Search results for "ASPH"
showing 10 items of 217 documents
Rheological investigation on the ageing performance of bio-recycled asphalt binders and mixtures
2023
The current need to move towards more sustainable technologies in the construction sector has promoted the investigation of using alternative materials in asphalt mixtures for pavements. Biomaterials, used as biobinders, have shown their potential as partial replacement of bitumen in asphalt mixtures as solution to decreasing the demand for fossil-fuel-based binders as well as CO2 emissions. However, more research is needed to increase the replacement of bitumen in asphalt mixtures. In this investigation,biobinders are used as full replacement of virgin bitumen and as recycling agent within asphalt mixtures with high Reclaimed Asphalt (RA) content. Blends of biobinders and RA binders, and b…
An italian research on mechanical properties on asphalt with tire-rubber
2003
In Palermo a research study was initiated with following objectives: characterisation of the asphalt with tire rubber; study of pavements overlaid with this type of asphalt; cost estimation of asphalt rubber production process. This paper describes the first results achieved in the study concerning the mechanical properties of asphalt with tire rubber for road base and base course. In this research on dry process, more than 400 specimens have been tested at the DIIV laboratory for analysing the influences of crumb rubber modifier and powdered rubber modifier on the Marshall and indirect tensile test.
EXPERIMENTAL INVESTIGATION ON DRY ASPHALT RUBBER FOR SUBBALLAST
2011
The asphalt rubber mixes have a wide application field in the railroad and road superstructures because of their technical and environmental properties. While in many countries the wet process is often used to make bituminous mixtures, the dry process doesn’t have the same degree of application even though a larger recycling of waste tires rubber is allowed than the dry process. This paper focuses on the mix-design of the Dry Asphalt Rubber (DAR) for subballast of the railroad superstructure in order to define a sound laboratory procedure of mix-design with reference to Marshall test and Superpave Gyratory Compactor (SGC) test. The comparison between Marshall test and SGC test highlights th…
Experimental characterization of asphalt for an elasto-visco-plastic constitutive model.
2007
This paper describes a range of uniaxial creep tests that have been undertaken for a proprietary polymer modified asphalt, the procedure used to determine the parameters required for an elasto-visco-plastic constitutive model. Uniaxial compressive creep testing and creep recovery testing have been undertaken over a range of temperatures and stress conditions. Procedures used to determine the model parameters from the test data are detailed and parametric equations are developed to describe the model parameters as functions of the test conditions. Particular attention is given to the determination of the parameters related to visco-plastic flow and damage accumulation at high strain levels. …
Rubberised stone mastic asphalt mixtures: a performance-related evaluation
2022
The binder content of rubberised asphalt mixtures is usually increased compared to that used in conventional asphalt. This increase is deemed important to compensate for the reduction in the actual bitumen due to the existence of rubber particles. This study presents the results of performance evaluation conducted on different rubberised Stone Mastic Asphalt (SMA) mixtures produced using different types and contents of rubberised bitumen. The energy ratio (ER) computed from Superpave Indirect Tensile (IDT) tests was used to evaluate the cracking resistance of asphalt mixtures while the rutting behaviour was evaluated using the Repeated Load Axial Test (RLAT). The indirect tensile stiffness …
Sustainable Materials Containing Biochar Particles: A Review
2023
The conversion of polymer waste, food waste, and biomasses through thermochemical decomposition to fuels, syngas, and solid phase, named char/biochar particles, gives a second life to these waste materials, and this process has been widely investigated in the last two decades. The main thermochemical decomposition processes that have been explored are slow, fast, and flash pyrolysis, torrefaction, gasification, and hydrothermal liquefaction, which produce char/biochar particles that differ in their chemical and physical properties, i.e., their carbon-content, CHNOS compositions, porosity, and adsorption ability. Currently, the main proposed applications of the char/biochar particles are in …
Joziknipholones A and B: The First Dimeric Phenylanthraquinones, from the Roots ofBulbine frutescens
2007
From the roots of the African plant Bulbine frutescens (Asphodelaceae), two unprecedented novel dimeric phenylanthraquinones, named joziknipholones A and B, possessing axial and centrochirality, were isolated, together with six known compounds. Structural elucidation of the new metabolites was achieved by spectroscopic and chiroptical methods, by reductive cleavage of the central bond between the monomeric phenylanthraquinone and -anthrone portions with sodium dithionite, and by quantum chemical CD calculations. Based on the recently revised absolute axial configuration of the parent phenylanthraquinones, knipholone and knipholone anthrone, the new dimers were attributed to possess the P-co…
Environmental sustainability and energy assessment of bituminous pavements made with unconventional materials
2019
The increasing sensibility towards the questions related to climate change has made the scientists and technicians aware of the need to incorporate the principles of sustainable development into the road construction sector. In this view, recycled materials in road pavements and technologies to decrease the overall carbon footprint have become more and more important. Based on the ISO14040 series, the overall purpose of this study is calculating, by means of a systemic approach, the life-cycle energy and the carbon footprint of road pavement solutions. To this aim, several alternatives in terms of bituminous mixtures (warm mix asphalt, reclaimed asphalt pavements, waste plastics) were consi…
Polythiophenes as markers of asphalt and archaeological tar pitch aging. Characterization using solid-state electrochemistry
2018
The voltammetry of immobilized microparticles (VIMP) was used to characterize organosulfur components from ovens found at the Spanish archaeological sites of Cueva de Nerja (ca. 35,000cal BC), la Illeta dels Banyets (4th century BCE) and Gestalgar (12th–13th CE), and asphalt probes subjected to PAV and SUNTEST aging protocols. The voltammetric responses of the archaeological samples and the asphalt probes after photodegradation were quite similar, indicating the presence of polythiophene components which could act as age/degradation markers. Keywords: Voltammetry, Archaeology, Asphalt, Tar pitch, Organosulfur compounds
CHARACTERIZATION OF RUBBERIZED ASPHALT FOR RAILWAYS
2018
Rubberized asphalt mixtures are regarded as a solution for improving the strength of the rail-track section. The recycled rubber has become an enhancer of the modified bituminous mixtures. In this work, it has been shown as a sustainable improvement option in HMA mixes due to the elastic behavior exposed by the rubber particles. The impact of thermal susceptibility on the mechanical properties of the railway bituminous sub-ballast layer has served to the advanced measurement of the thermal cycles inside the rail track. Different simulations following the Kentrack and Kenpave software were employed to be effective with the best mix-design for railways. According to weather situation, reviewe…