The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Feng Wei - One of the best experts on this subject based on the ideXlab platform.
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simultaneous removal of asphaltenes and water from water in Bitumen Emulsion i fundamental development
Fuel Processing Technology, 2008Co-Authors: Yingxian Zhao, Feng WeiAbstract:Abstract Simultaneous removal of asphaltenes and water from a water-in-Bitumen Emulsion by adding light paraffinic solvents was investigated with a bench-scale unit. Asphaltene precipitation in Bitumen, Emulsion breaking, and phase separation were found to be largely dependent on solvency and temperature. Increasing temperature facilitated the precipitation of asphaltenes in Bitumen, and accelerated the separation of the light deasphalting oil (DAO)/solvent phase and the heavy asphaltenes/water phase. The removal of 98 +% asphaltenes and 99.9 +% water from the Emulsion was achieved with the n -pentane/Bitumen volumetric ratio of 3.0 in temperature range of 423–453 K. The interaction between asphaltene particles and water droplets is actually beneficial to the removal process. For process design and optimization, the operation pathway including two-step solvent injections at different temperature, the supercritical recovery of solvent from DAO stream and the solidification of asphaltenes by depressurization, as well as other important issues have been addressed.
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simultaneous removal of asphaltenes and water from water in Bitumen Emulsion ii application feasibility
Fuel Processing Technology, 2008Co-Authors: Yingxian Zhao, Feng WeiAbstract:Abstract Application feasibility of the accelerated deasphaltening process for simultaneous removal of asphaltenes and water from a water-in-Bitumen Emulsion has been examined with a pilot plant having capacity of 1.590 m3/day. The solvent (n-pentane) was injected into the Emulsion from three locations with progressively increasing temperature from 423 K. The first solvent injection precipitated the asphaltenes in Bitumen, the second broke the Emulsion and facilitated the phase separation, and the third extracted the oil that remained in heavy asphaltenes/water phase. The effects of operation parameters such as temperature, solvent/Bitumen ratio, feed rate and feedstock composition on the quality of DAO (Deasphaltening oil) were investigated. The DAO with the yield of ~ 80 wt.% and asphaltene content of
Pietro Lura - One of the best experts on this subject based on the ideXlab platform.
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mechanical behaviour of Bitumen Emulsion cement composites across the structural transition of the co binder system
Construction and Building Materials, 2019Co-Authors: Miomir Miljkovic, Lily D Poulikakos, Fabio Piemontese, Mahdieh Shakoorioskooie, Pietro LuraAbstract:Abstract The aim of this research was to understand the dependence of the mechanical behaviour of Bitumen Emulsion-cement composites on the structural transition of the co-binder system. The experimental programme mainly consisted of cyclic indirect tensile testing at a range of temperatures and frequencies, integrated by X-ray microtomography. The results showed the existence of a critical composition of the co-binder system at the Bitumen to cement ratio between 1 and 2 at which the mechanical behaviour transformed from cement-dominated to Bitumen-dominated. This was caused by both the percolation of the bituminous phase and the pore space, and the volume contraction of the co-binder system. However, this critical composition did not directly match with the percolation of the phases on the length scale of the mesostructure, but likely corresponded with the volumetric content of all elastic phases, with the aggregate playing a fundamental role.
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influence of emulsifier content on cement hydration and mechanical performance of Bitumen Emulsion mortar
Materials and Structures, 2017Co-Authors: Miomir Miljkovic, Pietro Lura, Xing Fang, Martin RadenbergAbstract:The objective of this research was to investigate the influence of a cationic emulsifier on the kinetics of cement hydration and on the overall mechanical performance of Bitumen Emulsion mortar, as an essential structural component of cold asphalt mixtures, within a 28-day curing period. This influence was investigated as a function of emulsifier content and Bitumen grade, selected to cover the whole range of their applicability. The hydration kinetics was evaluated by heat release of cement pastes and Bitumen Emulsion mortars. The residual w/c was determined at characteristic points during curing. The emulsifier showed a very powerful effect on the complex relation between hydration kinetics, Emulsion rheology, and water binding. The presence of the Emulsion initially accelerated the hydration, with no main peaks and dormant period observed, but had almost no effect on the ultimate hydration degree. The rate of hydration during the rest of the curing period was critically dependent on the residual w/c which was decisively influenced by the content of emulsifier. The cement could be expected to reach a very high degree of hydration only in mixtures with the highest emulsifier content, considering the specimens as a whole. Together with Emulsion breaking at early stage, cement hydration later on was directly reflected on indirect tensile properties of the mortars, which performed from very ductile to very brittle. In conclusion, the emulsifier was recognised as a key factor for a fundamental understanding of the mechanical performance of cold asphalt mixtures.
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overview on cold cement Bitumen Emulsion asphalt
RILEM Technical Letters, 2016Co-Authors: Xing Fang, Alvaro Garciahernandez, Pietro LuraAbstract:Cold mix asphalt, a promising substitute for conventional hot mix asphalt, is manufactured at ambient temperature using Bitumen Emulsion as binder. To improve its strength and durability, cement is often added to the mixture. This review (1) presents an overview about advances in cold mix asphalt modified with cementitious materials, often called CBEA (cement Bitumen Emulsion asphalt), (2) illustrates advantages and disadvantages of CBEA and (3) gives recommendations to produce homogenous CBEA mixtures
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Influence of Cement on Rheology and Stability of Rosin Emulsified Anionic Bitumen Emulsion
Journal of Materials in Civil Engineering, 2016Co-Authors: Xing Fang, Alvaro Garcia-hernandez, Frank Winnefeld, Pietro LuraAbstract:AbstractOrdinary portland cement (OPC) has been extensively used in cold recycling asphalt and cold-mix asphalt as an additive in order to improve the early age performances of these mixtures. The main purpose of its application is that cement hydration benefits the strength development by consuming water and by accelerating the Bitumen Emulsion breaking. The aim of this study is to investigate the influence of cement on the rheology and stability of rosin-emulsified anionic Bitumen Emulsions. With this purpose, an anionic Bitumen Emulsion blended with various amounts of cement and limestone filler was studied by means of a Brookfield viscometer. Optical microscopy was used to investigate the breaking process of the Bitumen Emulsion and the morphology of Bitumen droplets in the presence of cement and filler. In addition, the stability of anionic Bitumen Emulsions was studied in dependence of the pH and the calcium ion concentration. The results indicate that, unlike limestone filler, which has no signific...
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impact of rapid hardening cements on mechanical properties of cement Bitumen Emulsion asphalt
Materials and Structures, 2016Co-Authors: Pietro Lura, Xing Fang, Frank Winnefeld, Manfred N. Partl, Alvaro GarciaAbstract:Cement Bitumen Emulsion asphalt (CBEA) is obtained by mixing Bitumen Emulsion, cement, aggregates and filler at ambient temperature. CBEA is thought to be a promising substitute for hot mix asphalt because of its low environmental impact and cost-effectiveness. Disadvantages of this material are the long time required to reach its full strength and the inadequate understanding of the hardening mechanisms. This study aims at accelerating the development of mechanical properties of CBEA by using rapid-hardening cements while at the same time gaining a deeper understanding of the role of cement in CBEA. With this purpose, cold mix asphalt mixtures with cationic and anionic Emulsions and different types of cement (ordinary Portland, calcium sulfoaluminate and calcium aluminate cement) were studied by means of isothermal calorimetry, measurements of water evaporation and Marshall tests. The results indicate that both anionic and cationic Bitumen Emulsions may affect the initial hydration rates of the cements used but have no significant influence on their degree of hydration after a few days. The addition of calcium sulfoaluminate and calcium aluminate cement to CBEA leads to mechanical properties after 1-day curing similar to those obtained with Portland cement after 1-week curing. Cement hydration dominates the strength gain, especially for rapid-hardening cements, and the type of cement influences both the amount of bound water and the rate of water evaporation from the CBEA.
Ignacio Pérez Pérez - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation of Bitumen Emulsion stabilised base course mixtures with c d waste aggregates considering nonlinear elastic behaviour
Construction and Building Materials, 2020Co-Authors: Ignacio Pérez Pérez, Luis Medina, Breixo Gomezmeijide, Pedro Alves Costa, Antonio CardosoAbstract:Abstract This study presents the numerical modelling of a load-volume road pavement section with Bitumen Emulsion-stabilised base courses. The base courses used natural and construction and demolition aggregates. A 3D finite difference model was used to determine the peak responses of the pavement sections when subjected to loads. Three nonlinear models were adopted in the two base courses. The response predictions of the three models were similar. Both the resilient and permanent behaviours of these materials were modelled. An analysis was conducted on the rutting resistance of the base course materials. Both base courses were suitable for use in low-volume roads. The base course made with construction and demolition aggregates was more resistant to rutting.
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Nonlinear elasto-plastic performance prediction of materials stabilized with Bitumen Emulsion in rural road pavements
Advances in Engineering Software, 2015Co-Authors: Ignacio Pérez Pérez, Luis Medina, Miguel A. Del ValAbstract:It was used a numerical code to study the response of Bitumen Stabilized MaterialsA nonlinear elasto-plastic Mohr-Coulomb model was used in BSMBoth the resilient and permanent behaviour of BSM were mode lledThe BSM material containing 1% cement is more resistantBSM fail first due to rutting before fatigue. This article presents numerical modelling of rural road pavement sections recycled in situ with two materials stabilized with Bitumen Emulsion. The two materials stabilized with Bitumen Emulsion are base course materials comprising 25% reclaimed asphalt pavement and 75% natural aggregates with and without 1% cement. A 3D-finite difference model was used to determine the response of these pavement sections when subjected to two types of loads with four types of soil subgrades of varying resistances. A nonlinear elasto-plastic Mohr-Coulomb model was used in the two materials stabilized with Bitumen Emulsion, and a nonlinear model was adopted in the four soil subgrades. Both the resilient and permanent behaviours of these materials were modelled. An analysis was conducted on rutting and fatigue resistances of the base course materials. The base course material containing 1% cement is more resistant and is apt for use in lightly trafficked rural roads. Both base course materials stabilized with Bitumen Emulsion will first fail from rutting before fatigue.
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mechanical properties of hot mix asphalt made with recycled concrete aggregates coated with Bitumen Emulsion
Construction and Building Materials, 2014Co-Authors: A R Pasandi, Ignacio Pérez PérezAbstract:Abstract The incorporation of recycled concrete aggregates (RCA) in hot-mix asphalt (HMA) could be a way to promote sustainable construction. To date, several investigations have examined the use of this type of waste material in HMA. Several researchers have observed that due to the action of water, the use of this material proved to have insufficient durability. In this investigation, a laboratory characterisation of HMA made with RCA from construction and demolition waste (CDW) for base layers in road pavements was conducted. Percentages of 5%, 10%, 20% and 30% of RCA in place of natural aggregates were analysed. To improve the water resistance of the mixes, the RCA were coated with 5% of Bitumen Emulsion prior to the mixing process. The results indicated that the mixes comply with the Spanish water resistance specifications required for base layers. The stiffness, permanent deformation and fatigue of the mixtures were also studied. The results indicated that HMA made with RCA coated with Bitumen Emulsion exhibited mechanical properties similar to those obtained for conventional mixtures.
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Mechanical properties and behaviour of in situ materials which are stabilised with Bitumen Emulsion
Road Materials and Pavement Design, 2013Co-Authors: Ignacio Pérez Pérez, Luis Medina, Miguel A. Del ValAbstract:This article presents a critical review of the mechanical properties of in situ materials which are stabilised with Bitumen Emulsion. A description is provided of the types of materials that are stabilised with Bitumen Emulsion presently available and different hypotheses about their behaviour and different properties are put forth. The two main categories of mechanical properties investigated in the laboratory by means of mechanical test are addressed: (a) properties similar to those of granular materials in accordance with their stress-dependent behaviour and (b) properties resembling hot mix asphalt materials in accordance with their temperature and time-dependent viscoelastic behaviour. The article concludes with several final remarks on the structural behaviour and mechanical properties of these materials.
Yingxian Zhao - One of the best experts on this subject based on the ideXlab platform.
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simultaneous removal of asphaltenes and water from water in Bitumen Emulsion i fundamental development
Fuel Processing Technology, 2008Co-Authors: Yingxian Zhao, Feng WeiAbstract:Abstract Simultaneous removal of asphaltenes and water from a water-in-Bitumen Emulsion by adding light paraffinic solvents was investigated with a bench-scale unit. Asphaltene precipitation in Bitumen, Emulsion breaking, and phase separation were found to be largely dependent on solvency and temperature. Increasing temperature facilitated the precipitation of asphaltenes in Bitumen, and accelerated the separation of the light deasphalting oil (DAO)/solvent phase and the heavy asphaltenes/water phase. The removal of 98 +% asphaltenes and 99.9 +% water from the Emulsion was achieved with the n -pentane/Bitumen volumetric ratio of 3.0 in temperature range of 423–453 K. The interaction between asphaltene particles and water droplets is actually beneficial to the removal process. For process design and optimization, the operation pathway including two-step solvent injections at different temperature, the supercritical recovery of solvent from DAO stream and the solidification of asphaltenes by depressurization, as well as other important issues have been addressed.
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simultaneous removal of asphaltenes and water from water in Bitumen Emulsion ii application feasibility
Fuel Processing Technology, 2008Co-Authors: Yingxian Zhao, Feng WeiAbstract:Abstract Application feasibility of the accelerated deasphaltening process for simultaneous removal of asphaltenes and water from a water-in-Bitumen Emulsion has been examined with a pilot plant having capacity of 1.590 m3/day. The solvent (n-pentane) was injected into the Emulsion from three locations with progressively increasing temperature from 423 K. The first solvent injection precipitated the asphaltenes in Bitumen, the second broke the Emulsion and facilitated the phase separation, and the third extracted the oil that remained in heavy asphaltenes/water phase. The effects of operation parameters such as temperature, solvent/Bitumen ratio, feed rate and feedstock composition on the quality of DAO (Deasphaltening oil) were investigated. The DAO with the yield of ~ 80 wt.% and asphaltene content of
Yua Zhang - One of the best experts on this subject based on the ideXlab platform.
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preparation and characterization of waterborne epoxy modified Bitumen Emulsion as a potential high performance cold binder
Journal of Cleaner Production, 2019Co-Authors: Zhe Leng, Yua ZhangAbstract:Abstract This study aims to explore the feasibility of using waterborne epoxy modified Bitumen Emulsion (WEB) as a high-performance cold binder through chemical analysis and performance characterization. To achieve this objective, waterborne curing agent was first synthesized and characterized by Fourier transform-infrared spectroscopy (FT-IR) and Zetasizer. Then, FT-IR analysis was conducted to monitor the curing behaviour of epoxy resin in Bitumen Emulsion. Following the moisture susceptibility tests of Bitumen Emulsion mixture through the boiling tests, the rheological properties of WEB residues were characterized through the dynamic shear rheometer (DSR) tests. Finally, linear amplitude sweep (LAS) analysis was conducted to evaluate the fatigue resistance of the Bitumen Emulsion residues. The results indicated that the incorporation of waterborne epoxy resin into Bitumen Emulsion significantly improved its adhesion performance, mechanical strength, and fatigue life, making WEB a potential high-performance cold binder for various application purposes, such as cold recycling and cold-mix asphalt paving.
