Search results for "BITUME"
showing 10 items of 43 documents
Thermo-rheological analysis of WMA-additive modified binders
2020
AbstractThermo-rheological characteristics of unmodified and modified bitumen have significant impacts on the mechanical response of asphalt. This study investigates the impacts of an organic and a chemical Warm Mix Asphalt additive on bitumen thermo-rheological and mechanical characteristics. Modified binders with different concentrations of each additive were studied and analysed comparatively to a 40/60 penetration grade bitumen. Frequency sweep tests were performed at different ageing levels to characterise the Linear Viscoelastic properties. The multiple stress creep and recovery, linear amplitude sweep (LAS) and low temperature creep stiffness tests, together with the Glover–Rowe (G–R…
Time dependent viscoelastic rheological response of pure, modified and synthetic bituminous binders
2016
Bitumen is a viscoelastic material that exhibits both elastic and viscous components of response and displays both a temperature and time dependent relationship between applied stresses and resultant strains. In addition, as bitumen is responsible for the viscoelastic behaviour of all bituminous materials, it plays a dominant role in defining many of the aspects of asphalt road performance, such as strength and stiffness, permanent deformation and cracking. Although conventional bituminous materials perform satisfactorily in most highway pavement applications, there are situations that require the modification of the binder to enhance the properties of existing asphalt material. The best kn…
Evaluation of the fracture performance of different rubberised bitumens based on the essential work of fracture
2017
The fracture performance of rubberised bitumen in addition to one pre-treated with a Warm Mix Additive (Sasobit®) was investigated using different test methods measuring different damage mechanisms. Two Recycled Tyre Rubber (RTR) modifiers together with two base binders were blended in the laboratory to produce various combinations of Recycled Tyre Rubber Modified Bitumens (RTR-MBs). The first RTR is a standard recycled polymer derived from discarded truck and passenger car tyres by ambient grinding. The second RTR consists of 100% recycled truck tyres derived by cryogenic grinding and pre-treated with special oil and WMA to allow further decrease of asphalt mixture production temperatures.…
Influence of short-term aging on mechanical properties and morphology of polymer-modified bitumen with recycled plastics from waste materials
2020
Polymer-modified bitumen (PMB) is bitumen that has been specifically engineered with polymer for providing enhanced performance in service. The aging of bitumen is a main aspect that is able to affect its final performance: during the production phase in a hot mix plant, all the binders experience short-term aging due to the high processing temperature. The same is true during the production of the modified binder, when the polymer is dispersed at high temperature in the bitumen mass. This paper aims at studying the effect of short-term aging when using different types of modifiers such as recycled polymers obtained from waste materials. A 50/70 penetration-grade bitumen has been modified, …
A simple interpretation of the effect of the polymer type on the properties of PMBs for road paving applications
2018
Abstract The paper presents the results of the rheological characterisation of polymer-modified bitumen for paving applications. In order to find a simple interpretation of the influence of polymer type on the blends produced, in this study high density and low density polyethylene (PE) with different chemical properties were used, as well as ethylene-vinyl acetate. The chemical characteristics of the base bitumen and the polymers used were determined by means of SARA analysis and Fourier Transform Infrared Spectroscopy, FTIR, respectively. The morphology of the produced blends was investigated by means of fluorescent light optic microscopy, while the mechanical properties were investigated…
Improved Testing Setup for Real-Time Monitoring of PMBs During Manufacturing and Rotational Viscosity Measurements
2021
Polymer modified binders (PMBs) are a practical solution to design asphaltmixtures with superior performance. Although these polymers often improve bitumen properties to some extent, their final performance are linked to the accurate control of the properties during manufacturing and storage. However, some of the common procedures used to characterise neat bitumen are not suitable with these binders making their characterisation challenging. This study presents a novel laboratory procedure to produce SBS-MB through a real-time monitoring of the rotational viscosity, as well as an attempt to understand the suitability of current testing geometries to measure viscosity of such a complex bitum…
Experimental study of the pyrolysis of waste bitumen for oil production
2020
Abstract This work focuses on bitumen slow pyrolysis. Mass and energy yields of oil, solid and gas were obtained from pyrolysis experiments using a semi-batch reactor in a nitrogen atmosphere, under three non-isothermal conditions (maximum temperature: 450 °C, 500 °C and 550 °C). The effect of temperature on the product yields was discussed. The gas compositions were analysed using gas chromatography (GC) and the heating value of oil and solid residue was also measured. Using a thermo-gravimetric analyser, kinetic parameters were evaluated through Ozawa-Flynn-Wall (OFW) method. Results showed that oil yield is maximum at 500 °C (50%). Moreover, gas yield increased with increasing pyrolysis …
Effect of additives on the structural organization of asphaltene aggregates in bitumen
2019
Abstract Bitumens are composite materials whose complex organization hinders the rational understanding of their relationships between composition, structure and performances. So, research attempting to shed more light in this field is required. In this work Wide Angle X ray Scattering (WAXS) has been used to explore the influence of six opportunely chosen additives on the bitumen structure with the aim to ultimately correlate the findings with the bitumen performances. Diagnostic fingerprints have been observed in the WAXS profile: asphaltenes form stuck of about 18 A and constituted by about 6 asphaltene units on average. Such stucks are, in turn, organized at higher levels of complexity …
Effect of ageing on the morphology and creep and recovery of polymer-modified bitumens
2018
Polymer additives are used to improve the properties of road bitumens including their oxidative resistance. However, their usage as anti-oxidative materials remains relatively unclear. This study aims to investigate the changes in the morphology and the rheological response of polymer modified bitumens used in road pavement construction caused by ageing. An elastomer (radial styrene butadiene styrene, SBS) and a plastomer (ethyl vinyl acetate, EVA) polymer were mixed with one base bitumen at three polymer concentrations. The bitumens were RTFO and PAV aged. The morphology of the bitumens was captured by fluorescence microscopy while the rheological properties were measured by means of the m…
On the Assessment and Optimisation of the Processing Conditions of Tyre-Rubber Modified Bitumen
2021
The current study aims at understanding the effect of the variables associated with manufacturing rubberised bitumens in order to develop rubberised bitumen with superior mechanical properties and identify optimised processing conditions for its production. The experimental work covered extensive laboratory testing of several rubberised bitumen blends. The rubberised bitumen was manufactured using four paving grade bitumens (180/240, 160/220, 70/100, 80/100), three tyre rubber types (mechanical ground, waterjet powder, ambient ground powder), and various processing conditions (shear levels, temperatures, processing times). Characterisation of the manufactured blends included rotational visc…