1,720,983 research outputs found
Climate change mitigation investigating asphalt pavement solutions made up of plastomeric compounds
No full textPromoting resource conservation in road flexible pavement using jet grouting and plastic waste as filler
No full textThe circular economy aims to change the paradigm in relation to the linear economy by limiting the environmental impact and waste of resources, as well as increasing efficiency at all stages of the product economy; the recent warnings about waste pollution and the limits of natural resources are encouraging its development. The purpose of this research is to investigate the potential environmental and mechanical benefits of reusing two different waste, namely jet grouting waste (JGW) and plastic waste (PW) for producing hot asphalt mastics made up of bitumen and filler: the JGW comes from the soil consolidation activities during pavement construction, while the PW, a mixture of high-density polyethylene, low density polyethylene, polypropylene and polyethylene terephthalate derives from a plastic recycling plant. First, three mastics engineered by keeping constant viscosity and a filler over bitumen ratio of 0.3 for the asphalt mastic with limestone filler (LM), 0.29 for the mastic with JGW (JGWM) and 0.1 for the solution containing PW (PWM), were investigated through a dynamic shear rheometer to explore their rheological behavior. Second main step concerned the life cycle assessment (LCA) of the three asphalt mastics that, in turn, are included into the base layer of a flexible road pavement by following ReCiPe impact assessment methodology. Primary results in terms of mechanical performance demonstrated that: 1) JGWM outperformed LM in terms of complex shear modulus, which resulted 19% higher than that of LM in the temperature range below 30 °C, and 2) PWM returned on average 30% lower non-recoverable creep compliance at 50 °C under 0.1 and 3.2 kPa than remaining solutions under analysis. LCA outcomes showed, on the one hand, that PWM had the best environmental performance, expressing the lowest damage to human health, ecosystems and resource availability indicators, returning on average 34% and 19% lower indicators than LM and JGWM, respectively. On the other hand, JGWM still represented an overall improvement of the environmental performance compared to LM, returning the best performance in terms of damage to human health, which lowers by 23%, due to the reduction of the output waste stream
LCA of recycled bituminous mixtures containing jet grouting waste
No full textThe study aimed to compare mechanical and environmental performance of four solutions for base layer of a flexible pavement with hot and cold technology, with and without the reemployment of jet grouting waste obtained from land consolidation work during the construction of underground tunnels. The laboratory investigation provided cold bituminous mixture with optimum performance mechanical compared to hot bituminous mixtures. The environmental evaluation has been focused on Life Cycle Assessment (LCA) taking into account all manufacturing process from cradle to laying of flexible pavement having as base layer the four mixtures investigated
Assessment of eco-friendly modified asphalt mixture using PMA methodology
No full textThe research program aims to define a new methodological procedure to design eco-friendly modified asphalt using PMA methodology in substitution to PMB technology. In the starting phase two different mixes were optimized using SUPERPAVE methodology, and the ITS value was evaluated. The first mixture is a Traditional Mixture (TM) and another one is an Modified Mixture (MM) with the addition of 5% (by total mass of bitumen) of polymeric compound using PMA technology. From the ITS analysis, the modified mixture shows an ITS value higher about of 20% than traditional Hot Mix Asphalt
Surface monitoring of road pavements using mobile crowdsensing technology
Full text linkPavement-surface characteristics should be considered during road maintenance for safe and comfortable driving. A detailed and up-to-date report of road-pavement network conditions is required to optimize a maintenance plan. However, manual road inspection methods, such as periodic visual surveys, are time-consuming and expensive. A common technology used to address this issue is SmartRoadSense, a collaborative system for the automatic detection of road-surface characteristics using Global Positioning System receivers and triaxial accelerometers contained in mobile devices. In this study, the results of the SmartRoadSense surveys conducted on Provincial Road 2 (SP2) in Salerno, Italy, were compared with the Distress Cadastre data for the same province and the pavement condition indices of different sections of the SP2. Although the effectiveness of the crowdsensing-based SmartRoadSense was found to vary with the distress type, the system was confirmed to be very efficient for monitoring the most critical road failures
Influence of fly ashes as alternative filler in asphalt mixtures
No full textThis study defined the mechanical/volumetric properties and the environmental compatibility of bituminous mixtures containing fly ashes as alternative of traditional limestone filler. The research study is articulated in different steps as follows: a) characterization of fly ashes according to UNI EN 1303 Standard; b) environmental compatibility analysis of mastics containing fly ashes by using a leaching test; c) stiffness evaluation of the mastics containing limestone and fly ash filler by static testing, as Delta Ring and Ball Test, and dynamic testing, as Frequency Sweep Test; d) mechanical and volumetric characterization of asphalt concrete containing fly ashes and limestone filler starting from a phase of mix design of hot mix asphalt mixtures. The characteristics of rigidity of the bituminous conglomerates has been evaluated using the HMA optimal mixture analysis through a dynamic test with a sinusoidal load. Then, the ability of two different HMA to endure a permanent deformation was evaluated by a Repeated Load Axial Test. The results has shown that mixtures of Hot Mix Asphalt with flying ashes as filler, compared to Hot Mix Asphalt containing limestone filler, is preferred in terms of mechanical performances and relevant environmental compatibility evaluated with a leaching test
Rheological properties comparing hot and cold bituminous mastics containing jet grouting waste
No full textThe use of reclaimed asphalt pavement is a practice that is adding significant environmental value to road technologies, not only due to the reduction of materials sent to landfill but also because of the mechanical properties of the reclaimed asphalt (RA) that can be reused. This research focuses on the rheological properties of hot and cold bituminous mastics made up as follows: (1) hot mastics mixed with limestone filler (LF) and bitumen, (2) hot mastics, made from bitumen mixed with jet grouting waste (JW), a mixture of water, cement, and soil derived from land consolidation work in underground tunnels, and (3) hot mastics mixed with LF and JW as filler and bitumen. Three different ratios (0.3, 0.4, and 0.5) of filler per unit of neat bitumen (B50/70) were studied. The same number was used for mixing cold mastics, by using an appropriate laboratory protocol designed since the adoption of a cationic bituminous emulsion. A total of 18 mastics were prepared and investigated. The comparison was carried out using the frequency sweep (FS) test, analysing shear modulus G∗, applying the multistress creep and recovery (MSCR) test (40°C and 60°C) as well as the delta ring and ball (ΔR&B) test, focusing on two main issues: (1) the stiffening effect caused by the filler type used for mixing each mastic, and (2) a comparison, in terms of stiffening effects and nonrecoverable creep compliance (Jnr) of hot and cold mastic performance to highlight JW reuse in mastics. The results showed that the best G∗ performance at test temperatures higher than 30°C is given by cold mastic after 28 days of curing time when JW is added to LF and bitumen. The lowest Jnr value was 40°C and 60°C for the same mastic
Investigating the environmental and mechanical properties of sustainable asphalt mastic solutions for road flexible pavements
Full text linkThe circular economy is restorative in nature, and it aims to maintain the utility of products, components and materials for as long as possible while also retaining their value. It thus minimizes the need for new inputs of virgin materials and energy, while reducing environmental pressures linked to resource extraction, emissions and waste management. The research focus on the investigation of an innovative procedure for reusing the jet grouting waste (JGW) obtained from soil consolidation activities to produce high-performing sustainable road asphalt mastics (filler plus neat bitumen). The mastics under analysis were made at three different filler over bitumen ratios of 0.5, 1 and 1.5, in particular six were obtained with neat bitumen and other six at the same f/b ratios mixed with an aged bitumen after the RTFO procedure. The rheological properties of the mastics were investigated using a dynamic shear rheometer, and the performance of the innovative mastics was compared with that of the neat bitumen and traditional mastics made up of bitumen and limestone filler (LF). The main results of the initial step of the analysis showed that, at temperatures from 0 to 30°C, the shear moduli of the mastics containing JGW (MJGW) averaged 30% higher than the limestone mastic (ML) blended with an f/b ratio of 0.30. The life-cycle assessment impact category indicators were then calculated, highlighting the considerable environmental benefits of the innovative hot asphalt mastics in question. The primary outcomes showed that compared with the asphalt mastics containing LF, the asphalt mastic solution lowered terrestrial ecotoxicity by 53% and the freshwater eutrophication potential by up to 97%
I-BIM based approach for geotechnical and numerical modelling of a conventional tunnel excavation
No full textVery recently the Building Information Modeling (BIM) design approach has landed in the infrastructure field, giving life to the I-BIM, the BIM for the infrastructures, including geotechnical underground works likes tunnels. In this framework, the present paper shows an application in the field of geotechnical engineering of the BIM based design approach to the case of an underground line. It is a tunnel excavated by means of traditional method, currently under construction. The project defines, in a central BIM model, a detailed tunnel structure model integrated with geological-geotechnical information for the definition of the subsoil 3D model. Once the BIM model of the tunnel stretch under study was completely defined, it was imported into a finite element (FE) model to perform deformation analyses. Thus, BIM-to-FEM-to-BIM interoperability was exploited in order to verify the maturity level of the BIM approach in the field of application for geotechnical infrastructures. Finally, the BIM fourth dimension (4D) was also implemented in the central model for the time management of the tunnel excavation process, synchronized with the numerical model. The BIM based procedure proposed in the present work can be considered as a case study in the technical literature of I-BIM for tunnels, putting in evidence limitations and advantages: i) a high level of BIM maturity was not yet achieved in the infrastructures field; ii) the BIM-to-FEM interoperability seems to be not fully effective and many operations still require the manual intervention; iii) the FEM-to-BIM interoperability brings back all geotechnical choices and hypothesis to the central BIM model, linking the models into a continuously interoperable circuit; iv) an important part of the design of civil infrastructures consists of addressing geotechnical aspects, hence the inclusion of ground conditions and geotechnical data into the BIM model can improve the quality and the usefulness of the model, not only during the design phase but also, and in particular, during the construction and the lifecycle management of the infrastructure, as a support to decision making process especially in urban context
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