Search results for "ASPH"
showing 10 items of 217 documents
Prediction of hydraulic and acoustic properties of open-graded mixes
2014
The use of open-graded mixes increases significantly the hydraulic permeability of pavement and contributes to reduce the noise impact in comparison to traditional pavement. Such characteristics are very appealing and would greatly increase driver's safety. However, during service life, the pores tend to be clogged by many factors among them secondary traffic compaction and filling of voids by fine materials are relevant, especially on heavy routes. In this case the noise reduction and drainage capabilities will gradually disappear, causing serious problems for road safety and maintenance. In this paper we propose a simulation approach in order to predict the drainage and acoustic behavior …
Investigating the Viability of Multi-Recycling of Asphalt Mixtures through a Preliminary Binder Level Characterization
2022
The incorporation of reclaimed asphalt (RA) in hot mix asphalt mixtures is widely considered a sustainable solution for road infrastructure development. Under the scope of the circular economy (CE), the multiple recycling capability of RA has to be assessed in order to ensure its performance at each recycling cycle and also its viability with different additives. The performance of asphalt mixtures with RA strongly depends on the type of rejuvenator, binder, and their degree of blending in the mix. For this reason, it is essential to know the properties of the aged binder extracted from RA to better understand its rheological properties and optimal dosage of rejuvenation to design a satisfa…
Estimation of durability of new surface courses using accelerated load test and expert's opinions
2022
There is an increasing interest among road authorities in studying sustainability assessment of road infrastructure. The durability of the surface course is a critical factor in these calculations and must be carefully considered in the analysis. New types of asphalt mixes with the potential to improve the results in the sustainability assessment have no proven track record and are thus more likely not to be used until solid performance data is available. To bridge the gap and diminish the uncertainty about the durability of Green asphalt mixes for surface courses, a combination of laboratory tests and tests in a circular road simulator were performed. Eight mixes were tested in total, four…
A long-snouted late Eifelian arthrodire from Aragon (Spain)
2021
Carolowilhelmina geognostica Carls, 1995 is a large arthrodire (Placodermi) from the Tortodus kockelianus Conodont Zone, late Eifelian, in the Eastern Iberian Cordillera in southern Aragon. The somewhat incomplete but articulated skull is preserved, showing a long tubular rostral plate, very small postnasal plates, low toothless inferognathals, and a small, slender and flat parasphenoid. Supraorbital and central sensory lines meet their antimeres at the midline of the skull, forming a straight double line. Lines along the ventral surface of the rostral plate probably belong to the suborbital branches of the infraorbital sensory lines. The combination of characters of Carolowilhelmina points…
Exploiting 3D Modelling and Life Cycle Assessment to Improve the Sustainability of Pavement Management
2020
Today road agencies worldwide face difficult decisions for construction, maintenance and rehabilitation of their road infrastructure as they try to balance limited budgets. This is further complicated rising environmental concerns over equipment and techniques used for these practices. This has led agencies to consider alternative approaches for smarter and sustainable pavement asset management systems. This paper considers the use of a low-cost 3D image modelling distress identification and classification proposal for data acquisition and analysis. To establish its environmental friendliness, a case study in Palermo, Italy, is considered wherein a Life Cycle Assessment (LCA) exercise is do…
Bis(oxalato)chromium(III) complexes: Versatile tectons in designing heterometallic coordination compounds
2011
Abstract The mononuclear oxalato-containing chromium(III) complexes of general formula [Cr(AA)(C2O4)2]− (AA = α-diimine type ligand) are able to produce a large variety of heterometallic complexes by acting as ligands towards either fully solvated metal ions or preformed cationic complexes with available coordination sites. This review focuses on the structural diversity of the polynuclear complexes (oligonuclear and coordination polymers) which are generated by the bis(oxalato)chromate(III) species, with a special emphasis to their magnetic properties.
Performance-based characterization of recycled polymer modified asphalt mixture
2021
Due to the introduction of secondary materials, the asphalt mixtures to be designed and tested in our laboratories are constantly becoming much more complex than traditional asphalt mixtures making difficult to use conventional laboratory procedure and/or predict expected results. This study proposes a comprehensive characterization of asphalt mixture modified with recycled polymer compound by using both wet and dry process proposing adjustments to laboratory mixing and sample compaction procedure. Accordingly, three AC20 Hot Asphalt Mixture (HMA) were designed and their conventional and performance related properties were assessed by looking at a) Indirect Tensile test (ITS) a) moisture da…
Towards storage-stable high-content recycled tyre rubber modified bitumen
2018
The addition of crumb rubber particles as bitumen modifier can be currently considered as a well-established alternative to conventional polymers for bitumen modification. However, Recycle Tyre Rubber (RTR) modified binders still present drawbacks such as poor mix workability and hot storage stability. Within this study the authors try unlocking the full potential of devulcanised tyre rubber-heavy oils blend, named Liquid Rubber (LR), by exploring the possibility of tailoring recycled polymer modified bitumen with unconventional high-content of RTR and designed to overcome the above mentioned technological problems of RTR modified bitumen while keeping its advantages. Results show that LR-b…
An investigation on using pre-treated tyre rubber as a replacement of synthetic polymers for bitumen modification
2015
Rubberized bitumen obtained through a swelling process, has widely proven to be a successful technology for asphalt pavement applications and a solution to reduce the dismantling of tyre rubber on landfills. However, this technology presents two main operative issues which needs the adoption of costly special equipment. Firstly, significant high value of High Temperature Viscosity (HTV) which imposes mixing and compaction difficulties and leads to increased energy consumption and emissions. Furthermore, during the hot storage period, phase separation between rubber particles and the base bitumen could occur. Developing Recycled Tyre Rubber Modified Bitumen (RTR-MBs) with improved storage st…
Linear ViscoElastic (LVE) Behaviour of Pure Bitumen via Fractional Model
2012
AbstractBy fitting experimental data from static creep/recovery carried out on pure bitumen, it is shown that the fractional model proposed enables the description of both creep and recovery behaviour with fewer parameters than those needed by other models in the literature. In particular, the model is fitted to experimental data of complex modulus |G*| and phase angle δ° obtained from Dynamic Mechanical Analysis. Lastly, it is demonstrated that when the fractional model is used, complex modulus isotherms for a range of frequencies can be created simply starting from isochronals at f = 1Hz.