High Temperature Performance Evaluation Research Articles

High-Temperature Performance Evaluation of a Novel Graphene-Based Aerogel

High-Temperature Performance Evaluation of a Novel Graphene-Based Aerogel

Study on high-temperature performance evaluation of asphalt mixtures with anti-rutting additives

<abstract><p>In order to investigate the asphalt mixture enhancement due to the granular anti-rutting additives, the multiple stress creep recovery (MSCR) test and wheel tracking test were performed to examine the effects of three anti-rutting additives on the high-temperature performance of binders and mixtures, respectively. Further, the interaction mechanism between anti-rutting additives and asphalt binder was revealed via a fluorescence microscopy (FM) test. The results indicate that the incorporation of anti-rutting additives causes a substantial increase in elasticity behavior for binders, along with a massive enhancement of dynamic stability for mixtures. Further, the enhancement of performance is not conclusively determined by the compatibility between the additive and asphalt. Instead, unmelted viscous-flow additives contribute to the enhancement of mixtures by interlocking, filling voids, cementing and wrapping the aggregate, which are essential mechanisms of mixture modification. This study contributes to selecting appropriate additives in engineering and enhancing anti-rutting additives based on their modification mechanism.</p></abstract>

Approach for accurately characterizing nonlinear viscoelastic and nonrecoverable properties of asphalt binders based on MSCR test

The multiple stress creep and recovery (MSCR) test has been widely accepted as a more practical method for accessing the rutting performance of asphalt binders than the conventional Superpave rutting factor test. Nevertheless, there still exists a major concern that 9-s recovery time in each cycle may not guarantee a sufficient recovery of the recoverable viscoelastic strain, especially for modified asphalts, and this could result in a potential inaccuracy in characterizing rutting resistance of binders. To effectively separate the recoverable nonlinear viscoelastic (NLVE) and nonrecoverable responses in the MSCR test, this paper presents a new approach that adopts an additional one-cycle low-stress creep and recovery (LSCR) test and the Schapery’s NLVE model in analyzing the MSCR test data. The LSCR test, covering the entire duration of the MSCR test (200 s), can well determine the linear viscoelastic (LVE) recoverable properties that the Schapery’s model requires for NLVE analysis. The results show that with the recoverable and nonrecoverable responses accurately isolated, the proposed approach rigorously redefines the indicators of the percent recovery R and nonrecoverable creep compliance Jnr in the MSCR test, and therefore effectively eliminates the inaccuracy of the original indicators caused by incomplete recovery of the recoverable strain component in each cycle. Also, the developed method exactly characterizes stress dependence and permanent deformation resistance of asphalt binder, thus offering an effective and accurate approach for high-temperature performance evaluation of asphalt binders.

Effective utilization of high-temperature sulfides in coated form on steel fibers for brake pad application and evaluating its tribological performance

This research work is to explore the novel multi-metal sulfide-coated steel fiber for tribological application. The study focuses on maximizing the efficiency of sulfides utilization by bringing the multi-metal sulfides into contact plateaus. Totally four variants of multi-metal sulfide-coated steel fibers were developed and evaluated for their tribological performance by partially and fully replacing the commercial steel fiber in the composition of the brake pad. The tribological performance of the brake pads was evaluated using IS2742 standards introduced with the customized fade3 test for high-temperature performance evaluation. The results showed fully replaced coated steel fiber with the coating material combination of 70 wt% multi-metal sulfide mix and 30 wt% of the binder.

High Temperature Performance Evaluation of High Viscosity Asphalt at Different Aging Degrees Based on Multiple Stress Creep Recovery Test

In order to investigate the effect of high temperature on the performance of three high viscous asphalt in company with various aging degrees (ADs), multiple stress creep recovery (MSCR) test was employed. CRR and irrecoverable compliance were also carried out to measure the high temperature resistance of high viscous asphalt to external loading in the presence of various aging conditions (ACs) as well as to examine the sensitivity of high viscous asphalt towards the stress. The findings of the study demonstrated that after short- and long-term aging, the high-viscosity asphalt turned harder. Also, type I high-viscosity asphalt was observed to have the greatest deformation resistance acted upon by various stress fields and ACs. Furthermore, in company with various ACs, while the average creep recovery rate (CRR) of Type I and Type II high-viscosity asphalt was found to be higher than that of the SBS modified asphalt, the average irrecoverable compliance was observed to be smaller. This indicated the significant effect of high-viscosity modifiers on the improvement of the elastic recovery performance of asphalt and its resistance to high temperature flow deformation. Contrary to the order of their CRRs, the magnitude of stress sensitivity of the three high-viscosity asphalt at various ADs was observed to be type II < type I < SBS modified asphalt, indicating a good negative correlation between stress sensitivity and average CRR. Furthermore, the obtained results revealed that, in the presence of various ACs, the high temperature viscoelastic qualities of high viscosity modified asphalt is considered by the MSCR test. Also, to comprehensively evaluate the high temperature performance of high viscosity modified asphalt at various Ads, the use of such indexes as the average CRR, average irrecoverable compliance and stress sensitivity coefficient were essential.

High-Temperature Performance Evaluation of Asphalt Mixtures by Adding Short-Chopped Basalt Fiber

Adding basalt fiber (BF) can effectively enhance the performance of asphalt mixtures and improve the service quality of asphalt pavement. However, the effect of BF on the high-temperature performance of different types of asphalt mixtures and systematic high-temperature performance test analysis are still not well known. To address this issue, three typical types of asphalt mixtures of AC-13, SMA-13, and SUP-13 were selected. Wheel tracking test, uniaxial penetration test, dynamic modulus test, and dynamic creep test were conducted. In addition, relevant parameters of dynamic stability, penetration strength, dynamic modulus index, and flow number were analyzed. The results showed that adding BF into the asphalt mixture could improve the dynamic stability, penetration strength, dynamic modulus index, and flow number significantly, indicating that adding basalt fiber is an effective solution to the rutting deformation damage of asphalt pavement. Moreover, the parameter of dynamic stability presented an approximate polynomial correlation with penetration strength, dynamic modulus index, and flow number, respectively. These findings provide a certain theoretical reference for evaluating the high-temperature performance of BF-modified asphalt mixtures.

Research on High-Temperature Evaluation Indexes and Performance of Qingchuan Rock-SBS Composite Modified Asphalt.

The phenomenon of structural destabilization damage to asphalt pavement is becoming increasingly serious as a result of high temperatures and heavy traffic. Considering the advantages of Qingchuan rock asphalt (QRA) in its durability, high-temperature rutting resistance, and good compatibility with asphalt, it was proposed to compound rock asphalt with SBS to ameliorate the high-temperature performance of asphalt. In this study, DSR and BBR were used to determine the rheological properties of Qingchuan rock-modified asphalt (QRMA) and Qingchuan rock-SBS-modified asphalt (QRA-SBSMA), and the optimum blending amount of rock asphalt was determined based on the PG classification results. Secondly, four different structures of '30 mm AC-10 upper layer (70-A, QRMA, SBSMA, QRA-SBSMA) + 50 mm AC-16 lower layer (70-A)' double-layer composite specimens were prepared. Multiple high-temperature performance evaluation indexes (G*/sinδ, Ds, rutting depth, micro-strain, Fn, modulus) were used to assess the improvement effect of QRA. Finally, using a 1/3 scale accelerated loading testing machine, we simulated high-temperature, water, and high-temperature coupled environments to assess the impact of high temperature and water on the performance of QRMA and QRA-SBSMA, respectively. The findings demonstrated that QRA can increase the PG classification of 70-A and SBSMA as well as its resistance to high-temperature deformation. Multi-index comprehensive evaluation methods were used to consummate the asphalt high-temperature evaluation system. The QRA-SBSMA had the smallest rutting depth and creep rate and the largest dynamic modulus, characterizing its ability to optimally resist high-temperature rutting and deformation.

Assessment of testing methods for higher temperature performance of emulsified asphalt

High-temperature features are crucial for evaluating the performance of emulsified asphalt. As effective binders, evaporation residues directly determine the high-temperature performance of emulsified asphalt. This study aims to systematically investigate the laboratory preparation process for different emulsified asphalt evaporation residues (EAERs) and proposes appropriate testing and evaluation methods. First, emulsified asphalt was prepared using five different material samples (cations M, A, L, T, and latex). Secondly, three evaporation methods were used to obtain EAERs: the direct heating method, low-temperature evaporation method, and improved evaporation method. Then, the high-temperature rheological parameters were determined using the Brookfield viscosity test, temperature-sweep test, and multiple stress creep recovery tests. Finally, microscopic test methods were adopted for the mechanism analysis, including the fourier transform infrared spectroscopy (FTIR) and the atomic force microscopy (AFM). The results show that different evaporation methods can significantly affect the high temperature performance evaluation results of EAERs. These differences are more obvious between high temperature evaporation and low temperature evaporation conditions. Moreover, the rutting resistance factor and phase angle of styrene-butadiene rubber (SBR) modified emulsified asphalt residues prepared by direct heating method present completely different change laws. From the FTIR and the AFM tests, it is found that these different change laws are due to the chemical reaction during the preparation of SBR modified emulsified asphalt residue by direct heating, which may be the aging of material or the degradation of polymer. In conclusion, the low-temperature evaporation method is recommended to prepare EAERs for a more realistic evaluation of the high-temperature performance of emulsified asphalt. The improved evaporation method should be prioritized as it further standardizes the parameters for subsequent laboratory testing.

Research on High-Temperature Rheological Properties of Emulsified Asphalt Mastics and Their Influencing Factors

The high-temperature rheological properties of emulsified asphalt mastics have a significant impact on the service performance of cold recycled mixtures with asphalt emulsions. In this paper, a dynamic shear rheological (DSR) test and a multiple stress creep recovery (MSCR) test are carried out to analyze the influence of tunneling coal gangue powder (TCGP), portland cement (PC), limestone powder (LP), and four kinds of filler binder ratio (F/B) on the high-temperature rheological properties of emulsified asphalt mastics before and after rolling thin film oven test (RTFOT) ageing. Based on the principle of time–temperature equivalence and a viscoelasticity material model, the main curve of emulsified asphalt mastics under frequency scanning test is established, and the rheological properties of emulsified asphalt mastics in a wide frequency domain are analyzed. Finally, the grey entropy theory is used to quantitatively analyze the correlation between different high temperature performance evaluation indices of emulsified asphalt mastics. The results show that the RTFOT ageing process can significantly enhance the high temperature deformation resistance of emulsified asphalt residue and its mastics. The rutting factor (G*/sin δ) of emulsified asphalt mastics increases exponentially with the increase of F/B, while the phase angle is less affected. TCGP mastics and PC mastics have better high temperature performances than those of LP mastics. The most suitable range of F/B is 0.9~1.2 when TCGP is used as the filler, and 1.2~1.5 when PC or LP is used as the filler. Grey entropy correlation analysis shows that there is a good correlation between the two evaluation systems of the DSR test and the MSCR test, and both can evaluate the high-temperature performance of emulsified asphalt mastics.

Fatigue performance enhancement and high-temperature performance evaluation of asphalt treated base mixture

For hot climate areas with heavy traffic loads, the use of Asphalt Treated Base (ATB) requires higher fatigue and rutting resistance performance. To enhance the fatigue resistance performance of ATB mixture and evaluate the high-temperature performance, this study selected different kinds of binders, binder contents, and modifiers to explore the influencing factors of ATB mixture fatigue behavior using the four-point bending beam test. The results show that the fatigue life of ATB mixture is increased with lower penetration grade, larger aggregate sizes, or higher asphalt-aggregate ratio. High modulus ATB mixture has better fatigue and rutting resistance performance.

Rationality and Applicability of High-Temperature Performance Indexes for Polymer-Modified Asphalts

AbstractAt present, the rationality and applicability of various high-temperature performance evaluation indexes for polymer-modified asphalts have not been comprehensively explored. This study aim...

Study on Quantitative Characterization of Morphological Characteristics and High Temperature Performance Evaluation of Coarse Aggregate Based on Computer Vision

The morphological characteristics of aggregate include outline shape, angularity, and surface texture, which determine the mutual extrusion and friction between aggregates, and significantly affect the performance of asphalt pavement. At present, the research on the morphological characteristics of coarse aggregate is mainly focused on indoor visual identification technology (AIMS, XCT, etc.), in which the applicability of the proposed aggregate shape characterization index is weak, and these instruments could not serve the practical engineering well. In this article, the Coarse Aggregate Morphological Identification System (CAMIS) is developed based on computer vision technology, and the system can recognize the shape features of aggregates above 2.36 mm particle size and carry out uninterrupted feeding and removal based on the mechanical arm system, which can realize large sample detection. Based on CAMIS aggregate identification system and laboratory tests (rutting test, dynamic modulus test, and penetration shear test), the shape identification and performance test of aggregate samples from construction site are carried out, and an aggregate performance evaluation index, CEI, suitable for high-temperature areas is proposed in combination with the improved response surface method. The processing parameters of vertical shaft impact aggregate crusher are optimized based on the CEI index, and the recommended processing parameters are verified by laboratory tests. The results show that the morphological characteristics of coarse aggregate affect the high temperature performance in order angularity, needle flake, axial coefficient, and convexity. The combination of processing parameters of vertical axis impact crusher is recommended to be of 45 m/s rotational speed, 3 t/h feed quantity, and 30% air intake. Verified by laboratory tests, the aggregate identification system CAMIS developed in this article and the proposed aggregate performance evaluation index, CEI, are highly reliable.

Evaluation of the terminal blend crumb rubber/SBS composite modified asphalt

Terminal Blend rubberized asphalt (TBRA) is a novel application of Crumb Rubber (CR) modified asphalt. Compared with traditional CR modified asphalt, TBRA has good storage stability with a lower viscosity. However, TBRA generally has inferior high temperature performance, thereby SBS polymer is usually incorporated for composite modification. This paper evaluates the performances of TB/SBS composite modified asphalt with various modification formulas. Different rubber contents and SBS polymer contents were considered. Low temperature performance grading test, thermal stress master curve and low temperature Semi-Circular Bend (SCB) test were conducted for low-temperature performance evaluation. Multiple Stress Creep and Recovery (MSCR) and Hamburg Wheel Tracking (HWT) test were conducted for high-temperature performance evaluation. The results show that a 2% SBS addition can enhance the rutting resistance and moisture resistance of TBRA mixture without impairing its low-temperature performances. But more SBS introduction is not putting much extra value. Also, it is observed that with the presence of chemically active SBS polymer, rubber molecules from TB process also take part in the polymer crosslinking networking and strengthen the mixture. Based on both performance evaluation and cost analysis, a 10%TB plus 2%SBS formula is recommended in this study.

High Temperature Performance of SBS and LM-S Modified Asphalt Mixtures by Triaxial Test

In order to study the high temperature performance of LM-S modified asphalt mixture and SBS modified asphalt mixture, repeated loading creep test was used to study the influence of temperature and deviatoric stress on the axial permanent deformation of the two kinds of asphalt mixture. At the same time, Permanent deformation, ε@5000, flow number FN and creep rate were select to evaluation of high temperature performance from different directions. The results show that the ε@5000 and creep rate are failed in the condition of high temperature and large deviatoric stress, so it hast widely practicable. The flow number FN is also limited by the conditions, which leads to the distortion of the flow number at lower temperature and smaller deviatoric stress so it is not easy to direct used as the evaluation index. Axial permanent deformation can reflect the permanent deformation in different cycles which is an excellent index to evaluate the high temperature performance of the two kinds of asphalt mixture, it is recommended to use axial permanent deformation to compare the LM-S modified asphalt mixture and SBS modified asphalt mixture The experimental results show that the axial permanent deformation of the LM-S modified asphalt mixture is always less than that of SBS modified asphalt mixture,it indicating that the high temperature rutting resistance of the LM-S modified asphalt mixture is better than that of SBS modified asphalt mixture.

Evaluation of High-Temperature Performance of Asphalt Mixtures Based on Climatic Conditions

The dynamic stability of a rutting test does not optimally reflect the high-temperature stability of asphalt mixtures. In this study, a rutting test was performed over a long duration (4 h) at different temperatures (40, 50, 60, 70 °C) for three asphalt mixtures, namely, matrix AC-16, SMA-16, and modified AC-16 asphalt mixtures. Subsequently, the temperature rutting rate was obtained after considering the annual temperature conditions of Guangdong and Beijing in China. Because the conditions of the rutting test were different from that of the actual pavement, the rut depth was calculated using a modified temperature rutting rate. This modification considered four factors: wheel trace distribution, temperature, pavement thickness, and loading rate. The calculation of the temperature rutting rate considered the climatic conditions and utilized the rutting deformation data from hour 1–4 of the rutting tests, during which the asphalt mixture was in a stable creep period. Thus, the high-temperature stability of the asphalt mixture was reflected more scientifically by the temperature rutting rate than the dynamic stability. The high-temperature rut-resistance of the asphalt mixture was found to improve significantly after the introduction of two additives (anti-rutting agent and lignin fiber). The modified formula for rut depth can realistically predict the annual rutting depth for three asphalt mixtures in a one-way driving pavement.

Effects of Gamma-Irradiated Recycled Low-Density Polyethylene on the Creep and Recovery Properties of Asphalt

To improve the performance of recycled low-density polyethylene (LDPER), this paper describes the polymer modification of bitumen with gamma-irradiated recycled low-density polyethylene (γ-LDPER). The effects of the γ-LDPER on bitumen were investigated by means of morphological and chemical analyses, including Fourier-transform infrared spectroscopy and multiple stress creep recovery (MSCR) test. The results showed that the surface of the LDPER treated by gamma beam irradiation led to the formation of free radicals and some functional groups that may contribute to the creation of strong chemical bonds between the polymer modifier and bitumen, thus improving the compatibility of the modified asphalt. With the increased use of γ-LDPER, the modified asphalt rutting resistance also increased. However, due to the high γ-LDPER content of the modified asphalt, undertaking the high-temperature performance evaluation of the applicability of MSCR deserves further study.

Gray relational entropy analysis of high temperature performance of bio-asphalt binder and its mixture

Most of the existing researches only focus on some performances of the bio-asphalt binders instead of the asphalt mixtures, and the relationship between the performance of bio-asphalt binder and the performance of the mixture has been rarely reported. To analyze the gray relational entropy of high temperature performance of bio-asphalt binder and mixture, the bio-asphalt modified by 1% SBS with the concentrations of 0% (50#), 5%, 10%, 15%, and 20% by the weight of bio-asphalt binder, respectively, was used in this study. The performance indexes of bio-asphalt binder were tested through the conventional performance test and Superpave test of asphalt. The correlation between the performance indexes of the asphalt binder and the dynamic stability of the mixture was studied through the gray relational entropy method. The results showed that the high temperature performance of bio-asphalt had a certain degree of reduction before RTFO with the incorporation of bio-oil. The binder test parameters showed different changes in the law with the changes of bio-oil content. The dynamic stability of bio-asphalt mixtures decreased with an increase in bio-oil content. The RTFO aging had a great influence on the entropy correlation between the performance indexes of the bio-asphalt binders and the dynamic stability of the mixture. The non-recoverable creep compliance of bio-asphalt with low content (1%) of SBS modifier was weakly correlated with the dynamic stability of the mixture. The dynamic viscosity of bio-asphalt and the dynamic stability of the mixture exhibited the highest gray entropy correlation, which could be used as the key index of high-temperature performance evaluation of bio-asphalt.

Laboratory Study on Properties of Diatomite and Basalt Fiber Compound Modified Asphalt Mastic

In order to improve the performance of asphalt mastic, some researchers have added diatomite or basalt fiber as a modifier to the asphalt mastic, and the results show that some properties of the asphalt mastic were improved. For the simultaneous addition of diatomite and basalt fiber, two kinds of modifier, compound modified asphalt mastic had not been reported; in this paper, thirteen groups of diatomite and basalt fiber (DBFCMAM) compound modified asphalt mastic with different content were prepared to study the performance. Softening point, cone penetration, viscosity, and DSR tests were conducted, for the high temperature performance evaluation of DBFCMAM, whereas force ductility and BBR tests were used in the low temperature performance study of the DBFCMAM. The results demonstrated that the high temperature performance of DBFCMAM was increased; moreover, the low temperature performance of DBFCMAM improved by diatomite and basalt fiber according to the results of the force ductility test; however, the conclusion of the BBR test data was inconsistent with the force ductility test. In summary, the high temperature and low temperature properties of DBFCMAM had been improved.

Modified repeated load tri-axial test for the high-temperature performance evaluation of HMA

A modified repeated load tri-axial (RLT) test, capable of simulating the lateral confinement and temperature gradient in real pavement, was developed to evaluate the high-temperature performance of asphalt mixture. Proper indenter size was determined to apply partial pressure to the specimen to produce varying lateral confining pressure. To generate temperature gradient of field pavement within the specimen, the side and bottom areas of the specimen were covered with thermal isolating materials so that only the surface transfers heat with the environment. This study then fabricated a three-layer mix as the specimen to examine the effectiveness of the modified RLT test. Testing elements include surface, middle and bottom mix types, binder types, temperatures as well as their interactive impacts. The flow number index, defined as strain/load cycle, is found to be able to differentiate the impacts of all the factors except for the surface layer mix. The developed test can readily utilise the current RLT test apparatus with minor modifications and better characterise the high-temperature performance of asphalt mix at the expense of additional specimen preparation work.

High temperature performance evaluation of bio-oil modified asphalt binders using the DSR and MSCR tests

The high temperature performance of bio-oil modified asphalt binders were evaluated using dynamic shear rheometer (DSR) and multiple stress creep recovery (MSCR) tests. Three types of bio-oils generated from waste woods were investigated: untreated bio-oil (UTB), treated bio-oil (TB) and polymer modified bio-oil (PMB). The control asphalt binder (PG58-28) was blended with 5% and 10% bio-oils to prepare bio-oil modified asphalt binders. Dynamic shear modulus (|G∗|) and phase angle (δ) as well as high temperature stability index (|G∗|/sinδ) were evaluated through the DSR test, while non-recoverable creep compliance (Jnr) and percent recovery were investigated using the MSCR test. Both the DSR and MSCR test results showed that the addition of the bio-oils improved the high temperature stability of asphalt binder with respect to higher |G∗|, lower δ, lower Jnr and higher percent recovery. In detail, with the increase of bio-oil percentage, asphalt high temperature performance was improved. The statistical analysis showed that such improvement was statistically significant. In terms of the comparison among the three types of bio-oils, it was found that results from the DSR and MSCR tests were slightly different. In the DSR test, the UTB modified binders showed slightly weaker high temperature stability than the TB and PMB modified binders, which was mainly due to the high moisture content in the UTB. Whereas in the MSCR test, the PMB modified binder showed slightly weaker high temperature stability than the UTB and TB modified binders, which was attributed to the low fraction of polymer (only 0.4% by weight) in the PMB modified binder. The slight inconsistency between the DSR and MSCR test was likely due to different loading magnitude and loading mode of the two tests. The study also suggests that it is preferable to conduct both the DSR and MSCR tests to obtain a comprehensive understanding of asphalt high temperature performance.