fuori uso a ridotto rumore da calpestio
No full textPreliminary experimental study on the effects of surface-applied photocatalytic products on the durability of reinforced concrete
No full textThe aim of this paper is to assess, by the results of suitable experimental tests, the durability performances of surface-applied concrete layers that incorporate a photocatalytic material such as titanium dioxide. The use of photocatalytic materials for air purification has been developing rapidly in the last decades. Within this framework, the proposed experimental study is particularly significant considering that, although there are many advantages in applying photocatalytic construction materials, during the TiO 2-photocatalysis a large variety of organics, viruses, bacteria, fungi, algae can be totally degraded and mineralized to CO2, H 2O and harmless inorganic anions. The mineralized amounts of CO 2, deriving from both the photocatalytic oxidation itself and the external ambient, can progressively activate a chemical deterioration due to carbonation. It is then important to investigate the resistance properties of photocatalytic concrete products against carbonation. The effects of the photocatalytic activity on the durability of concrete have been assessed by using accelerated carbonation and corrosion of reinforcing steel tests. In order to keep the photocatalytic process ongoing, specimens with finish coatings containing TiO2 were put in direct contact with air (water in the form of humidity) and were subjected to light radiation. Results show that photocatalytic concrete products applied on the surface of concrete improve the property of carbonation resistance and reduce the corrosion propagation rate of reinforcing bars with respect to the case of cement coatings without any photocatalysts. The adopted experimental procedure can give a first contribution in order to understand if the photocatalytic activity of titanium dioxide creates a photocatalysed system acting as a protective barrier against the deterioration processes
Enhanced seismic response of a bridge pier strengthened with UHPFRC
No full textThe increasing age of Reinforcing Concrete (RC) road transport infrastructures, built mainly between the 60s and the 70s, is quickly becoming a key theme for the future development of constructions in many industrialized countries. It is believed that, given the age of the RC constructions, the increased traffic loads, and the growing awareness of seismic risk, there is a significant need for intervention in our country. The vertical elements, such as abutments and piers, are the parts of these structures more susceptible to seismic loading and the more exposed to the environment. During the last few years, new structural materials were developed and proposed to the market so that they are now ready for the national and international structural codes. Repairing, strengthening or seismic retrofitting RC structures with Ultra High Performance Fiber Reinforced Concrete (UHPFRC) offers a valuable opportunity to increase both seismic response and durability of these elements. This study demonstrates experimentally the possibility to enhance the seismic response of a RC bridge pier by means of the application of a thin layer of UHPFRC around the element
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