No abstract

Europe and United States exert a worldwide influence in the field of concrete control, proof of this is that many countries adopt their regulations, due to lack of own regulations. When there are problems with concrete strength, cores are used, and this situation usually involves two or more parties with different views on the proper interpretation of the core results. An experimental study was carried out, with five lots of prototypes concrete slabs of 20, 30, and 35 MPa specified strength, 210 cylinders of 10 × 20 cm, 296 cores of 10 cm diameter, and slenderness 2, as well as temperature and maturity control. Estimated strength of cores and cylinders was compared according to the criteria of European standards UNE‐EN 13791 and the American code ACI 318. Tests were performed at 3, 5, 7, and 28 days. It is concluded that the European and American regulations present similar results for concretes with specified strength between 30 and 35 MPa, whereas in the range of 16–30 MPa, the European standard is more rigorous than the American Code, being the latter more favorable to the concrete producer.

No abstract

The negative effects of climate change are underway despite the global efforts to mitigate them and the future scenario are unsettling. Climate change poses critical challenges to urban environments and highlights the need for research its impacts on the built environment. One of the most significant effects of climate change on reinforced concrete structures is associated with the carbonation of these structures. The increase of parameters such as temperature and carbon dioxide jeopardise the degradation of such structures by carbonation-induced corrosion. This paper presents the results of the monitoring and analysis of a set of buildings that determine carbonation as the main degradation mechanism of structures in Paraguay. Through the application of a previously developed carbonation model, the worsening of the carbonation-induced degradation has been determined after considering the climate change effects in the coming 50 years. The outcomes of the study determined that the poor quality of the structures in Paraguay cause premature degradation in them. Furthermore, considering climate change effects, it has been determined that this phenomenon could accelerate corrosion failure times in reinforced concrete structures.