Search

La natura della corte di cassazione italiana � oggi oggetto di profondi cambiamenti. La presente Tesi di Dottorato cerca di leggere in maniera consapevole questa metamorfosi ripercorrendo gli accadimenti che hanno condotto al formarsi del modello della cassation francese, in ancien r�gime e nel contesto rivoluzionario, e a quello dello stare decisis, strutturatosi a partire dalle vicende del Seicento inglese e affermatosi nel XIX secolo in coerenza con la riforma delle strutture giudiziarie.

Calcium sulphoaluminate (CSA) cement became progressively more used in recent years, considering both the mechanical per-formance and the environmental aspects linked to the CO2 manufacturing emissions lower than ordinary Portland cement (OPC). In this study, the mechanical behavior of steel-reinforced concrete beams made using various binders, such as pure CSA or blends with OPC was investigated experimentally, in terms of flexural resistance, crack pattern (number, length and crack width). For this purpose, a mechanical characterization of the various concrete mixtures at early and later ages was performed. Moreover, an ad-hoc experimental set-up was designed in order to study the durability of structural beams for different concrete types, under specif-ic environmental and service conditions. The results showed a satisfactory behavior of the CSA mixtures when compared with the OPC reference mixture in terms of early age resistance, mechanical performance and crack evolution during the time.

The acid-base properties of selected derivatives of the [1,2,4]triazolo[3,2-c][1,2,4]triazole fused aromatic system have been investigated by UV–vis spectroscopy. Neutral heterobicycles (HL) exhibit amphoteric behavior (they can deliver the N–H proton forming the conjugated base L− and can accept up to two protons, forming the species H2L+ and H3L++) and show an unprecedented tautomeric switching upon protonation, as revealed by single crystal X-ray analysis and confirmed by theoretical calculations. By varying the groups attached at the heterocycle, a remarkable shift of pKai values, up to 5–6 units, is observed. In particular, with strong electron attractor groups at position 7 (e.g. p-nitrophenyl or pentafluorophenyl) the neutral compounds are stronger acids than phenol or p-nitrophenol.

The use of recycled steel fibres from waste tyres as reinforcement in concrete matrix appears a promising solution thanks to the performance of the material in terms of toughness and post-cracking behaviour. The main objective of this paper is to analyse the bond behaviour between Recycled Steel Fibre Reinforced Concrete (RSFRC) and steel bars and to compare the results with those of Industrial Steel Fibres Reinforced Concrete (ISFRC). The paper focuses on the characterization of the mechanical properties of concrete reinforced with short steel fibres from waste tyres and on the results of pull-out tests executed both on RSFRC and ISFRC. The experimental results, in terms of failure mode, maximum bond stress and bond stress versus slip behaviour are analysed and discussed. Finally a theoretical analysis of the bond-slip behaviour has been performed. The experimental results show as most of the known performance of the ISFRC can be extended to RSFRC. Referring to the bond performance, an improved behaviour of RSFRC with respect to ISFRC in terms of bond-slip law has been observed.

A study of the long-term behavior of plain and steel reinforced concrete elements made using pure CSA cement or blends with OPC cement was performed. The properties of five different concretes were experimentally evaluated at fresh and hardened state at early and later age, including the volume stability. The flexural response and crack pattern at different load steps of real scale reinforced concrete beams made using the same concrete mixtures were investigated performing bending tests. The crack widths detected during the bending tests were compared with those calculated using analytical formulation. Moreover, the long-term behavior in terms of crack patterns and mid-span deflections was monitored in time on analogous beam samples exposed to external environmental conditions and maintained under load levels simulating the service load. The obtained results have shown a good behavior of the concrete mixtures made with pure CSA cement and its blends with OPC in terms of mechanical and shrinkage behavior. A later development of the mechanical properties was detected for the CSA/OPC mixtures. A good agreement between the experimental crack width values and the analytical estimation according to international standard was found. The steel reinforced concrete beam made with 70/30 OPC/CSA mix shows the highest mid-span deflection.