Comportamento de vigas protendidas confeccionadas com vergalhão BFRP e concreto com troca parcial por areia do mar

Abstract

Natural materials found in nature, such as sand and river water, are used worldwide in construction. Finding a replacement for these materials has been a challenge for the entire construction community, so that civil construction can become more sustainable. Lately, the use of concrete made with sand and sea water has gradually become an option, mainly due to the fact that the mechanical properties of these concretes have already been shown to be similar to those of common concrete. The sustainable use of sea-sand concrete (SSC) also serves to reduce the use of river sand, mainly for projects in coastal areas, which can result in the use of local materials, savings in transport costs, accelerating the efficiency of the work . However, the corrosion of steel reinforcement in these structures, caused by chloride ions, is still a worrying pathological manifestation. In recent years, the use of different forms of fiber reinforced polymer (FRP) reinforcement with SSC has been extensively investigated for the manufacture of highly durable marine structures. Among these studies, those that use (FRP) bars internally prestressed in concrete stand out. The aim of this study is to verify the flexural resistance capacity of concrete beams with washed sand and replacing 30% of the washed sand with sea sand, from Copacabana beach, prestressed with basalt fiber bars (BFRP). In relation to BFRP bars, the results of the tensile test showed a 20% lower resistance when compared to the information obtained from suppliers. The results of the tests carried out on the specimens show that both concretes presented similar compressive strength at 28 days. Regarding the comparison of the breaking load following the recommendations of ACI 440, with the experimental results, it was noted that the ACI formulations underestimated the results for beam 1 (experimentally a 13.2% higher result was found) and overestimated the beam 2 (the experimental result was 9.2% higher). When comparing the results obtained by the NBR 6118 formulations, the results were overestimated in both beams. Experimentally, the result obtained for beam 1 was 3.6% lower and for beam 2, 25.1% lower.