Rheological Properties Of Asphalt Research Articles

The Copolymers and their Effect on the Rheological Properties of Sulfureted Asphalt

Due to the harsh climatic conditions and the maximum loads on the original unmodified asphalt used in paving process, some defects appear over time such as cracks and deformation of roads. This calls for work to improve the rheological properties of asphalt to produce asphalt paving more resistant to the factors above. This study focuses on the use of polymeric mixtures of consumed copolymers in asphalt modification processes. These polymers were thermally treated to find out the temperature at which they could be used in the modification process. Asphalt was treated with different percentages of sulfur as a catalyst under specific conditions of temperature and reaction time, during which the optimum catalyst ratio that can be used in the modification processes was determined. Asphalt was treated with a polymer mixture consisting of (ASA and SBS) (1:1) in different weight ratios with the presence of the optimum catalyst ratio and under the above reaction conditions. Several samples were obtained and the rheological properties of the original and modified asphalt were measured by penetration, softening point, ductility and penetration index calculation as well as calculating the weight percentage of asphaltene. The best sample obtained from the above modification process was determined, and reactions were performed on it again to determine the optimal temperature and reaction time, as well as to determine the optimal percentage of sulfur as a catalyst by measuring the rheological properties of the best sample. The best sample obtained in this study was (AS9), and to find out the suitability of this sample that was selected for paving process, the Marshall, chemical immersion and aging test as well as the field emission scanning electron microscope were performed. The modified sample gave better rheological properties and a resistance greater by 56% than the original asphalt when compared with the standard specifications approved in the field of paving.

Effect of ATH/EG Composite Flame Retardant on Properties of High Viscosity Asphalt

In order to improve the flame retardant property of asphalt, ATH (aluminum hydroxide)/EG (expandable graphite) composite flame retardant was obtained by hydrothermal method. The flame retardancy of asphalt was analyzed by oxygen index test. The rheological properties of asphalt were analyzed by dynamic shear rheological test and bending beam rheological test. The research results show that the optimal mix ratio of the compound flame retardant with the best flame retardant synergistic effect is ATH:EG = 1:1. Considering the flame retardancy and rheological properties, the content of ATH/EG composite flame retardant is recommended to be 15%~20%.

Modifying The Rheological Properties Of Asphalt Using Waste Additives and Air Blowing and Studying The Effect Of Time Aging On The Modified Samples

The modification of asphaltic materials with polymeric materials and other additives is one of the most important processes or modifications that take place on asphalt materials. The purpose of these modified that take place is the main purpose of which is to obtain asphaltic materials with a good specifications for the purposes for which it is used, whether that use is in the field of paving, flattening or as a mastic. This study included the treatment of asphaltic materials with modified materials represented by polyvinyl chloride and spent lubricating oils. The asphalt was treated with these additives in different percentages and in the presence of sulfur again and again in the presence of sulfur with anhydrous ferric chloride as acatalyst at a temperature of 150 ° C. An air blowing process was used on both paths. The rheological properties of the original asphalt and the modified and original samples were measured (penetration, softining point and ductility In addition, penetration index was calculated) for all samples After that, the samples were left for the aging factors for a period of 12 months. The rheological properties were measured again. This study gave a good samples when compared to standard samples.

Studying the effect of using a mixture (synthetic polymer: natural polymer) on the rheological properties of asphalt

The rheological modification of asphalt is currently the most important concern of workers in this field, whether a person is a chemist or a civil engineering worker. Several methods are used in rheological modulation processes. The rheological modification with polymeric materials is still the one that has taken the largest space in this field In this study, we dealt with the rheological modulation processes with polymeric mixtures. It used a mixture of materials that have proven effective in the field of rheological modulation and others that did not give the desired results. In this study, a mixture of a synthetic polymer, which is ethylpene vinyl acetate, and a natural polymer, which is wood, were used. Use this mixture with different weights of both polymers and for a total of 1 gram. The asphalt was treated with the above mixture with 1% by weight of sulfur at 180 ° C for a period of one hour The rheological properties of the modified samples were measured, which included measuring the ductility, penetration and softining point as well as calculating the penetration index coefficient and the percentage of the separated asphaltens.After that, the best sample obtained from the above treatment was taken and several interactions were conducted on it in order to determine each of: The optimum percentage of sulfur, The optimum temperature for modification process, The optimal time to perform the rheological modification processes, The effect of the addition process sequences on the properties of the axis asphalt was also studied. After that, the best sample obtained from this study was taken and was measured (Marshal, chemical immersion and as well as studying the effect of aging on this sample). The study gives good results in the field of asphalt resistance to the deformation processes that were carried out on it.

Evaluation of VOCs inhibited effects and rheological properties of asphalt with high-content waste rubber powder

Waste rubber powder (WRP) has become a widely used and sustainable replacement for asphalt modifier. At present, the mixing content of WRP in waste rubber modified asphalt (WRMA) is basically between 18 and 22%, while the high-content (25–45%) WRP modified asphalt (HC-WRMA) can realize the high added value utilization of solid waste and show excellent high temperature properties at the same time. However, more volatile organic compounds (VOCs) will be generated with the increase of the content of WRP, which would lead to environment pollution. This research aimed to explore the optimal mixing content of WRP in asphalt and how to effectively suppress the VOCs produced of HC-WRMA. First, the compatibility between WRP and asphalt was analyzed for HC-WRMA. Then, different VOCs inhibitors including activated carbon, 4A zeolite and nano calcium carbonate were added into HC-WRMA to inhibit VOCs emission. In addition, the high temperature rheological properties of HC-WRMA were studied using dynamic shear rheometer (DSR) and the low temperature properties of HC-WRMA were studied using differential scanning calorimetry (DSC). The optimum contents of WRP are 35% according to the storage stability experiments results. The GC–MS results show that different inhibitors have a significant inhibited effect on asphalt VOCs, and the addition of 6% nano calcium carbonate has the best inhibited effect. The DSR results show that complex modulus of HC-WRMA increased gradually with the increase of WRP content, and the phase angle decreased with the increase of WRP content, which indicates that the addition of WRP can improve the resistance deformation ability of asphalt and enhance the flexibility of asphalt. The DSC results show that the addition of excessive WRP has adverse effect on the low temperature performance of asphalt. Also, the Fourier transform infrared spectroscopy (FT-IR) results show that there are no chemical reaction and only physical blending between the WRP and asphalt. In short, HC-WRMA has broad development prospects in the future.

Study on Prevention and Treatment Strategy of Asphalt Ultraviolet (UV) Aging Based on UV Climate Zoning in China

The purpose of this paper, based on the amount of ultraviolet (UV) radiation in different areas of China, was to give the corresponding measures to prevent UV aging of asphalt. In this paper, based on the average annual amount of UV radiation in China in the past 30 years and the characteristics of UV aging of asphalt, the climatic zoning of UV radiation of asphalt in China was proposed. A variety of base asphalts and styrene–butadiene–styrene block copolymer (SBS) modified asphalts were selected to carry out a UV radiation test, and the relationship between UV radiation amount and viscosity, low-temperature performance, and the rheological properties of asphalt were studied. The equivalent aging indexes of asphalt during UV radiation were selected, the UV aging equation of asphalt was proposed, and the equivalent UV aging relationship among different UV climate zones was established. The prevention and control strategies of UV aging of asphalt among different zones were proposed, and the above theory was verified using a trial road. The main conclusions in the paper are presented: The climate zoning of asphalt UV radiation in China can be divided into three zones: zone I with an annual UV radiation less than or equal to 69.4 kW·h/m2 in the last 30 years; zone II with an annual UV radiation of 69.4~81.4 kW·h/m2 in the last 30 years; zone III with an annual UV radiation more than or equal to 81.4 kW·h/m2 in the last 30 years. The greater the amount of UV radiation, the greater the loss rate of penetration and ductility. For the same kind of asphalt, there is a relatively stable functional relationship between the loss rate and the amount of UV radiation. The results also show that UV radiation changes the proportion of viscous and elastic components in asphalt, showing that the proportion of viscous components decreases and the proportion of elastic components increases. The penetration loss rate and ductility loss rate of asphalt can be used as equivalent UV aging indexes of asphalt. Under the same outdoor UV irradiation time, for asphalt to achieve the same technical performance as zone I, the anti-UV ability of zone II needs to be improved by more than 5%, and that of zone III needs to be improved by more than 10%. Engineering practice has proved that the zoning established in this paper and the corresponding UV control measures are basically reasonable.

Effect of Ageing on Rheological Properties of Asphalt

This paper is to study the mechanism of aging on the rheological properties of the asphalt and make correlations with the actual field behavior of the binder. The effects of ageing on rheological properties of asphalt has been studied by Dynamic Shear Rheometer(DSR). Significant differences of rheological properties and composition were observed between fresh and aged asphalt. The results show that aging at low temperature increases the complex modulus of asphalt, but has little effect at high temperature.

Bitumen Rheological and Chemical Investigation

This paper is to study the mechanism of aging on the Rheological and Chemical Investigation of the bitumen and make correlations with the actual field behavior of the binder. The effects of ageing on rheological properties of asphalt has been studied by Bending Beam Rheometer(BBR). The objective of conducting these tests is to evaluate the performance of the bitumen in an aged and unaged states in relation to the effects of traffic speed and/or pavement temperature, traffic volume (number of load repetitions), and (thermal/load) cracking behavior.

Enhanced Storage Stability and Rheological Properties of Asphalt Modified by Activated Waste Rubber Powder.

Segregation of waste crumb rubber powder (WR) modified asphalt binders the large-scale application of WR in asphalt. The method of microwave activation combined with chemical activation (KMWR) was proposed to improve storage stability and rheological properties of WR modified asphalt in this work. Storage stability and rheological properties of virgin asphalt, MWR modified asphalt, and KMWR modified asphalt were comparatively studied by the standard segregation test, bending beam rheometer (BBR) test, and dynamic shear rheometer (DSR) test. The effect of composite activation on waste rubber powder particles was studied by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and Brunauer–Emmett–Teller (BET) tests. The main results showed that after the physical and chemical composite activation, the storage stability of waste rubber powder modified asphalt was significantly improved, WR modified asphalt had better crack resistance, better rutting resistance, and better fatigue performance. After physical and chemical activation, WR was desulfurized, and a large number of active groups was grafted on the WR particles.

Effect of application of metallurgical slag powders on physical and rheological properties of asphalt

Metallurgical slags are residues that are obtained in the manufacturing and smelting processes of metals, such as steel and copper. However, their use is limited because they may cause environmental problems at their disposal sites. This study aims to evaluate the effects of the addition of slag on the properties of slag-modified asphalts using three different slag proportions (3, 6, and 10% by weight of asphalt). Electric arc furnace slag, blast furnace slag, and copper slag were used to evaluate the effects of the addition of slag on their performance properties via physical and rheological tests. The results showed an improvement in the consistency of the slag-modified asphalts, decreasing the penetration rate and increasing the softening point. An enhancement in the short-term asphalt aging characteristics was also observed with the addition of slag. Finally, the rheological test results revealed an improvement in the resistance to permanent deformation with the addition of slag in neat asphalt, whereas no statistically significant results were observed when the slag content was increased.

Investigating binder aging during hot in-place recycling (HIR) of asphalt pavement

Hot in-place recycling (HIR) is considered as an effective way to reuse reclaimed asphalt pavement (RAP). Heating pavement is the core technology of HIR. To ensure construction workability, the pavement should be heated and held at a relatively high temperature. However, the high heating temperature of HIR may cause significant aging on the SBS modified asphalt, which is usually used in the pavement. The objective of this study is to understand the aging behavior of SBS modified asphalt in HIR and provide appropriate guidance for future HIR projects. In this research, eight kinds of asphalt binder samples were collected and extracted from different stages of a practical HIR project. They were then tested in terms of the chemical and rheological properties. The rheological properties of asphalt are evaluated by the frequency sweep testing and Multiple Stress Creep Recovery (MSCR) testing using the Dynamic Shear Rheometer (DSR). The chemical evolution during FTIR was tracked from Fourier Transform Infrared (FTIR) spectra and Gel Permeation Chromatography (GPC). The results of the experiments showed that the influence of long-term aging is quite significant and untreated pavement exhibits much lower elastic recovery due to the degradation of SBS polymer. HIR did cause some extent of extra aging to the treated pavement, Compared with Untreated, the Carbonyl index and molecular weight ratio of polymer of Heated (#3) are reduced by 34% and 39% respectively. The effect of heating gradient between different pavement depths is noticeable. The modulus of Surface is 2.69 times that of Bottom. The PB index of Surface is 0.37 times that of Bottom. There is no noticeable chemical reaction between the rejuvenator and the aged asphalt. After adding rejuvenator, the modulus of pavement decreased by 55%.

Rheological properties and aging performance of sulfur extended asphalt modified with recycled polyethylene waste

This study examines the effect of two different recycled plastic waste (RPW) which are high and low-density polyethylene (RHDPE and RLDPE) on the rheological/viscoelastic characteristics and aging performance of virgin asphalt and sulfur extended asphalt (SEA). Four dosages of the RPW additives representing 2%, 4%, 6%, and 8% by weight of the asphalt binder were investigated. The rheological characteristics of the RPW modified binders (virgin and SEA) are characterized at original and short-term aging conditions through the Rotational Viscometer (RV) and dynamic shear rheometer (DSR) tests. Fatigue performance is also characterized at the long-term aging condition. Also, high-temperature performance, dynamic storage stability (DSS), multiple stress creep and recovery (MSCR) are studied. Testing results show that RPWs lead to improved rutting and fatigue performance. Adding RPW to the virgin and SEA binders slows the binder oxidation reactions during the short-term aging. The Aging Index (AI) is found to be dependent on the asphalt rheological properties, amount/type of RPW, binder type, and temperature. RHDPE leads to an unstable modified virgin asphalt. Less than 4% RHDPE or 8% RLDPE with virgin asphalt show good DSS in terms of degradation and separation. The RPW with SEA meets the requirement of time degradation and separation set by the Federal Highway Administration (FHWA). The temperature susceptibility of asphalt binder decreases dramatically with the RPW modification making the asphalt binder more suitable for use at a wider range of temperatures.

Experimental and molecular dynamics simulation study on thermal, transport, and rheological properties of asphalt

The purpose of this study was to evaluate the thermal (glass transition temperature), transport (self-diffusion), and rheological (viscosity, storage and loss modulus) properties of asphalt via laboratory experiments and molecular dynamics simulations. A 12-component asphalt model was employed in the molecular dynamics simulations with the modified Amber-Cornell force field. The asphalt model with the specific force field was validated against experimental and literature density data at various temperatures. The transition from the glassy state to the viscoelastic regime was explored by calculating the glass transition temperature. The results were compared with results from the differential scanning calorimeter (DSC) experiments. The self-diffusivity was calculated at a broad temperature range. The viscosity at the viscoelastic liquid regime was measured in the laboratory and calculated with reverse non-equilibrium molecular dynamic (rNEMD) simulations at various temperatures. Laboratory dynamic shear rheological testing was conducted for a wide frequency range at 70 °C. Oscillatory shear was applied in the asphalt model for calculating the storage and loss moduli within the experimental frequency range.

Correlation analysis between aging behavior and rheological indices of asphalt binder

The aging of the asphalt binder seriously affects the performance of the asphalt pavement, so it is expected to obtain indices that can not only evaluate the aging resistance of the asphalt binder but also indicate the performance of the asphalt mixture. In this study, the changing of the rheological indices before and after asphalt aging were observed. The sensitivities to aging characterized by different rheological indices were also compared with each other. Moreover, the relationships among rheological indices were discussed. The results show that the aging has a significant impact on the rheological properties of asphalt. The addition of modifier obviously reduced the low-temperature relaxation modulus of asphalt and increased the absolute value of relaxation rate, thereby improving the low-temperature performance of asphalt road. The sensitivity analysis results of rheological indices to aging behavior show that rheological indice [R3.2kPa] obtained by multiple stress creep recovery test was most sensitive to short-term aging, while rheological indice [R]3.2kPa obtained by repeated creep recovery test was most sensitive to long-term aging, which helps to provide technical support for the quantitative characterization of the aging behavior of asphalt binder. Correlation analysis of rheological indices show that the indice mr(60 s) in frequency sweep test at low temperatures show a linear correlation with the indices Jnr3.2kPa in MSCR test and Nf in linear amplitude sweep test, indicating that the low-temperature relaxation rate of asphalt is closely related to its high temperature performance and fatigue performance.

Comparison of SBS-Modified Asphalt Rheological Properties during Simple-Aging Test

AbstractThe objective of this paper is to evaluate the effect of different aging times on the performance of styrene-butadiene-styrene (SBS) copolymer–modified asphalt. Two kinds of SBS-modified as...

Evaluation of phosphorus slag (PS) content and particle size on the performance modification effect of asphalt

To evaluate the modification effect of phosphorus slag powder (PSP) on the rheological performance of asphalt, five types of PSP with different particle sizes and different content were prepared and added into the AH-70 base asphalt. The dynamic shear rheometer (DSR) test was used to evaluate the influence of PSP content and particle size on the rheological properties of asphalt. Rolling thin film oven test (RTFOT) and pressure aging vessel (PAV) were used to simulate the asphalt aging after modification of PSP. The influence of aging conditions on the phosphorus slag modified asphalt (PSMA) was evaluated, and the impact of PSP on the function group of asphalt was analyzed by Fourier Transform Infrared spectroscopy (FTIR). The results indicated that the interaction between PSP and asphalt was mainly physical blending with some degree of chemical reactions. PSP was more sensitive to aged asphalt but less sensitive to original asphalt because it could react with some carbonyl groups. With the increase of PSP content, the shear complex modulus of PSMA increased first and then decreased, and the phase angle decreased first and then increased after RTFOT aging. With the increase of the specific surface area of PSP, the complex shear modulus of PSMA increased and the phase angle decreased. The result found that with the increase of the specific surface area, the high temperature rutting resistance and fatigue performance of asphalt was improved. This study provided important theoretical and practical guidance for the application of PSMA.

Study of the Effect of Aggregate Geometry Characteristics on the Rheology of Asphalt Mortar Using Newly Developed Material Rheological Property Test Analyzer and Aggregate Image Measurement System

Abstract A new rheometer developed in the laboratory and the Aggregate Image Measurement System (AIMS) were used to study the effect of aggregate geometry characteristics on the rheological properties of asphalt mortar. AIMS was used to investigate the geometry characteristics (angularity index and Form 2-D) of two aggregates including steel slag and basalt. The results showed that steel slag had a better Form 2-D and angularity index, representing a better particle distribution and shape property. A material rheological property test analyzer was applied to evaluate the rheological properties of pure and styrene-butadiene-styrene (SBS)-modified asphalt and their asphalt mortars at 20°C and 40°C, and then the data were modeled through the simulation software. As a kind of rigid body, the addition of aggregate had a great influence on the rheological properties of asphalt. The experiment results indicated that, after the addition of aggregate or SBS, the rheological model of asphalt samples was still Burges model accompanied by the change of rheological parameters. As a kind of temperature-sensitive material, temperature was the most important factor for determining the rheological properties of asphalt. The addition of SBS promoted the elastic deformation of asphalt and restrained the viscous deformation of asphalt. The effect of aggregates with high Form 2-D and angularity index on the rheological properties of asphalt was weaker.

Relation between Asphalt, Asphalt Mortar Properties and HMA Performance

The relationship among asphalt, mortar and mixture performance was analyzed by grey correlation method by means of asphalt rheological test and hot mix freeze-thaw split test in this paper. The results show that the rheological properties of asphalt as well as asphalt mortar are closely related to HMA performance. Rheological index has a good advantage in explaining HMA pavement diseases. Asphalt stiffness, cohesion, yield stress, rutting coefficient, multiple stress creep and recovery have a high correlation with the strength of the mixture; meanwhile, softening point, normal stress, interface bonding ability of asphalt mortar and volume index of mixture have a high correlation with the water stability of the mixture. In the evaluation of asphalt and asphalt mortar, methods such as stress creep recovery, stress scanning (yield stress, normal stress) and interface bond test should be further proposed and popularized.

Research on Rheological Properties of High‐Percentage Artificial RAP Binder with WMA Additives

With the development of pavement recycling technology, the requirement of reclaimed asphalt pavement (RAP) is substantially increasing. Warm‐mix recycled asphalt (WMRA) technology has made great progress, which can effectively decrease the working temperature and improve the RAP content. In this study, the rheological properties of recycled binders with incorporation of high‐percentage artificial RAP binder (30–70%) were evaluated using two types of warm‐mix asphalt (WMA) additives, i.e., polyethylene wax (R) and surfactant (M). The dynamic shear rheometer (DSR) and beam bending rheometer (BBR) tests were conducted on the recycled binders. The results showed that the temperature and frequency played an important role in determining the complex shear modulus of the high‐percentage WMRA binders. The dependency of phase angle on frequency increased after the long‐term aging. The WMA additive R had a relatively huge impact on the rheological properties of asphalt, which mainly occurred before the PAV aging of recycled asphalt binder; the WMA additive M had no significant impact on the rheological properties of recycled asphalt binder. The WMA additive R enhanced the low‐temperature rheology of recycled asphalt binder, while the WMA additive M enhanced the high‐temperature rheology of recycled asphalt binder. Both of these types of WMA additives improved the antifatigue performance of recycled asphalt binder. The increased content of RAP binder improved the high‐temperature performance and reduced the low‐temperature performance of the recycled asphalt binder. However, it had no obvious impact on the fatigue performance. In addition, there was a good linear relation between the RAP binder content and the two indexes of the multiple stress creep recovery (MSCR) test.

Physical properties and anti-aging characteristics of asphalt modified with nano-zinc oxide powder

Asphalt aging holds responsibility for fatigue damage of asphalt pavement. Incorporation of nano-zinc oxide (nano-ZnO) as modifier into asphalt can effectively improve anti-aging property of asphalt. In this work, different dosage of nano-ZnO was added to original asphalt to prepare modified asphalt, and physical properties of nano-ZnO modified asphalt, including storage stability, penetration (25 °C), softening point and ductility (5 °C) were tested. Effect of nano-ZnO on the rheological properties of asphalt was studied by testing rheological properties of modified asphalt before and after aging. In addition, fatigue properties of asphalt with different nano-ZnO dosage were analyzed by linear amplitude sweep (LAS) test. Furthermore, anti-aging characteristics of nano-ZnO modified asphalt were characterized by thin film oven test (TFOT) and ultraviolet aging (UV-aging) test and mechanism was interpreted by UV–visible-infrared absorption test. The results show that nano-ZnO can influence penetration (25 °C), softening point, ductility (5 °C) and storage stability of asphalt. Nano-ZnO can improve complex shear modulus (G*), phase angle (δ) and fatigue performance. Addition of nano-ZnO can evidently improve anti-UV aging ability of asphalt and make asphalt show certain viscosity recovery during aging process. In addition, nano-ZnO has strong absorption characteristics to ultraviolet light with more than 95% absorption rate, which reflects its superiority as anti-UV aging modifier for asphalt. UV absorption of nano-ZnO modified asphalt is enhanced several times than that of original asphalt. Asphalt modified with reasonable nano-ZnO dosage possesses significant and evident anti-aging characteristics.