1,721,124 research outputs found
Ruolo dei meccanismi di aderenza e di frattura nella fase di esercizio degli elementi di conglomerato armato
No full textSul comportamento di elementi semplicemente tesi in conglomerato cementizio armato placcati
No full text
The work of fracture in the eco-mechanical performances of structural concrete
No full textthe elastic approach of eco-mechanical performances of concrete is presented. In particular the fracture energy aspects are investigated, taking into account aggregates and fibre
Modelling masonry arches under fire
No full textMasonry structures, often found in several historical and artistic buildings, need to be assessed not only at the serviceability and ultimate limit states, but also under accidental and extreme actions. However, masonry arches under fire are not taken into consideration by Part 1-2 of Eurocode 6, where only rules on vertical walls are reported. In addition, neither theoretical nor experimental research activities on these structures are reported in the current literature. For this reason, an advanced calculation method, capable of predicting the nonlinear behaviour of masonry arches subjected to elevated temperatures, is herein presented. As a result, a range of admissible loads can be defined for a pre-established fire scenario. The maximum load of the range decreases as the time of fire exposure increases, whereas the minimum load, which guarantees the structural stability of the arch, increases with tim
A new strategy to reduce the environmental impact of FRC
No full textConcrete cylinders are subjected to uniaxial compression tests in order to define the whole mechanical response of different mixtures, including the strength and the post-peak ductility. With respect to traditional concretes, the deleterious effects produced by the reduction of cement content (and thus of dioxide carbon emission) can be mitigated by adding mineral admixtures and/or fibers. For instance, fly ashes and silica fumes can increase the compressive strength, even in the presence of a high water/cement ratio. Similarly, low amounts of steel fibers (less than 1% in volume) can drastically enhance the post-peak toughness. Starting from these experimental observations, a new eco-mechanical index is here introduced with the aim of defining an effective strategy to reduce the environmental impact of concrete, without any mechanical detriment. The theoretical and the experimental analyses here developed seem to confirm that the idea of tailoring a new generation of fiber-reinforced concrete, capable of maintaining high mechanical properties with a reduced amount of cement, is not a chimer
Eco-mechanical performances of cement-based materials: An application to self-consolidating concrete
No full textThe environmental performances of concrete structures have been largely investigated in the last years. However, mechanical behavior and ecological aspects are not always combined in these analyses. Thus, two low-carbon footprint self-consolidating concretes have been subjected to uniaxial compression loads, in order to measure the strength and the dissipated energy during failure. Starting from these tests, new eco-mechanical ratios are herein introduced with the aim of tailoring eco-friendly concrete with acceptable mechanical performances. As a result, the best structural and environmental performances can be achieved not only by replacing cement with mineral admixtures, but also adding steel fiber
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