177,811 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
A Practice for the Application of Waste in Road Asphalt Pavements in an Eco-Friendly Way
No full textThe integration of circular economy principles in the design of road pavements raises the problem of obtaining high-performance asphalt mixtures for reduction of waste and environmental pollution compared to traditional solutions. In this study, the base and binder layers of road asphalt pavements were prepared by using reclaimed asphalt pavement and construction and demolition waste as coarse aggregates, while jet grouting waste and fly ash served as fillers. A leaching test was performed for the marginal materials, after which the engineering performances of the designed asphalt mixtures were investigated through laboratory tests. A life cycle assessment methodology was applied to determine the life cycle impacts of one cubic meter of each asphalt solution. Next, a multi-criteria decision analysis (MCDA) was performed for the solutions suggested for the binder and base layers. Finally, a sensitivity analysis was conducted to identify the most suitable MCDA solutions by varying the weights for a total of 24 different weight configurations. The results of this work revealed that the solutions utilizing jet grouting waste (in particular, the hot asphalt mixture for the binder layer and cold asphalt mixture for the base layer) were preferred to other traditional and alternative solutions in most decision-making scenarios
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
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Surface monitoring of road pavements using mobile crowdsensing technology
No full textPavement-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
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