1,720,972 research outputs found
Effectiveness of slab stabilization in mitigating reflective cracking in HMA overlays: a case-history
No full textSlab stabilization is the pressure insertion of a flowable material beneath a concrete slab, in order to restore slab support. The application of such a technique can pose some problems. Therefore, an experimental study has been performed on the start of the runway (turnaround bay) of an Italian airport in order to assess the real capability of different types of slab stabilization techniques to rehabilitate the needed bearing properties. Crack surveys, deflection tests by the FWD and traditional plate bearing tests on the subgrade have been performed prior and after the four types of interventions in order to evaluate the structural effects at the centre, at joints and corners of slabs. The obtained results are useful in assessing the different capability of such rehabilitation strategies to optimise bearing properties and allow to identify the effect in mitigating reflective cracking in asphalt overla
Tire-road noise on different road pavements: synergetic influence of acoustical absorbing coefficient and surface texture
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SIMULAZIONE DEL DECADIMENTO DELLE PROPRIETA’ SUPERFICIALI DI STRATI D’USURA IN CONGLOMERATO BITUMINOSO
No full textAngolarità dell'aggregato fino e prestazioni meccaniche dei conglomerati bituminosi:Indagine sperimentale
No full textTime-dependent surface properties of asphalt friction courses: earlier experiments by a new accelerated test
No full textStructural health monitoring of pavement assets through acoustic signature
No full textThe assessment of the structural and functional pavement condition is nowadays fully machine based and non-destructive equipment does cover all the data input required for a modern PMS approach. A Multi-Laser Vehicle is capable of real time continuous traffic-speed measurements of condition data regarding cracking, ravelling, rutting, roughness, macro texture and road geometrics in a single run using high-speed line-scan cameras for an automated assessment. The system of the Multi-Laser Vehicle equipped with a Laser Crack Measuring System (LCMS) is the most promising development in 3D camera technology with a progressive improvement of capabilities and quality. This paper discusses the results of the equipment used as well as the accuracy and repeatability achieved. Shown is as well the continuous measured macro texture based on the Mean Texture Depth (MTD) as index using the LCMS device in addition to the automated crack detection. A major advantage is that no conversion is required as the volumetric MTD is a direct output. The LCMS based automated MTD analysis is a machine based result not influenced by a human factor such as the Sand Patch. The results allow as well the automated analysis of loss of aggregate which is a major advantage in rating the severity and extent of ravelling in comparison to the non-consistent wind-screen surveys and manual rating of collected images. In addition to the MTD the sampling of rutting has been validated against the multi-laser profiler approach as well as the International Roughness Index (IRI) based on Inertial Motion Units (IMU’s) attached to the LCMS sensors
ON THE SUSTAINABILITY OF NOISE MITIGATION MEASURES
No full textIn recent years, the issue of sustainability has assumed great importance in every field, including noise mitigation measures, and interested stakeholders have found themselves struggling with still evolving and uncertain techniques to evaluate the related social, economic, and environmental aspects. Indeed, the sustainability assessment can be accomplished with many different methods and countless indicators. To clarify the problem and identify suitable methodologies to assess the sustainability of noise mitigation solutions for roads, the Italian PIARC committee TC 3.4.2 has undertaken an in-depth study on the most ascertained techniques, from Life Cycle Sustainability Assessment to the more recent Envision protocol. This study has involved a broad and focused effort to define the meaning of sustainability, from the perspective of infrastructure managers, users, and the general population. Criteria and indicators to describe the performance of noise mitigation solutions have been identified and a general procedure for assessing the sustainability of noise mitigation measures has been defined. The selected method and indicators have then been applied to a case study, located in a suburban environment, to test their applicability and reliability. In this paper, the main outcomes of this study are reported
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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