Browsing by Department "University of Naples Federico II"

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    Bituminous Binder and Bituminous Mixture Modified with Waste Polyethylene
    (2023) Tušar, Marjan; Poulikakos, Lily D.; Kakar, Muhammad Rafiq; Pasquini, Emiliano; Pasetto, Marco; Porot, Laurent; Wang, Di; Cannone Falchetto, Augusto; Carter, Alan; Orozco, Gabriel; Riccardi, Chiara; Vasconcelos, Kamilla; Varveri, Aikaterini; Jing, Ruxin; Pinheiro, Gustavo; Hernando, David; Mikhailenko, Peter; Stoop, Jan; Wouters, Lacy; Miljković, Miomir; Orešković, Marko; Viscione, Nunzio; Veropalumbo, Rosa; Saboo, Nikhil; Lachance-Tremblay, Éric; Vaillancourt, Michel; Bueche, Nicolas; Dalmazzo, Davide; Moreno-Navarro, Fernando; Lo Presti, Davide; Giancontieri, Gaspare; Slovenian National Building and Civil Engineering Institute; Swiss Federal Laboratories for Materials Science and Technology; University of Padova; Kraton Chemical B.V.; Department of Civil Engineering; École de technologie supérieure; University of Pisa; Universidade de São Paulo; Delft University of Technology; University of Antwerp; University of Niš; University of Belgrade; University of Naples Federico II; Indian institute of Technology Roorkee; Bern University of Applied Sciences; Polytechnic University of Turin; University of Granada; University of Palermo
    RILEM TC-279 WMR task group TG 1 studied the performance of waste Polyethylene (PE) in bituminous binders and bituminous mixtures. Several laboratories participated in this study following a common protocol. Locally sources aggregates and bituminous binder and same source of waste PE were utilized. The binder experiments showed that at high temperatures, using MSCR tests, PE modified blends had better resistance to permanent deformation in comparison to the non modified binder. Whereas at intermediate temperatures, using the LAS tests, fatigue performance of the PE blends could withstand more loading cycles under low strains; however, it could sustain less loading cycles under high strains due to the increase in brittleness. Dry process was used for the mixture experiments in order to bypass the stability and inhomogeneity experience that was observed at the binder scale. The PE modified mixtures showed improved workability and increased strength. The higher the PE dosage, the higher the ITS increase with respect to the values measured for the control materials (i.e., without any plastic waste) thanks to the improved cohesion of the plastic modified mastic. The stiffness experiments tended to show an improved performance with a lower time dependence and a higher elasticity when plastic was added. The cyclic compression tests demonstrated a reduced creep rate along with a higher creep modulus thanks to the addition of PE; similar conclusions can be drawn from the experimental findings coming from wheel tracking test. Furthermore, acceptable and often improved moisture resistance was observed for PE modified materials.
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    Wake waves of a planing boat : An experimental model
    (American Institute of Physics Publising LLC, 2022-03-01) Tavakoli, Sasan; Shaghaghi, Poorya; Mancini, Simone; De Luca, Fabio; Dashtimanesh, Abbas; Department of Mechanical Engineering; University of Melbourne; FORCE Technology; University of Naples Federico II; Tallinn University of Technology
    The wake waves generated by the steady movement of a planing hull are analyzed by means of towing tank tests. Two sets of waves, including divergent and transverse waves, are identified and then analyzed. The wave period of the divergent waves is seen to decrease by the increase in speed of the vessel. These waves are seen to damp temporally. The mechanisms that lead to damping of the divergent wave were found to depend on the wave orbital Reynolds number in semi-planing regime, though that of in-planing regime is a function of the Reynolds number of the boat. The wake angle is seen to decrease with the increase in Froude number, the rate of which becomes relatively large in-planing regime. Transverse waves are captured through measurements, and it is shown that while their period is longer than those of the divergent waves, they are not noticeably damped. Throughout the spectral analysis, it is demonstrated that divergent waves reach a higher level of nonlinearity by the increase in Froude number and, hence,the wave energy is distributed over a boarder range of frequency. The height of the transverse wave is observed to become lower by the increase in speed, but as the towing speed increases, the probability density function curves of surface elevation deviate more and more from the Gaussian distribution.