Pressure Aging Vessel Test Research Articles

Effect of microwave and deodorant treatments on long-term aging characteristics of crumb rubber modified asphalt

This research examined and compared the effect of microwave and deodorant treatments on the rheological and microscopic characteristics of crumb rubber modified asphalt (CRMA) after long-term aging. Although the emissions from the asphalt modified by microwave treatment of crumb rubber (CR-micr) or high-alkane alcohol deodorant treatment of crumb rubber (CR-de) are reduced significantly compared with the ordinary CRMA, the research on their rheological and microscopic properties after aging is insufficient (especially for the CRMA with CR-de), which may pose a potential risk to their application in road engineering. To address this issue, this paper first used the rolling thin film oven and pressure aging vessel test to imitate the long-term aging of CRMAs. Then, the rheological properties of aged CRMA samples were evaluated using a dynamic shear rheometer and a bending beam rheometer. Meanwhile, the surface micromorphology, micromechanical characteristics and the chemical functional groups of CRMA samples before and after long-term aging were characterized by atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). The results demonstrated that the microwave treatment can enhance the fatigue life of the long-term aged CRMA by approximately 29 % under 8 % CR content and 3 % strain level, while effectively improve the resistance to low-temperature cracking. Meanwhile, after long-term aging, the carbonyl index of CRMA with CR-micr is 36 % lower than that of CRMA with CR-de and 50 % lower than that of ordinary CRMA. The micromechanical modulus of CRMA with CR-micr is also lower than that of CRMA with CR-de and ordinary CRMA. These findings manifest that the microwave treatment can improve the ability of CRMA to resist long-term aging, and the deodorant treatment does not have an adverse effect on this ability.

Effects of Silicone Rubber on Rheological Properties and Aging Characteristics of Asphalt Binder.

Silicone rubber (SR) is a kind of polymer insulation material with excellent performance. With the service life of silicone rubber products reaching the limit, how to dispose of waste silicone rubber is an urgent problem to be solved. In this paper, silicone rubber-modified asphalt binder (SRMA) was prepared by SR and 90# base asphalt binder. The simulated short-term aging and long-term aging tests of SRMA were carried out using the thin film oven aging test (TFOT) and pressure aging vessel test (PAV). The rotary viscosity test and dynamic shear rheological test (DSR) were applied to the rheological properties of SRMA before and after aging. The degradation degree and chemical composition changes of SR were explored by the toluene insoluble matter test, Fourier transform infrared spectroscopy (FTIR), and a Fluorescence microscope (FM). The results demonstrate that SR can significantly affect the aging resistance, fatigue life, and high-temperature stability of SRMA. As the content of SR rose, the elastic component in SRMA increased, leading to a nice performance in stability at high temperatures and fatigue resistance. However, excessive content (14%wt and 16%wt) had a negative influence on the performance of SRMA. So, the optimal content was speculated to be between 12% and 14%. Furthermore, SR and asphalt binder would be aged and degraded together in the aging process, and this phenomenon was more obvious during long-term aging.

The Effects of Aging on Microstructures and Rheological Properties of Modified Asphalt with GO/SBS Composite.

This work aimed to investigate the effects of aging on the microstructures and rheological properties of modified asphalt with a GO/SBS composite, since the styrene-butadiene-styrene block copolymer is potentially compatible with graphene oxide (GO). The GO/SBS composites, which were used as a kind of modifier, were prepared via the solution-blending method. GO/SBS composites with varying GO contents were employed to prepare the GO/SBS-compound-modified asphalt (GO/SBS-MA). Then, the GO/SBS-MA underwent PAV (pressure aging vessel) or UV (ultraviolet) aging tests to simulate different aging circumstances. The microstructures of the asphalt binders were studied using FTIR (Fourier-transform infrared spectroscopy) and AFM (atomic force microscope) tests. Moreover, DSR (dynamic shear rheometer) and BBR (bending beam rheometer) experiments were carried out to investigate the rheological properties of the GO/SBS-MA. The results showed that the addition of GO improved the high-temperature stability of the asphalt binder while slightly impairing its performance at low temperatures. GO restrained the formation of carbonyl and sulfoxide groups as well as the breakdown of C=C bonds in the polybutadiene (PB) segment, promoting the anti-aging performance of GO/SBS-MA. Furthermore, the interactions between the GO/SBS and the asphalt binder resulted in the formation of needle-like aggregates, enhancing the stability of the asphalt binder. The asphalt binders with a higher content of graphene oxide (GO) exhibited not only a better high-temperature performance, but also a better aging resistance. It was concluded that the macroscopic properties and microstructures were significantly affected by GO, and a moderate increase in the amount of GO could contribute to a better aging resistance for GO/SBS-MA.

Comparison of elvaloy and styrene-butadiene-styrene added polymer modified bitumen

One of the methods used to produce road pavements resistant to increased traffic volume and harsh environmental conditions is to improve the properties of bituminous binders, such as high temperature resistance and aging resistance, by using various additives. Styrene-Butadiene-Styrene and Elvaloy are two different commercial additives that are frequently used in pavement construction. In this study, the performance of three different B50/70 grade pure bitumens was modified by using Elvaloy at 1.6%, 1.7%, and 1.8%, and five different B50/70 grade pure bitumens were modified using 4.0%, 4.5%, and 5.0% Styrene-Butadiene-Styrene. Penetration, softening point, elastic recovery, flash point, storage stability, dynamic shear rheometer, beam bending rheometer, rotational thin film oven, and pressure aging vessel tests were applied to the binders in accordance with the Polymer Modified Bitumen technical specifications. According to the test results, it was determined that the additive rates for both modifiers are the optimum values in accordance with the specification. The results of the storage stability tests also showed that the non-homogeneous dispersion of the Styrene-Butadiene-Styrene modified binders during mixing had a significant effect on the behaviour of the binder after storage.

Effects of aging behavior on macro and micro characterizations of surfactant–crumb rubber asphalt binders

Asphalt aging process degenerates the performance and shortens the lifetime of the pavement, while using warm mix additive and crumb rubber modifier can improve the main negative distress. In this study, aged crumb rubber modified asphalt binder (CRMAB) with and without surfactant (0.6% SK) additive were designed through rolling thin film oven and pressure aging vessel test. The dynamic shear rheometer, bending-beam rheometer, fourier transform infrared spectroscopy, and atomic force microscopy tests were conducted to identify the effects of aging behavior on the macro-rheological properties, chemical constituents, and morphological characteristics of CRMAB and surfactant–crumb rubber modified asphalt binder (S-CRMAB). The findings from micro and macro analysis showed that aging increases carbonyl, sulfoxide, and aliphatic components, decreases aliphatic branched components, causing higher high-temperature rheology, lower low-temperaturen and fatigue performance. However, SK improves its aging resistance and relaxation ability. Moreover, the appearance of uniform hills–valleys and “round and bright lamellar” structures on the surface of 3D and 2D topographic images of S-CRMAB, respectively, indicating the surface roughness decreases, and microstructural stability gets enhanced.

Additives Influence on the Properties of Asphalt Binders: A Case Study

This study investigated the impact of using modified bitumen binders and additives to enhance the physical characteristics of asphalt mixtures at high, medium, and low temperatures. Both basic and rheological characteristics of the bituminous binders were tested by adding Styrene-Butadiene-Styrene, a type of thermoplastic elastomer, as a chemical additive to asphalt mixtures at various fractions (3.5%, 4%, and 4.5%), and two kinds of modified Bitumen: Kraton styrene block copolymers and Europrene (SOL T 6302). The following methods were used to test the properties of the binders: needle penetration, ductility, softening point, resistance to hardening when exposed to heat and air, Pressure Aging Vessel test dynamic (PAV), Shear Rheometer (DSR), Bending Beam Rheometer (BBR), direct tension test, and storage stability. The results showed that the best properties of the asphalt concentration were observed when using 4% of additives, while the penetration of Bitumen was reduced to 27.2% and 30.3% when adding Kraton and Europrene SOL T6302, respectively. The influence of adding 4.0% additives decreased the bulk specific gravity to 2.395. Laboratory tests showed how the mentioned chemical additives directly affect the properties of the mixture and the binder by increasing their viscosity.

Green and sustainable production of waste styrofoam-modified bitumen: a laboratory-based investigation on physical, rheological properties, and storage stability.

The motivation of this study was to investigate the feasibility of production of green and sustainable bitumen modified with waste styrofoam (WS) that contributed to the base bitumen in certain rate. To achieve it, not only basic but also rheological properties and storage stability of WS-modified bitumen were taken into consideration. In this respect, bitumen with 70/100 penetration grade was modified with WS in different rates ranging from 1 to 5% with 1% increment. Basic test methods including penetration, softening point, rotational viscometer were conducted on the bitumen samples to analyze physical properties, while dynamic shear rheometer and bending beam rheometer tests were performed on the samples for rheological assessment. Rolling thin film oven and pressure aging vessel tests, which are aging methods in rheological evaluation, were followed to supply short- and long-term aged samples, respectively. Storage stability test was conducted on the modified samples to determine the compatibility between the two materials at different contribution WS rates. The results showed that significant changes occur on both physical and rheological properties of WS-modified bitumen. Compatibility between WS and bitumen was not observed except of the bitumen modified up to 2% WS as examined with softening point, but up to 3% WS as examined with penetration test. Overall, disposal of WS within bitumen modification can be a green and sustainable as considering the ecological and economic aspects.

Effects of Gilsonite on Performance Properties of Bitumen

The effectiveness of natural Gilsonite on the performance properties of modified bitumens was studied. Three samples having different ratios of Gilsonite that are 6%, 8% and 10% by weight of base bitumen which was PG 64-16 grade were prepared. The physical properties and storage stabilities of four samples were investigated by means of conventional tests. The short-term and long-term aging processes of bitumens were conducted with rolling thin oven and pressure aging vessel tests, respectively. Rheological properties of bitumens were examined by means of Superpave tests such as rotational viscosity, dynamic shear rheometer and bending beam rheometer. After the rheological study, the low and high temperature performance classes of bitumens were determined by the Superpave specification. The results showed that natural Gilsonite-modified bitumens provide improvement in rheological and physical properties of bitumen, and were found highly compatible with base bitumen. Gilsonite additive significantly increased stiffness and viscosity of bitumen, and improved the resistance against fatigue cracking and rutting of bitumen, without causing a reduction in thermal cracking resistance of bitumen.

Comparative Evaluation of Aging Effect Difference between Aging Patterns for Asphalt Binder and Mixture

Abstract Aging simulation methods for asphalt materials can be generally classified into two types: for asphalt binder and for asphalt mixture. Nevertheless, there exists the aging effect difference between aging patterns for asphalt binder and mixture due to differences in aging experimental conditions. The comparison of the aging effect difference between aging patterns for asphalt binder and mixture contributes to building the relationship and thus achieving a conversion of asphalt aging degree between its binder and mixture aging patterns. In this research, aging effect differences between aging patterns for binder and mixture were investigated in terms of short-term aging, long-term aging, and ultraviolet radiation (UV) aging. The binders were collected before and after different aging patterns and then characterized by physical, rheological, and chemical tests. The results indicate that the aging effect difference between thin film oven test and short-term oven aging test is slight, whereas the aging effect of pressure aging vessel test significantly outweighs the effects of long-term aging patterns with loose or compacted specimens. As for photo oxidation aging, the aging effect ranking from the highest to the lowest is UV aging with loose specimen, UV aging for binder, and UV aging with compacted specimen. In addition, regardless of long-term or UV aging pattern for mixture, the aging degree of binder in loose specimen is more serious than that in compacted specimen.

Impact of reactive oxygen species on bitumen aging – The Viennese binder aging method

Bitumen aging has a significant impact on the performance and durability of road pavements. To predict the aging behavior of roads and its binder, realistic long-term aging simulation is necessary. The common long-term aging simulation in the laboratory is a Pressure Aging Vessel test (PAV) subsequent to Rolling Thin Film OVen Test (RTFOT). The PAV oxidizes bitumen by applying high pressure and temperature but neglects the presence of reactive oxygen species (ROS) that are found in the atmosphere and near the pavement surface.We present a new method, the Viennese Binder Aging (VBA), that incorporates two ROS (O3 and NOX) into its ageing atmosphere. This study focuses on the fundamental impact of these ROS by varying their concentration and analyzing their effect on bitumen aging. To compare the VBA to field and PAV aged samples, DSR, FTIR spectroscopy and fluorescence microscopy were applied. Their results revealed that VBA could reach and even surpass RTFOT + PAV level of aging within three days. Their analysis and evaluation will help us to gain a better fundamental understanding of realistic aging and its simulation in the laboratory.

Synergetic Effect of Nano‐ZnO and Trinidad Lake Asphalt for Antiaging Properties of SBS‐Modified Asphalt

In order to address the influence of aging on the performance degradation of SBS‐modified asphalt, a composite modification of SBS‐modified asphalt by nano‐zinc oxide (nano‐ZnO) and Trinidad Lake asphalt (TLA) was proposed. Several tests were conducted after adding nano‐ZnO and TLA to SBS‐modified asphalt, including a rotary film oven test (RTFOT), ultraviolet aging (UV), and the pressure aging vessel test (PAV). The conventional physical index, rheological index, and four‐component content of SBS‐modified asphalt before and after three aging modes were tested, and the characteristic functional groups in SBS‐modified asphalt were tracked and analyzed by Fourier transform infrared spectroscopy (FTIR). The results show that the effects of aging on the rheological properties of SBS‐modified asphalt are clearly reduced by adding different proportions of nano‐ZnO and TLA in the process of thermal oxygen aging and the ultraviolet aging test, and the antiaging ability of SBS‐modified asphalt is clearly improved. To improve the conventional performance and rheological properties of SBS‐modified asphalt, an incorporation ratio of 3% nano‐ZnO + 25% TLA was proposed. At the same time, the increased rate of heavy components and the change index of the colloidal instability index in the SBS‐modified asphalt under the blending ratio were significantly lower than the blank SBS‐modified asphalt samples in the same aging mode. FTIR spectra also showed that SBS‐modified asphalt performance deterioration were mainly caused by long‐term aging and ultraviolet aging. The addition of nano‐ZnO and TLA effectively reduced the increase of carbonyl groups and the breakage of the C=C double bond in butadiene and synergistically improved the comprehensive aging resistance of SBS‐modified asphalt. Therefore, the use of this modification is an effective method to solve the aging problem of SBS‐modified asphalt.

Effect of long-term laboratory aging on rheological properties and cracking resistance of polymer-modified asphalt binders at intermediate and low temperature range

Aging of modified asphalt binder has a great influence on its rheological property and paving performance, and decreases the quality of asphalt pavements. The primary objectives of this study were to investigate the effect of long-term laboratory aging on rheological properties and cracking resistance of polymer-modified asphalt binders at intermediate and low temperature range, and to analyze different evaluation indexes. SBS modified asphalt and two kinds of SBS/crumb rubber compound modified asphalt were subjected to Rolling Thin Film Oven (RTFO) test and 20 h, 40 h, 60 h Pressure Aging Vessel (PAV) test. Two rheological methods (frequency sweep test and Bending Beam Rheometer test) and a conventional test (Fraass breaking point test) were applied. Experimental results indicate that the studied binders tend to be more viscous at relatively low loading frequencies and harder after aging, and the ability to relax internal stress declines. Master curves and aging sensitivity analysis show that after 40 h PAV test, the effect of aging on polymer-modified asphalt binders rheological properties and cracking resistance becomes insignificant. The phase angle master curve can well reflect the effect of aging on asphalt binders rheological properties since the shape of phase angle master curve is obviously different before and after aging. Besides, critical temperature from BBR and Fraass breaking point tests can only be regarded as a reference of the minimum service temperature of asphalt pavements, and it can hardly reflect the impact of aging on materials property. While Glover-Rowe (G-R) parameter and ΔTc are well-related to asphalt binders rheological and physical properties when used to evaluate the age-related cracking resistance of asphalt binders. Besides, SR2 compound modified asphalt binder exhibits a better cracking resistance compared with the other two binders. Its G-R values range from 5.09 to 19.24 kPa among the whole aging conditions, besides, both of the minimum critical and Fraass breaking temperatures are under –23.41 °C.

Effect of Aging on Characteristics of Bitumen Modified with Waste Lime Sludge

Abstract The design of pavement must be carried out to make it capable of evenly transferring the wheel load to the subgrade soil without exceeding its bearing capacity. However, failure occurs before the design life because of structural defects shown by pavements, such as low skid resistance, fatigue, and rutting. Because low-temperature cracking is more predominant in cold-temperature regions, this aspect of failure is considered within the future scope of study. To address this concern, waste lime sludge was added to improve the properties of bitumen in the present research work. In order to examine the effect of aging, the rolling thin-film oven test was conducted to replicate the short-term aging process, and pressure aging vessel test was used to resemble long-term aging. The viscosity test, softening point test, and penetration test were carried out to assess the physical properties, whereas the dynamic shear rheometer test was conducted to investigate the rheological properties of aged and unaged bitumen binders. It is observed that sludge acts as an aging inhibitor. The complex modulus was enhanced as a result of addition of sludge up to 20 %, which also lowered the values of phase angle, depicting high resistance to permanent deformation. The rutting and fatigue resistances of the binder improved, and soft grade bitumen was converted to hard grade bitumen.

Physical and rheological evaluation of aging behaviors of SBS modified asphalt with thermochromic powders

Styrene-butadiene-styrene copolymer (SBS) modified asphalt is widely utilized in road construction. However, aging effect on SBS modified asphalt is still a serious problem that needs to be resolved. It has been demonstrated that thermochromic materials can-not only adjust the road surface temperature, but also improve the aging resistance of base asphalt. This paper mainly investigated the effects of different content (0, 2, 4, 6, 8%) of red thermochromic powders (RTP) on the thermal oxidizing aging of SBS modified asphalt. Thin film oven test (TFOT), pressure aging vessel test (PAV) and ultraviolet radiation (UV), were used to simulate thermo-oxidative aging and ultraviolet aging of RTP binders, respectively. Physical and rheological properties of RTP binders before and after three aging methods were discussed. The results displayed that the red thermochromic powders had a slight effect on high-temperature stability of SBS modified asphalt, while the low-temperature performance grade of the SBS modified asphalt could be improved with the introduction of RTP. Aging behaviors of RTP asphalt binder could be effectively prevented in comparison with blank sample, indicating its good aging resistance which is in accordance with changes in physical and rheological properties of the binders before and after aging. In addition, 2% and 4% RTP binders showed superior aging resistance than 6% and 8% RTP binders.

Effects of nanocharcoal coconut-shell ash on the physical and rheological properties of bitumen

Bitumen properties which correspond to high resistance to traffic and temperature are the prime requirements in prolonging the pavement life. To achieve these requirements, nanoscale materials are considered as potential candidates to increase pavement life. Therefore, to fulfill the need for sustainable structures, this research focused on nanosized (1–100 nm) charcoal from coconut-shell waste as an additive in bitumen. Particle-size analysis and transmission electron microscopy indicated that 15 h of ball-mill grinding produced nanocharcoal ash (NCA) with an average size of 57.7 nm. Then, 0% (control), 1.5%, 3%, 4.5%, 6%, or 7.5% NCA by weight of bitumen PEN 60/70 was added. Penetration, softening point, viscosity, ductility, and dynamic shear rheometer (DSR) tests were performed to investigate the physical and rheological properties of the modified bitumen. Rolling thin film oven and pressure aging vessel tests were used to simulate the aging properties of the bitumen. Results showed that NCA decreased the penetration and increased the softening point of the bitumen, whereas viscosity increased with increased NCA percentage. High rutting and cracking resistance at failure temperatures of 76 and 22 °C, respectively, in the modified bitumen were revealed by the DSR test. Notably, 6% NCA was the optimum content that can improve rutting and cracking resistance.

Physical, rheological and chemical characterization of aging behaviors of thermochromic asphalt binder

As an innovative road material, thermochromic asphalt binder has great effect on keeping the surface temperature of pavement within relatively reasonable range. The objective of this paper was to investigate the anti-aging properties of asphalts containing 0, 2, 4, 6, 8% content of black thermochromic powders (named as blank sample, 2, 4, 6, 8% BTP binder for convenience). Three aging methods, including thin film oven test, pressure aging vessel test and ultraviolet radiation, were applied to simulate thermal and photo oxidation aging of asphalt, respectively. Physical and rheological properties of binders with and without thermochromic powders were measured before and after three aging methods. The results show that the introduction of black thermochromic powders could improve thermal stability and low-temperature cracking performance of asphalt binder. After three aging methods, all of thermochromic asphalt binders exhibit better aging resistance than blank sample by physical, rheological aging indices, and 4% is the optimal content in which thermochromic asphalt binder synthetically exhibits the best aging resistance. In addition, based on grey relational analysis (GRA), the aging indices of complex modulus aging index (CAI) and viscosity aging index (VAI) are more reliable in aging evaluation.

Aging rheological characteristics of SBR modified asphalt with multi-dimensional nanomaterials

The purpose of this work is to research the influence of multi-dimensional nanomaterials composed of surface modified nano-zinc oxide (nano-ZnO) and organic expanded vermiculite (OEVMT) on rheological characteristics of styrene butadiene rubber modified asphalt (SBRMA) before and after different aging methods. The styrene butadiene rubber modified asphalts (SBRMAs) with various proportions multi-dimensional nanomaterials were produced by melt blending method. All binders were aged by rolling thin film oven test (RTFOT), pressure aging vessel (PAV) and ultraviolet (UV) aging. Dynamic shear rheometer (DSR) was utilized to test the rheological properties of all samples, as well as the performance grade (PG) of all binders was checked. The results show that the addition of multi-dimensional nanomaterials can enhance the shear deformation resistance and elastic behavior of SBRMA. Based on the RTFOT, PAV and UV aging test results, both thermal oxidative and photo oxidative aging resistance of SBRMA can be improved significantly by introducing multi-dimensional nanomaterials. Moreover, the optimal proportion of multi-dimensional nanomaterials in SBRMA is confirmed as 1%OEVMT+3%nano-ZnO. Besides, the PG test result verifies that the PG of SBRMA after 1%OEVMT+3%nano-ZnO modifying maintains unchanged.

The Utilization of Graphene Oxide in Traditional Construction Materials: Asphalt.

In the advanced research fields of solar cell and energy storing materials, graphene and graphene oxide (GO) are two of the most promising materials due to their high specific surface area, and excellent electrical and physical properties. However, they was seldom studied in the traditional materials because of their high cost. Nowadays, graphene and GO are much cheaper than before with the development of production technologies, which provides the possibility of using these extraordinary materials in the traditional construction industry. In this paper, GO was selected as a nano-material to modify two different asphalts. Then a thin film oven test and a pressure aging vessel test were applied to simulate the aging of GO-modified asphalts. After thermal aging, basic physical properties (softening point and penetration) were tested for the samples which were introduced at different mass ratios of GO (1% and 3%) to asphalt. In addition, rheological properties were tested to investigate how GO could influence the asphalts by dynamic shearing rheometer tests. Finally, some interesting findings and potential utilization (warm mixing and flame retardants) of GO in asphalt pavement construction were explained.

Effect of different rejuvenators on the properties of aged SBS modified asphalt

ABSTRACTThe styrene-butadiene-styrene copolymer (SBS)–modified asphalt was aged by pressure aging vessel test. The effect of different content of rejuvenators on the physical and rheological properties of aged SBS-modified asphalt was investigated. The results showed that with the increase of the content, the physical and rheological properties of the aged SBS-modified asphalt are restored more significantly. Three kinds of rejuvenators were used to rejuvenate the properties of aged SBS-modified asphalt. It can be concluded that the improvement of rejuvenator-III on the properties of aged SBS-modified asphalt is the most obvious. The results also indicate that the rheological behavior of the aged SBS-modified asphalt is improved obviously by the rejuvenator.

Analytical, morphological, and rheological behavior of sulphur-extended-binder

Bituminous material is a limited natural resource mainly used in hot mix asphalt production. The high costs coupled with the large amounts required have been forcing pavement engineers to find cost effective alternative materials that can be used as extenders or partial substitutes. This prohibitive cost factor led this paper to focus on the utilization of abundant granular sulphur as an extender for the more expensive bituminous material. In this study, sulphur-extended binders were prepared by using a 50/70 grade bitumen and by increasing the amounts of granular sulphur as an extension up to a maximum 50% by weight. The samples were then exposed to short and long-term aging by performing the rolling thin film oven and pressure aging vessel tests. Aged and virgin samples were then further tested using analytical, rheological, and morphological testing methods. The promising results demonstrate that the sulphur-extended binder not only increases the performance of the neat bitumen, but can also lower overall costs.