Bitumen Components Research Articles

Materials Contamination and Indoor Air Pollution Caused by Tar Products and Fungicidal Impregnations: Intervention Research in 2014-2019.

Construction materials containing tar products are a source of indoor air pollution in buildings. This particularly concerns old buildings, in which wooden structures were impregnated with tar compositions (creosote oil and Xylamite oil containing tar products) and buildings in which bituminous seal containing hydrocarbon solvents was used. During the 1970s and 1980s, an impregnant known as Xylamite was commonly used in Polish buildings. This material still emits organic vapors into the building’s environment, significantly worsening indoor air quality (IAQ). Xylamites and other impregnating materials are a source of indoor air pollution through toxic organic compounds, such as phenol, cresols, naphthalenes, chlorophenols (CPs), and chloronaphthalenes (CNs), which emit specific odors. TD-GC/MS enables detailed identification of the reasons behind chemical indoor air pollution. The results of laboratory tests on the chemical emissions of bitumen-impregnated materials were presented in 32 case studies. In turn, the results of indoor air pollution by volatile bitumen components were presented on 11 reference rooms and 14 case studies, including residential buildings, office buildings, and others. Laboratory tests of samples of construction products confirmed the main emission sources into indoor air. The research results for the period 2014–2019 are tabulated and described in detail in this manuscript.

Studies of interaction between bitumen and thermochemical fluid (TCF): Insights from experiment and molecular dynamics simulations

Thermal enhanced oil recovery generally involves injection of steam into the reservoir or insitu heat propagation to reduce the viscosity of heavy oil. However, certain shortcomings, which are associated with steam injection, have paved way for finding an alternative method for insitu heat and pressure generation such as thermochemical fluid injection. The thermochemical fluid injection method offers several potential advantages including reduced heat loss, higher heat transfer efficiency, and negligible emission of CO2 compared to conventional steam injection. In this article, a deeper understanding of the process using the molecular dynamics simulations coupled with the experiment are presented. Guided by experimental information obtained from Saturates, Aromatics, Resin and Asphaltene fractions, total acid number, and density of bitumen sample, a molecular model of bitumen was built and validated. Subsequently, supported with the thermodynamic data obtained from the thermochemical reaction vis. enthalpy (ΔH) and order of reaction (n), Molecular dynamics simulations were used to examine the bitumen-thermochemical fluid interface, and the possible molecular interactions that could be involved between the bitumen matrix components and the thermochemical fluid. The thermochemical fluid reaction could generate sufficient temperature, typically, ≈170 °C and pressure ≈1600 Psi. The reaction was first order (n = 1) with ΔH = −370 KJ/mol, and the reaction Ea ≈ 35.5 kJ mol−1. Ultimately, molecular dynamics simulations gave detailed insights into the molecular interactions that could be established at the bitumen-thermochemical fluid interface. Our results put in evidence the changes of bitumen matrix upon the injection of thermochemical fluid. Indeed, molecular dynamics results show that the insitu heat released from the thermochemical reactions induces a homogeneous texture of the bitumen matrix via disturbing the large aggregates of the heavy bitumen components such asphaltene, and resin. The formation of salt resulted in a stronger interaction of salt-acids type between the two phases, which leads to further stabilization of the water-phase inside the bitumen matrix and prevent its collapse. Furthermore, the insitu formation of N2 gas and its diffusion through bitumen matrix softens its texture and lead to disturbing of the tight interaction between the bitumen matrix components. As, the temperature increases the kinetic energy of N2 gas increases and make it more efficient to decrease its viscosity and hence its mobility. This phenomenon has also been corroborated through the thermogravimetric analysis and the scanning electron microscopy, which revealed improved thermal decomposition performance due to reactivity and/or interfacial interactions between thermochemical fluid and bitumen matrix.

Investigation of modified bitumen binders via Fourier-transform infrared spectroscopy

Objectives. This study evaluates the effect of the modification process on the group composition of bitumen and bitumen binders containing rubber powder and hybrid modifier that is based on styrene–butadiene thermoplastic elastomer and rubber crumb. The aim of the study was to determine the presence or absence of functional groups that reflect the direction of physicochemical processes during the preparation of a hybrid modifier in rotary dispersers and during the modification of bitumen binders. Methods. Rubber powder and hybrid modifier were obtained by high-temperature shear grinding using a rotary disperser. Bitumen and modified bitumen binders were investigated via Fouriertransform infrared spectroscopy. Using the method of spectral subtraction, it was determined that during the process of manufacturing modified bitumen binders, structural changes occur in both bitumen and modifiers. During this study, the extraction of modifiers (rubber powder and hybrid modifier) in toluene was performed. Results. The quantitative analysis of changes in the group composition of modifiers before and after the modification procedure was carried out. The active polymer and structural indices were determined. The general trend of the change in the active polymer and structural indices was noted for the initial spectra of the rubber powder and hybrid modifier, and their spectra were obtained after the procedure of subtraction from the spectra of bitumen binders. Conclusions. The interdiffusion of aromatic compounds between the bitumen component and modifier particles was confirmed. On the basis of the results of the extraction of modifiers in toluene, and by taking into account the infrared spectroscopy data, it was determined that during the production of hybrid modifier during the simultaneous grinding of rubber crumb and styrene– butadiene thermoplastic elastomer, there was a chemical interaction between them.

Implication of wax on hindering self-healing processes in bitumen

This paper examines the molecular mechanism of self-healing and hindering effect of wax on self-healing in bituminous adhesives. To do so, computational analysis was combined with microscopy to show the effect of molecular binding and surface morphology on self-healing processes in bituminous adhesives. Specifically, here, we demonstrated how bitumen wax content can hinder self-healing of microcracks in bitumen by promoting formation of characteristic features (bees) on the surface of cracks. Surfaces of a fresh crack in bitumen are free of “bees”, but wax molecules migrate to the bitumen-air interface forming “bee” structures quickly. This can be attributed to “bees” being measurably less adhesive than other bitumen components. This was supported by our computational analysis showing interactions between wax and bitumen components (<22 kcal/mol) are much weaker than interactions among bitumen components themselves (>50 kcal/mol). In addition, the “bees” introduce nanoscale surface roughness that could prevent conformal contact and keep a large proportion of the surfaces separated. This was also evidenced in our density functional analysis showing electrostatic interactions decrease notably with increase of distance between wax crystals. Accordingly, presence of wax can hinder self-healing of bitumen by altering surface morphology and preventing conformal contact between two sides of a microcrack.

Experimental characterization of storage stability of crumb rubber modified bitumen with warm-mix additives

One of the main drawbacks of crumb rubber modified bitumen (CRMB) is the storage stability issue. The storage instability of CRMB impedes its further application. This study aims to develop a robust methodology to evaluate the storage stability of CRMB binders using both mechanical and morphological tests. The effects of rubber contents (0, 5%, 10%, 15%, 22% by weight of bitumen) and different non-foaming warm-mix additives (wax-based and chemical-based additives) on the storage stability of CRMB were investigated. Laboratory tests were also performed on the constituents of CRMB to have a deep understanding of the mechanism of storage instability. Standard tube separation tests were conducted on different binders. Both rheological tests and X-ray computed tomography (CT) scan tests were performed on the binder samples collected from different parts of the tube test. Separation indices were developed based on the difference in mechanical property and rubber content from the tube samples respectively. Results show that CRMB with a higher rubber content is more storage stable than that with a lower rubber content. The addition of warm-mix additives is detrimental to the storage stability of the studied CRMB. Rheological tests were performed on the individual constituents of CRMB (i.e., bitumen phase and rubber phase) to understand better the dynamic asymmetry potentially existing within the unstable CRMB binder. Results show that the residual bitumen becomes stiffer while the swollen rubber becomes softer after interaction because of the preferential absorption of light components of bitumen by rubber. The dynamic asymmetry existing between the bitumen phase and the rubber phase of CRMB results in storage instability. When the bitumen phase has similar dynamic properties as the rubber phase, the resulted binder system will be stable. It is possible to manipulate raw material properties and interaction conditions to achieve the desired crossover between two phases of CRMB and hence obtain a storage-stable CRMB blend.

Effects of microbial degradation on morphology, chemical compositions and microstructures of bitumen

Bitumen is usually suffered from microbial degradation when bituminous pavement is under the shady, humid or polluted environments, leading to the microbial aging of bitumen. To further understand the microbial aging of bitumen, such typical microorganisms on bituminous pavement as bacillus licheniformis (BL), bacillus subtilis (BS) and pseudomonas aeruginosa (PA) were selected to degrade bitumen. Then effects of microbial degradation on morphology, chemical compositions and microstructures of bitumen were discussed. Results indicate that the microorganisms preferentially regard light components in bitumen as nutrient source to propagate on bituminous surface, forming some potholes. Microorganisms further penetrate into the interior of bitumen, resulting in the microbial aging of bitumen. Further, BS and BL have a stronger degradation ability to light components, while PA can degrade more complicated structural components in bitumen. The molecular weight distribution of aged bitumen becomes more concentrated. However, the microbial aging of bitumen does not promote the conversion of unsaturated bond to CO group, and also does not increase the content of SO group. Finally, the microbial aging damages the continuity of bituminous surface elevation, and the whole roughness of aged bituminous surface is lowered. The three microorganisms show the faster aging rates to light components, and are difficult to degrade resins and asphaltenes. BS has a higher prophase activity and a faster aging rate to bitumen than BL at the early stage. The propagating rate of PA is between those of BS and BL, and its prophase activity and aging rate are relatively stable. This study provides an insight into the microbial aging mechanism of bitumen.

Interfacial Activity of Bitumen Components

AbstractThe interfacial activity of asphaltenes, naphthenic acids, and naphthenates has been amply studied in the literature, as they are involved in the formation and stabilization of bitumen and heavy crude oil emulsions. While most of the literature evaluates one component at a time, in this work these bitumen components were separated one at a time from Athabasca bitumen, and the surface activity of the resulting fraction was evaluated as a function of pH, solvent aromaticity (heptane/toluene mixtures, known as heptol, at volume ratios 50/50 and 80/20), and temperature for selected systems. The interfacial activity was evaluated in two ways: via dynamic interfacial tension during adsorption on a bitumen drop of constant volume, and via dynamic interfacial tension during drop volume cycling. The adsorption data were interpreted using a model that combined multicomponent adsorption kinetics inspired by Langmuir–Freundlich kinetics with the Fainerman surface equation of state. The volume cycling experiments were interpreted using the compression relaxation model, which segregates adsorption/relaxation effects from elastic phenomena at interfaces. Overall, the adsorption data confirmed that naphthenic acids are the fastest adsorbing species that tend to dominate the interface, but that asphaltenes adsorb, almost irreversibly, at longer time scales and likely forming a sublayer previously proposed in the literature. The dilatational elasticity of the interface seems to be highly influenced by that asphaltene sublayer, which softens at high pH at room temperature, or at 80 °C independently of the pH of the system.

Aging effects on the composition and thermal properties of styrene-butadiene-styrene (SBS) modified bitumen

The effect of shear rate and mixing time on the composition and thermal properties of unaged and aged bitumen and, SBS modified bitumen was studied using a combination of Fourier Transform Infrared (FTIR) spectroscopy, Modulated Differential Scanning Calorimetry (MDSC) and Thermo-gravimetric Analysis (TGA). The increase in intensity of IR absorbance bands for carbonyl, sulfoxide and aromatic functional groups can be correlated with the oxidation of bitumen as, a consequence of processing, as well as for simulated long-term aging. Modification of bitumen with 5 wt% SBS enhanced the thermal stability of bitumen, altered the mechanism of degradation from a single process to one with three steps and resulted in increases (to 85 °C) in the onset temperature of degradation of aged samples. Irrespective of whether the samples were aged or not, the specific heat capacity (Cp) of the blends, determined from MDSC measurements, increased with increasing shear rate and mixing time, but all Cp values were greater for aged samples. The application of heat and pressure in simulated long-term aging alters the structure of SBS modified bitumen blends via degradation and crosslinking reactions manifest by changes in the glass transition temperature (Tg) of the bitumen components, as measured by MDSC.

Investigation of physicochemical and rheological properties of SARA components separated from bitumen

To further understand the aging and regeneration of bitumen at component level, physicochemical and rheological properties of bituminous components were investigated. Saturates, aromatics, resins and asphaltenes (SARA) from two bitumen were separated. They are subsequently used for purity identification by TLC-FID test. Fluorescence microscopy, infrared spectroscopy and dynamic shear rheometer (DSR) were conducted to characterize the fluorescence effect, molecular structures and rheological properties of SARA components. The results indicate that high purity of components were obtained according to the validation of TLC-FID. Maltenes show fluorescent activity in a decreasing order of aromatics, saturates and resins. Conversely asphaltenes show average 99 vol% gray scale, representing their extreme inertia under ultraviolet light. Aromatics are most susceptible to aging among light components in bitumen due to the detection of carbonyl group in it. It is shown that O–H stretching vibration as the characteristics of alcohol and acid only stay in asphaltenes. Maltenes exhibit typical viscoelastic characteristic, in which aromatics behave most likely to their mother bitumen. They attribute mostly to the flexibility of bitumen. Results of complex viscosity and flow activation energy reveal that saturates and aromatics present better fluidity than their mother bitumen.

Transitions of component, physical, rheological and self-healing properties of petroleum bitumen from the loose bituminous mixture after UV irradiation

In the bituminous mixture, the petroleum bituminous film wrapped in the surface of aggregate is very thin, which is obviously different from the neat bitumen. In this research, the most commonly used dense bituminous mixture (AC-13) was designated for the ultraviolet (UV) irradiation simulation test. The loose bituminous mixture was exposed under the UV irradiation for 7, 14 and 28 days respectively, and the UV irradiation intensity was 21.0 w/m2. After aging, the bitumen was recovered with the centrifuge separation method, the SARA components of the recovered bitumen (RB) was studied by the Thin-layer chromatography with flame ionization detection (TLC-FID). Meanwhile, the physical and rheological performance of the RB was investigated by the three major conventional indices and dynamic shearing parameters. In addition, the self-healing performance of bitumen was characterized by complex viscosity frequency-sweep test, capillary test and surface energy test before and after UV irradiation. The results show that with the extension of UV irradiation time, the chemical components of RB change obviously, which results in the deterioration of its colloid stability. Meanwhile, the physical and rheological performance of RB transitioned significantly (the decreases of penetration, ductility and phase angle of RB, and the increase of the softening point and complex modulus), indicates the RB becomes more embrittlement and hardening. Also, the worse flow behavior, the worse capillary fluidity and the lower surface free energy of RB result in the degradation of the self-healing performance of bituminous concrete.

Phase Behavior of Mixtures of Bitumen andn-Butane

The phase behavior of bitumen and n-butane mixtures was investigated at temperatures from 20 to 230°C and pressures from 2 to 10 MPa. The measurements included saturation pressures, compositions at the onset of the second liquid phase, and the compositions and masses of the light n-butane-rich and heavy “pitch” phases in the liquid-liquid region. The phase compositions were measured in terms of the n-butane, maltenes, and C5-asphaltenes (pentane insolubles) contents. The bitumen component yields were reported as the mass of the component in the pitch phase divided by the mass of bitumen in the feed. The onsets, yields, and phase compositions were insensitive to temperature and pressure except possibly at 2 MPa and 20°C. The phase boundary data were used to construct pressure-composition diagrams. The phase compositions were used to construct a ternary diagram from which equilibrium constants were determined. The equilibrium constants were correlated to the feed n-butane content and used in a flash calcula...

Bitumen Recovery from Crude Bitumen Samples from Halfaya Oilfield by Single and Composite Solvents-Process, Parameters, and Mechanism.

Since 2007, heterogeneous, high-viscosity active bituminous formations have often occurred during the drilling process in Yadavaran oilfield (Iran), Halfaya oilfield (Iraq), and tar sands (Canada). The formation of bitumen exhibits plastic and creep properties, and its adhesion is strong, so drilling accidents are easily caused, such as adhering vibrating screen, drill pipe sticking, lost circulation, and even well abandonment. These complex problems cause huge economic losses. Solvents used to dissolve bitumen are a feasible technology to remove bitumen effectively. In order to solve this problem, we used crude bitumen samples from Halfaya oilfield to study the relation between the bitumen component and different solvents. In this study, the temperature, crude bitumen sample to solvent ratio, stirring rate, stirring time, and ultrasound time on bitumen recovery by toluene were investigated by a single factor experiment. The optimum process parameter for bitumen recovery was obtained. Toluene, n-heptane, tetrahydrofuran, cyclohexane, cyclopentane, ethyl acetate, and n-pentane were chosen as the solvents for single solvent extraction and composite solvent extraction. The bitumen recovery increased significantly with the use of a composite solvent compared to a single solvent. The composite solvent ratio was 1:1. The highest bitumen recovery was 98.9 wt% by toluene/cyclohexane composite solvent. The SARA (saturates, aromatics, resins, and asphaltenes) components of the bitumen were analyzed. The toluene showed the highest asphaltene content, while the n-alkanes showed the lowest asphaltene content. The higher the asphaltene content, the higher the bitumen recovery. The composite solvent obtained the highest asphaltene content and bitumen recovery. The viscosity of bitumen extraction by different solvents was measured. The lower the bitumen viscosity, the higher the bitumen recovery. The element analysis indicated the solvent’s ability to extract bitumen colloids with the C/H ratio. This study provides a reliable theoretical basis for the subsequent adoption of effective anti-bitumen polluted drilling fluid additives.

Correlation of processing parameters and ageing with the phase morphology of styrene-butadiene-styrene block co-polymer modified bitumen

The morphology development of styrene-butadiene-styrene (SBS) block copolymer modified bitumen as a function of processing parameters was investigated using a combination of optical (OM) and confocal laser scanning microscopy (CLSM). The homogeneity of blends of SBS and bitumen increased with increasing mixing time, where the application of higher shear rates enhances the dispersion and distribution of the SBS phase in the bitumen matrix. For higher shear rates, SBS was swollen between 6 and 8 times that of its initial volume and shear rate is more influential than mixing time in achieving a highly dispersed SBS phase in bitumen. The bitumen components having fluorescence properties (i.e. saturates and aromatics) were homogenously dispersed in the bitumen phase, confirmed by highly uniform fluorescence intensity 3D colour maps (CLSM). The fluorescence intensity of the SBS modified bitumen samples was much more variable with regions of high and low intensity due to inhomogeneous dispersion of the polymer in the bitumen and, the absorption of the fluorescence components of the bitumen by the PS and PB phases of SBS. For longer mixing times the SBS modified bitumen aged, observed from a decrease in fluorescence intensity. Long term in-service aging of the SBS modified bitumen blends, simulated using a pressure aging vessel, resulted in a decrease in fluorescence intensity. Only the sample prepared at the lowest shear rate (1000 rpm) and shortest mixing time (15 min) displayed variable intensity in the 3D colour maps as the SBS copolymer was poorly mixed in the bitumen phase.

Oil-in-water emulsification of Athabasca bitumen with pyrrolidine solution

This paper presents an experimental study of use of pyrrolidine solutions to induce the oil-in-water (o/w) emulsion of Athabasca bitumen without using synthetic surfactants. Pyrrolidine, an organic alkali, acts not only as an alkali that generates natural surfactants from acidic oil components in bitumen, but also as a cosolvent that improves the fluidity of the o/w emulsions.Experimental results show that the o/w emulsions created by pyrrolidine solutions can result in a large mobility increase of bitumen because of their low viscosity and high bitumen content. O/w emulsions were observed at low pyrrolidine concentrations (below 20 wt% and as low as 0.5 wt%) and low salinities (0 and 1000 ppm). For example, the sample of 0.5 wt% pyrrolidine in 1000-ppm NaCl brine with 7:3 water-oil-ratio showed a single-phase o/w emulsion at all experimental temperatures from 298 K to 373 K. In comparison to the original bitumen, the o/w emulsion was 4–6 orders of magnitude less viscous at 298 K, 2–3 orders of magnitude less viscous at 323 K, and 1–2 orders of magnitude less viscous at 353 K.The affinity of the organic alkali for asphaltic bitumen is important for o/w emulsification at a wide range of temperatures. Pyrrolidine is superior to the other organic alkalis tested, diethylamine and triethylenetetramine, likely because the cyclic structure makes pyrrolidine more compatible with the asphaltic bitumen. The favorable result with pyrrolidine is also confirmed by the Hansen solubility dispersion parameter.

Molecular dynamics investigation of interfacial adhesion between oxidised bitumen and mineral surfaces

The interfacial adhesion between oxidised bitumen and mineral surfaces at dry and wet conditions was investigated using molecular dynamics (MD) simulations. Molecular models were built for virgin and oxidised bitumen components including saturate, aromatic, resin and asphaltenes. The bitumen models and four representative mineral substrates (namely quartz, calcite, albite and microcline) were employed to construct bitumen-mineral interface systems. These models were validated by the experimental results and MD simulations reported in the literature. The hardening mechanism of the aged bitumen was analysed by comparing the density, cohesive energy density and fraction of free volume between the virgin and oxidised bitumen. Work of adhesion was computed to quantify the adhesive bonding property of the bitumen-mineral interface systems for the virgin, lightly oxidised and heavily oxidised bitumen models under dry and wet conditions. Results show that the oxidised products (carbonyl and sulfoxide) strengthen the intermolecular bonding, resulting in molecular aggregation and physical hardening of the aged bitumen. When bitumen becomes oxidised at the dry condition, the interfacial adhesion of bitumen-acidic minerals (quartz) is dominated by van der Waals interaction which decreases due to the increased bitumen-quartz intermolecular distance caused by the aggregated bitumen molecules during aging. In comparison, the interfacial adhesion of bitumen-strong alkali minerals (albite and microcline) is dominated by electrostatic energy which increases due to higher polarity introduced by the oxidised products. For the bitumen-weak alkali mineral (calcite), the interfacial adhesion is attributed to both electrostatic energy and van der Waals energy, where compared to the virgin bitumen, the electrostatic energy becomes lower for the lightly-oxidised bitumen due to the increased bitumen-mineral distance but becomes higher for the heavily-oxidised bitumen due to higher polarity. At wet condition, water is the dominating factor that affects (weakens) the interfacial adhesion between the bitumen and the acidic minerals (quartz), and the oxidative aging of bitumen is the major factor that affects (strengthens) the interfacial adhesion between the bitumen and the strongly alkaline minerals (albite and microcline). For the weak alkali minerals such as calcite, both water and bitumen aging can significantly affect the interfacial adhesion.

Aging Characteristics of Bitumen from Different Bituminous Pavement Structures in Service.

The aging of bitumen seriously affects the service life of bituminous pavements. At present, there are many related researches on bitumen aging, but most of them focus on aging endured in indoor surroundings and conditions. Therefore, the conclusions obtained cannot reflect the actual aging changes of bitumen in bituminous pavements in service. In order to study the comprehensive aging process and mechanism of bitumen under the influence of service, we studied bridge deck, traffic lane, and ramp with bituminous pavement structures in service. The bitumen samples obtained from the core samples in different bituminous pavement structures were characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), dynamic shear rheometer (DSR), and fluorescence microscope (FM). The aging degree of different bitumen was analyzed, and conclusions were drawn on changes to bitumen aging from different pavement structures. The results showed that the aging degree of bitumen from the upper layer was the most serious, the aging degree of bitumen at the middle layer was weaker than that of bitumen from the upper layer, and the aging degree of bitumen from the bottom layer was the weakest for the different bituminous pavement structures. The aging of bitumen mainly occurred due to oxygen absorption. After aging, viscoelastic components of bitumen changed, and bitumen became harder. The macromolecule of bitumen could be divided into small molecules, and the small molecular weight of bitumen became large. The styrene-butadiene-styrene (SBS) modifier in the modified bitumen became granular after aging, and it appeared as a single phase in bitumen. The aging changes characterized by different analytical methods showed that the aging degree of bitumen from different layers of bituminous pavement structures in service was different. Effective measures should therefore be taken in time to decrease further aging of bitumen from the upper layer of bituminous pavements due to its inevitable early aging in service.

DETERMINING THE EFFECTS OF RH-WMA ON THE ENGINEERING PROPERTIES OF BITUMEN

This study aims to investigate the engineering properties (i.e., physical, chemical, and adhesion properties) of bitumen incorporated with RH-Warm Mix Asphalt (RH-WMA) additive. Base bitumen with a penetration grade of 80/100 was added with 3.0, 3.5, and 4.0% RH-WMA (by total weight of bitumen). The Response Surface Method (RSM) was used to determine the optimum values of the base bitumen and RH-WMA additive which meet the bitumen specification with penetration and softening point chosen as responses in the design layout. Three solutions of 3.04, 3.55 and 3.91% RH-WMA additive that were obtained from the RSM analysis were selected as the optimal values. Results of the physical tests show that adding RH-WMA increases the penetration and ductility values whilst simultaneously reducing the value for the softening point. Analysis of viscosity at various temperatures shows that RH-WMA additive lowers viscosity when the temperature was raised from 100 to 165 °C. The lower viscosity of the modified binders improves their workability. The result of the Fourier Transform Infrared (FTIR) test shows that there is no complex chemical reaction between the base bitumen and the RH-WMA. The surface free energy (SFE) test conducted on the base bitumen and the RH-WMA modified bitumen shows that the total SFE component of the base bitumen increases when higher amounts of RH-WMA was incorporated. The addition of 3.5% RH-WMA results in the highest SFE value of 24.98 mJ/m2. The increase in the total SFE suggests good adhesion between the bitumen and the aggregates.

Design, synthesis and characterization of bitumen emulsifiers based on molecular simulation

Under the guidance of molecular simulation technology, the Monte Carlo molecular mechanics simulation was used to calculate the compatibility of different lipophilic groups with each component of bitumen, and the compatibility of different hydrophilic groups with water. Based on the calculated results of interaction parameters Chi and mixture energy Emix, the preferred structures of lipophilic and hydrophilic groups of bitumen emulsifier were determined. The target bitumen emulsifier was then synthesized by the reaction of organic acid and polyamine. The molecular simulation results showed that the compatibility of lipophilic group T11 with the bitumen was the best, and the mixing ability of the hydrophilic group H5 with water was excellent. The experimental results show that the preferred structures T11H5 had a good emulsifying performance to prepare emulsified bitumen with good storage stability, consistent with the results of the molecular simulation.

The Effect of Resins on Rheological and ageing Characteristics of Bitumen for Pavement

Bitumen consists of thousands of hydrocarbon molecule types with each molecule contributes to the overall bitumen characteristics. Therefore, it is important to identify the influence of each chemical component of bitumen that altogether constructs the bitumen characteristics. This is likely to be completed by evaluating and modifying bitumen components to produce a new type of bitumen with better characteristics. The realistic way to do this is by analysing it in groups or fractions; one group or fraction comprises bitumen molecules with similar characteristics. This paper aims to address this issue by describing the effect of resins on rheological characteristics of bitumen at various ageing process stages. The materials used in this study were Buton rock asphalt or natural rock asphalt from Buton Island in Indonesia which was from Lawele region and petroleum bitumen penetration grade 80/100 from a refinery in Kemaman Malaysia. The materials were tested to identify their charactheristics and the resins components were also extracted and tested with Corbett method. Each extracted resin (from Buton rock asphalt bitumen and petroleum bitumen) was blended in proportions of 0%, 5%, and 10% with the Kemaman petroleum bitumen as a bitumen medium. The blended bitumen samples were also tested for their rheological characteristics using Dynamic Shear Rheometer. Each sample was tested at five different temperature levels (46°C, 52°C, 58°C, 64°C and 70°C) and at un-aged, artificial short-term aged (RTFOT-aged), and artificial long-term aged (PAV-aged) conditions. The results indicated that the source of resins had a significant value of 0.065 or larger than the 0.05 critical point value. There was no difference in the effect of the experiments using either Buton rock asphalt or petroleum bitumen on the complex shear modulus G*. At fresh condition, there was no effect of adding resins on the bitumen rheological characteristics except for the elastic modulus (G’). However, the effect increased over the RTFOT-ageing and PAV-aging level because of the normal ageing process.

Analysis of influence of bitumen composition on the properties represented by empirical and viscosity test

Abstract Bitumen are one of the products in oil processing. The properties of bitumen are influenced by the source of oil itself and by the technological process of oil processing. Most European refineries, of course, are processing for reasons of the resale of petroleum products, especially petroleum suitable for the recovery of light and middle fractions. Therefore, light petroleums are required, with low yields of heavy fractions which are highly economically and in dispositions efficient for processors on the petroleum market. From the perspective of the rafinery the content and the ratio of asphaltenes and maltenes as essential components of bitumen become less important, however, this can significantly impact on future properties of the bituminous binder. The basic tests as penetration and softening point are dedicated to evaluate the bitumen properties and classify the bitumen. These tests are currently insufficient and therefore new test methods and procedures for bitumen characterization are developed. The main theme of the performance-based approach to bitumen binders’ properties assessment is the evaluation of properties from the pavement performance point of view as permanent deformation, fatigue and frost cracking. The evaluation of changes of bitumen properties during the production and paving process of the asphalt mixture is also important. The study is focused on investigating the viscous-temperature behavior and fundamental properties represented by the penetration and the softening point of the samples of paving grade bitumen 50/70 and polymer modified bitumen PMB 45/80-75. The composition of the bitumen was determined by the SARA analysis and organic elemental analysis. The paper points out how the “traditional” tests as softening point, penetration, and viscosity are affected by the composition of bitumen and how the composition of bitumen changes the basic properties of bitumen.