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Lijun Sun
The Key Laboratory of Road and Traffic Engineering, Ministry of Education, Shanghai 201804, China

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Journal article
Published: 29 August 2021 in Sustainability
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Predicting evacuation demand, including its generation and dissipation process, for urban rail transit systems under disruptions, such as line and station closure, often requires comprehensive historical data recorded under homogeneous situations. However, data under disruptions are hard to collect due to various reasons, which makes traditional methods impractical in evacuation demand prediction. To address this problem from the modeling perspective, we develop a data-efficient approach to predict evacuation demand for urban rail transit systems under disruptions. Our model-based approach mainly uses historical data obtained from the natural state, when no shocks take place. We first formulate the mathematical representation of the evacuation demand for every type of urban rail transit station. Input variables in this step are location features related to the station under the disruption, as well as an origin–destination matrix under the natural state. Then, based on these mathematical expressions, we develop a simulation system to imitate the spatio-temporal evolution of evacuation demand within the whole network under disruptions. The transport capacity drop under disruptions is used to describe the disruption situation. Several typical scenarios from the Shanghai metro network are used as examples to implement the proposed method. The results show that our method is able to predict the generation and dissipation processes of evacuation demand, as well model how severely stations will be affected by given disruptions. One general observation we draw from the results is that the most vulnerable stations under disruption, where the locations peak evacuation demand occurs, are mainly turn-back stations, closed stations, and the transfer stations near closed stations. This paper provides new insight into evacuation demand prediction under disruptions. It could be used by transport authorities to better respond to the urban rail transit system disruption.

ACS Style

Xiaoqing Dai; Han Qiu; Lijun Sun. A Data-Efficient Approach for Evacuation Demand Generation and Dissipation Prediction in Urban Rail Transit System. Sustainability 2021, 13, 9692 .

AMA Style

Xiaoqing Dai, Han Qiu, Lijun Sun. A Data-Efficient Approach for Evacuation Demand Generation and Dissipation Prediction in Urban Rail Transit System. Sustainability. 2021; 13 (17):9692.

Chicago/Turabian Style

Xiaoqing Dai; Han Qiu; Lijun Sun. 2021. "A Data-Efficient Approach for Evacuation Demand Generation and Dissipation Prediction in Urban Rail Transit System." Sustainability 13, no. 17: 9692.

Journal article
Published: 16 August 2021 in Construction and Building Materials
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Due to the remarkable ecological and economic benefits, more and more attention has been paid to the technology of reclaimed asphalt pavement (RAP). Currently, the potential risks of thermal and fatigue cracking still restrict the large-scale application of recycled materials. This study regards the number of design gyrations (Ndes) as a variable and uses a lower Ndes to design the recycled HMAs with higher RAP percentage, which attempts to compensate for the cracking problems by increasing the asphalt content. Five groups containing RAP content various from 0% to 80% were designed. Combined with the statistical analysis (i.e., Tukey pairwise comparison), the high-/low- temperature properties, fatigue life, dynamic modulus, and environmental impacts of this method were evaluated. It can be seen that recycled HMAs actually do not require as high compaction effort as the unrecycled ones (0% RAP). For the recycled HMAs containing 80% RAP, the Ndes of 60 cycles is sufficient for them to achieve the similar high-temperature resistance as the unrecycled ones (using Ndes = 100 cycles). In addition, the results indicate that this method can effectively improve the low-temperature and fatigue properties of recycled HMAs, even at a higher RAP percentage. Specifically, with the decrease of Ndes by 12%, the fracture energy and fatigue life of recycled HMAs can increase by almost 3–18% and 10–20%, respectively. Moreover, the method also has considerable effects on the environment. As the content of RAP increases by 20%, the energy consumption and CO2 emission can reduce by approximately 7–10% and 8–10%, respectively.

ACS Style

Yining Zhang; Huailei Cheng; Lijun Sun. Performance-based design of recycled hot-mix asphalt (HMA) incorporating compaction effort variable. Construction and Building Materials 2021, 303, 124277 .

AMA Style

Yining Zhang, Huailei Cheng, Lijun Sun. Performance-based design of recycled hot-mix asphalt (HMA) incorporating compaction effort variable. Construction and Building Materials. 2021; 303 ():124277.

Chicago/Turabian Style

Yining Zhang; Huailei Cheng; Lijun Sun. 2021. "Performance-based design of recycled hot-mix asphalt (HMA) incorporating compaction effort variable." Construction and Building Materials 303, no. : 124277.

Journal article
Published: 17 June 2021 in International Journal of Fatigue
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Fatigue cracking is one of the main distress modes of highway asphalt pavements. In laboratory fatigue tests, haversine or sinusoidal loading waves are commonly applied to characterize the fatigue performance of asphalt mixture samples. The strain wave in field asphalt layer under a moving axle load, however, is noticeably different from the haversine or sinusoidal wave. This research compared the fatigue behaviours of compacted asphalt mixture samples under actual strain waves and the commonly used haversine wave. Two types of actual strain waves induced by the single axle and tandem axle of vehicles were included for analysis. It is found that the fatigue lives of asphalt mixture samples subjected to the single-axle wave are obviously higher than those subjected to haversine wave, while the tandem–axle wave leads to the lowest fatigue life. The changing rates of stiffness, phase angle, and dissipated energy with loading cycles for the mixture samples under single-axle wave are all the lowest, while those under tandem-axle wave are all the highest. This helps explain the discrepancies in the samples’ fatigue lives under different loading waves. The above findings suggest that it is necessary to test asphalt mixture samples using loading waves that simulate the actual ones in the field (i.e., single-axle wave and tandem-axle wave) to improve the reliability of fatigue life prediction of asphalt pavements. In addition, this research reveals that three dissipated-energy-based indicators, namely initial dissipated energy, cumulative dissipated energy and plateau value, all generate a unique relationship with the sample’s fatigue life. The relationship is independent of loading wave type and strain level.

ACS Style

Huailei Cheng; Lijun Sun; Yuhong Wang; Xingyu Chen. Effects of actual loading waveforms on the fatigue behaviours of asphalt mixtures. International Journal of Fatigue 2021, 151, 106386 .

AMA Style

Huailei Cheng, Lijun Sun, Yuhong Wang, Xingyu Chen. Effects of actual loading waveforms on the fatigue behaviours of asphalt mixtures. International Journal of Fatigue. 2021; 151 ():106386.

Chicago/Turabian Style

Huailei Cheng; Lijun Sun; Yuhong Wang; Xingyu Chen. 2021. "Effects of actual loading waveforms on the fatigue behaviours of asphalt mixtures." International Journal of Fatigue 151, no. : 106386.

Research article
Published: 19 May 2021 in Road Materials and Pavement Design
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In this study, dynamic moduli of asphalt mixtures under uniaxial compression (UC), indirect tension (IDT) and four-point bending (4PB) loading modes were tested and incorporated in the MEPDG procedure to predict the pavement responses. The field responses from a full-scale asphalt pavement were used to evaluate the prediction accuracies of three types of moduli. It was found that the current MEPDG procedure using UC modulus underestimates the strain responses of the pavement. Alternatively, the use of 4PB modulus in the MEPDG generates accurate strain predictions at the intermediate temperatures, but not at high temperatures. The combined use of UC modulus and the adjusted loading frequency, f′=1/(2πt) also generates accurate strain predictions at the intermediate temperatures. At high temperatures, the combined use of the 4PB modulus and f′=1/(2πt) was found to generate the most accurate prediction results. Accurate prediction of asphalt pavement responses is apparently dependent on the proper selection of modulus type and loading frequency.

ACS Style

Huailei Cheng; Yuhong Wang; Liping Liu; Lijun Sun. Effects of using different dynamic moduli on predicted asphalt pavement responses in mechanistic pavement design. Road Materials and Pavement Design 2021, 1 -17.

AMA Style

Huailei Cheng, Yuhong Wang, Liping Liu, Lijun Sun. Effects of using different dynamic moduli on predicted asphalt pavement responses in mechanistic pavement design. Road Materials and Pavement Design. 2021; ():1-17.

Chicago/Turabian Style

Huailei Cheng; Yuhong Wang; Liping Liu; Lijun Sun. 2021. "Effects of using different dynamic moduli on predicted asphalt pavement responses in mechanistic pavement design." Road Materials and Pavement Design , no. : 1-17.

Review
Published: 16 April 2021 in International Journal of Transportation Science and Technology
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It is widely proposed that Mars will be the next destination for human to expand colonization. However, building up a habitat requires collective work from multiple disciplinaries of which engineering is an indispensable part. Similar to infrastructure construction on the earth, the technical issues of raw material, space construction technologies has to be addressed before human inhabitation. Based on the history of Mars exploration missions and a series of current Mars exploration results, this paper introduces the environment conditions on Mars, reviews the research of the in-situ resources which can be further utilized for infrastructure construction on Mars and proposes feasible infrastructure construction technologies. This paper provides an overview of in-situ construction material resources, possible construction methods and requirements for materials in extreme environment, which can be a valuable reference for future Mars exploration and possible infrastructure construction on the Mars.

ACS Style

Jiawen Liu; Hui Li; Lijun Sun; Zhongyin Guo; John Harvey; Haizhu Lu; Ing Jia. In-situ resources for infrastructure construction on Mars: A review. International Journal of Transportation Science and Technology 2021, 1 .

AMA Style

Jiawen Liu, Hui Li, Lijun Sun, Zhongyin Guo, John Harvey, Haizhu Lu, Ing Jia. In-situ resources for infrastructure construction on Mars: A review. International Journal of Transportation Science and Technology. 2021; ():1.

Chicago/Turabian Style

Jiawen Liu; Hui Li; Lijun Sun; Zhongyin Guo; John Harvey; Haizhu Lu; Ing Jia. 2021. "In-situ resources for infrastructure construction on Mars: A review." International Journal of Transportation Science and Technology , no. : 1.

Journal article
Published: 06 March 2021 in Journal of Cleaner Production
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Solid wastes have been widely applied in porous asphalt pavement, but some of them may contain pollutants. Whether their leachate during rainfall events poses a threat to nearby watersheds has not received enough attention. Based on the laboratory rainfall and infiltrate test, this study evaluated the leachate risks of fine solid wastes in porous asphalt mixture (PA). Based on the runoff pollution characteristics in Shanghai, China, the purification performance of PA with diatomite filler was explored. The results showed that a small amount of Al and Fe in solid waste fillers might infiltrate during intensive rainfall. The diatomite filler could improve pollutants removal rates via physical filtration and selective chemical adsorption effects. The correlations between rainfall characteristics and the removal rates were further developed, which indicated the increase of rainfall time and intensity adversely affected the removal rates. The composition of PA for different runoff pollution characteristics was proposed as well.

ACS Style

Jiawen Liu; Hui Li; Lijun Sun; Hengji Zhang; Ning Xie; Yu Tian; Ming Jia; Kaimin Fu; Bo Yu; YaoTing Zhu. Leachate risks of fine solid wastes in porous asphalt pavement and runoff purification effects of diatomite filler. Journal of Cleaner Production 2021, 297, 126623 .

AMA Style

Jiawen Liu, Hui Li, Lijun Sun, Hengji Zhang, Ning Xie, Yu Tian, Ming Jia, Kaimin Fu, Bo Yu, YaoTing Zhu. Leachate risks of fine solid wastes in porous asphalt pavement and runoff purification effects of diatomite filler. Journal of Cleaner Production. 2021; 297 ():126623.

Chicago/Turabian Style

Jiawen Liu; Hui Li; Lijun Sun; Hengji Zhang; Ning Xie; Yu Tian; Ming Jia; Kaimin Fu; Bo Yu; YaoTing Zhu. 2021. "Leachate risks of fine solid wastes in porous asphalt pavement and runoff purification effects of diatomite filler." Journal of Cleaner Production 297, no. : 126623.

Journal article
Published: 30 January 2021 in Construction and Building Materials
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The current mix design method that is established based on the volumetric properties works well for conventional hot-mixed asphalt (HMA), but does not satisfy the design of hard HMAs. Hard HMAs refer to the mixtures designed using hard asphalt binder whose penetration is less than the conventional one (70#). Increasing asphalt content is regarded to be an effective way to design hard HMAs and keeps them away from thermal cracking problem. Therefore, this research explored the suitable volumetric criteria for designing hard HMAs. The principle of establishing the volumetric criteria is to ensure hard HMAs can achieve the equivalent performance as conventional ones. Eleven groups of AC16 containing three penetration grades of asphalt binders (70#, 50#, and 30#) were designed, and the volumetric properties, uniaxial penetration shear test (UPST), low-temperature bending test (LTBT) and four-point bending test (4PBT) were then conducted. Based on experiment data, two key volumetric criteria of AFT and VMA are established for hard HMAs. It can be seen that when the ranges of AFT maintain within the 10–11.2 µm and 12.9–13.4 µm, respectively, the 50# and 30# hard HMAs can reach the equivalent high- and low- temperature performance as 70# conventional HMAs. Correspondingly, the ranges of criteria in VMA for 50# and 30# hard HMAs need to maintain within 15.6–17.5% and 17.6–19.5%, respectively. Overall, a higher value of volumetric criteria is required for designing hard HMA compared with conventional one. In addition, the results of 4PBT indicate that hard HMAs can also exhibit good fatigue resistance when they are designed within these criteria.

ACS Style

Yining Zhang; Huailei Cheng; Lijun Sun; Liping Liu; Yue Hu. Determination of volumetric criteria for designing hard asphalt mixture. Construction and Building Materials 2021, 278, 122243 .

AMA Style

Yining Zhang, Huailei Cheng, Lijun Sun, Liping Liu, Yue Hu. Determination of volumetric criteria for designing hard asphalt mixture. Construction and Building Materials. 2021; 278 ():122243.

Chicago/Turabian Style

Yining Zhang; Huailei Cheng; Lijun Sun; Liping Liu; Yue Hu. 2021. "Determination of volumetric criteria for designing hard asphalt mixture." Construction and Building Materials 278, no. : 122243.

Journal article
Published: 19 January 2021 in Construction and Building Materials
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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%.

ACS Style

Haobai Zhong; Weidong Huang; Chuanqi Yan; Yuan Zhang; Quan Lv; Lijun Sun; Liyuan Liu. Investigating binder aging during hot in-place recycling (HIR) of asphalt pavement. Construction and Building Materials 2021, 276, 122188 .

AMA Style

Haobai Zhong, Weidong Huang, Chuanqi Yan, Yuan Zhang, Quan Lv, Lijun Sun, Liyuan Liu. Investigating binder aging during hot in-place recycling (HIR) of asphalt pavement. Construction and Building Materials. 2021; 276 ():122188.

Chicago/Turabian Style

Haobai Zhong; Weidong Huang; Chuanqi Yan; Yuan Zhang; Quan Lv; Lijun Sun; Liyuan Liu. 2021. "Investigating binder aging during hot in-place recycling (HIR) of asphalt pavement." Construction and Building Materials 276, no. : 122188.

Journal article
Published: 04 December 2020 in Construction and Building Materials
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The laboratory fatigue test for the asphalt mixture is generally conducted at the intermediate temperatures (10 °C to 20 °C). Some research findings reveal that fatigue cracking may also appear in the asphalt layer at higher temperatures. Motivated by these findings, the present research investigated and compared the fatigue behaviours of the asphalt mixture at a wide range of temperatures (15 °C to 40 °C with an interval of 5 ℃) in four-point bending (4 PB) and indirect tensile (IDT) fatigue tests. The dense-graded asphalt mixtures (AC-13) using neat asphalt binder and Styrene-butadiene-styrene (SBS) modified asphalt binder are applied for evaluation. It is found that a uniform law exists for the stiffness evolution of the asphalt mixture in the fatigue test: as the stiffness of the asphalt mixture declined to about 70% of its initial stiffness, the asphalt mixture starts to experience the stable fatigue damage accumulation stage. The temperature affects the fatigue life of the asphalt mixture oppositely in the 4 PB and IDT tests. In the 4 PB test, the rising temperature causes an increase in the fatigue life of the mixture. However, in the IDT test, the fatigue life of the mixture decreases obviously with the increase of temperature. The model Nf=a(1/F)becT is proposed and developed to describe the relationships among fatigue life (Nf), temperature (T) and stress/strain level (F) of asphalt mixture in 4 PB and IDT tests. The developed models provide reference data for evaluating the fatigue resistance of the asphalt layer under various temperature and strain/stress conditions.

ACS Style

Huailei Cheng; Jianing Liu; Lijun Sun; Liping Liu; Yining Zhang. Fatigue behaviours of asphalt mixture at different temperatures in four-point bending and indirect tensile fatigue tests. Construction and Building Materials 2020, 273, 121675 .

AMA Style

Huailei Cheng, Jianing Liu, Lijun Sun, Liping Liu, Yining Zhang. Fatigue behaviours of asphalt mixture at different temperatures in four-point bending and indirect tensile fatigue tests. Construction and Building Materials. 2020; 273 ():121675.

Chicago/Turabian Style

Huailei Cheng; Jianing Liu; Lijun Sun; Liping Liu; Yining Zhang. 2020. "Fatigue behaviours of asphalt mixture at different temperatures in four-point bending and indirect tensile fatigue tests." Construction and Building Materials 273, no. : 121675.

Conference paper
Published: 26 August 2020 in Lecture Notes in Civil Engineering
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The modulus of asphalt mixture is traditionally measured from the laboratory dynamic modulus test. However, different laboratory test methods often lead to obviously different test results. To evaluate the moduli of asphalt mixtures as constructed in field pavements, this study back-calculated the moduli of the pavement layers, based on measured strain data in Accelerated Pavement Testing (APT). Field tests were conducted to measure strains at different locations of the built pavement section at different temperatures and wheel motion speed. The loading frequencies of the asphalt layer subject to different motion speeds were calculated based on the duration of measured strain pulses. Subsequently, the relationship between the motion speed and the loading frequency was established. An finite element (FE) model of the pavement section was created, which was used to back-calculate the moduli of asphalt pavement layers using the measured strain data. Based on the back-calculation results at different loading conditions, the master curve of the field asphalt layer was determined. This master curve was further used to compare with that obtained from laboratory uniaxial compressive test. The relationship between the field and laboratory moduli was determined to be ELaboratory= 1.298EField.

ACS Style

Huailei Cheng; Yuhong Wang; Liping Liu; Lijun Sun; Yue Hu; Yi Li. Back-Calculation of the Moduli of Asphalt Pavement Layer Using Accelerated Pavement Testing Data. Lecture Notes in Civil Engineering 2020, 379 -388.

AMA Style

Huailei Cheng, Yuhong Wang, Liping Liu, Lijun Sun, Yue Hu, Yi Li. Back-Calculation of the Moduli of Asphalt Pavement Layer Using Accelerated Pavement Testing Data. Lecture Notes in Civil Engineering. 2020; ():379-388.

Chicago/Turabian Style

Huailei Cheng; Yuhong Wang; Liping Liu; Lijun Sun; Yue Hu; Yi Li. 2020. "Back-Calculation of the Moduli of Asphalt Pavement Layer Using Accelerated Pavement Testing Data." Lecture Notes in Civil Engineering , no. : 379-388.

Conference paper
Published: 26 August 2020 in Lecture Notes in Civil Engineering
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Asphalt concrete (AC) modulus reduction caused by repeated axle loading significantly affects pavement long-term performance; including when built on a semi-rigid layer. However, quantifying this effect is challenging. The primary objective of this paper was to monitor and evaluate modulus reduction and fatigue damage accumulation at various AC depths utilizing data obtained from two semi-rigid pavement sections. During loading, a non-destructive method, portable seismic pavement analyzer (PSPA), was used to predict the modulus ratio. PSPA test results show that the damage is nonlinear with respect to the loading passes. Also, depth and AC thickness can influence the development of damage. A developed model showed that it could predict the aforementioned nonlinear relationship. The model parameters can be used to identify the damage level at various AC depths. Unexpected compared with previous understanding, the damage in AC layers was found to increased first, then decreased, and finally increased with the depth. Since PSPA is cheap, portable, and easy to apply, this method to identify the damage level in AC layers is proven to be applicable and practical.

ACS Style

Yi Li; Jiahao Li; Liping Liu; Lijun Sun. Accelerated Fatigue Damage Profile of Asphalt Concrete Placed on Semi-rigid Layer. Lecture Notes in Civil Engineering 2020, 90 -99.

AMA Style

Yi Li, Jiahao Li, Liping Liu, Lijun Sun. Accelerated Fatigue Damage Profile of Asphalt Concrete Placed on Semi-rigid Layer. Lecture Notes in Civil Engineering. 2020; ():90-99.

Chicago/Turabian Style

Yi Li; Jiahao Li; Liping Liu; Lijun Sun. 2020. "Accelerated Fatigue Damage Profile of Asphalt Concrete Placed on Semi-rigid Layer." Lecture Notes in Civil Engineering , no. : 90-99.

Journal article
Published: 22 May 2020 in Construction and Building Materials
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Healing behavior of asphalt is crucial to the engineering performance of asphalt pavement and helps with extended service life. Therefore, the healing behavior of asphalt material has been widely investigated by extensive researchers. However, most studies focused on the evolution in asphalt modulus/stiffness and less attention was paid to the healing behavior in asphalt bonding properties. Even fewer researchers have discussed this topic at an asphalt mastic level. This study aims to evaluate the bonding healing behavior between the asphalt/aggregate interface using the bitumen bonding strength (BBS) test. Both asphalt binder and asphalt mastic were investigated. Numerous variables including healing time, healing temperature, presence of water, polymer modification and multiple healing cycles were discussed. Additionally, non-destructive X-ray Computed Tomography (CT) scan was conducted to visually confirm the macro healing process inside the asphalt material. Results suggest that bonding healing is a long-stand behavior, but after multiple fracture-healing cycles, the ultimate healing capability is quite low, especially for Styrene-Butadiene-Styrene polymer modified asphalt. Mastic samples exhibited improved healing properties than binder samples at all healing conditions. At a reasonable high curing temperature of 40 °C, base asphalt mastic shows nearly 100% recovery rate. Based on CT scan test, water and polymer modification weakens the asphalt healing ability while extended healing time and increased temperature is beneficial.

ACS Style

Quan Lv; Weidong Huang; Mao Zheng; Gengren Hao; Chuanqi Yan; Lijun Sun. Investigating the asphalt binder/mastic bonding healing behavior using bitumen bonding strength test and X-ray Computed Tomography scan. Construction and Building Materials 2020, 257, 119504 .

AMA Style

Quan Lv, Weidong Huang, Mao Zheng, Gengren Hao, Chuanqi Yan, Lijun Sun. Investigating the asphalt binder/mastic bonding healing behavior using bitumen bonding strength test and X-ray Computed Tomography scan. Construction and Building Materials. 2020; 257 ():119504.

Chicago/Turabian Style

Quan Lv; Weidong Huang; Mao Zheng; Gengren Hao; Chuanqi Yan; Lijun Sun. 2020. "Investigating the asphalt binder/mastic bonding healing behavior using bitumen bonding strength test and X-ray Computed Tomography scan." Construction and Building Materials 257, no. : 119504.

Journal article
Published: 15 May 2020 in Transportation Research Part F: Traffic Psychology and Behaviour
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The inertia effects stemmed from repeated past behavior have been investigated by both psychology and transportation studies because of its bearing on explaining human mobility and forecasting travel demand. However, the existing literature from psychology does not strictly control potential endogeneity due to ignorance of detailed level-of-service (LOS) variables of alternatives and rational preference in the analysis. Quantitative transportation studies are insufficient in providing explicit behavior mechanisms. This paper aims to fill the gaps by empirically examining the effects of irrational psychological inertia in mode shift behavior with controlling potential endogeneity. A specific-designed comparison experiment is conducted to demonstrate the existence of psychological inertia in mode shift behavior. The effects of dominance in LOS variables and rational preference towards a certain transport mode are controlled to eliminate potential endogeneity in the analysis. The results demonstrate that after controlling the above-mentioned endogeneity, both car and metro users show significantly and substantially larger predilections to previously used transport mode in mode shift scenarios without overturning travel contexts than those in new context mode choice scenarios with noticeable changes in travel contexts. The results support that psychological inertia plays a significant role in mode shift behavior after controlling potential endogeneity. Moreover, this study utilizes hybrid choice modeling to quantitatively measure the effect of psychological inertia. The relationships between travelers’ characteristics and strength of psychological inertia are analyzed as well to shed light on heterogeneity in the strength of psychological inertia. The findings provide solid evidence of psychological inertia in mode shift behavior by a novel method and provide an approach to measure the quantitative effects of psychological inertia along with empirical studies.

ACS Style

Kun Gao; Ying Yang; Lijun Sun; Xiaobo Qu. Revealing psychological inertia in mode shift behavior and its quantitative influences on commuting trips. Transportation Research Part F: Traffic Psychology and Behaviour 2020, 71, 272 -287.

AMA Style

Kun Gao, Ying Yang, Lijun Sun, Xiaobo Qu. Revealing psychological inertia in mode shift behavior and its quantitative influences on commuting trips. Transportation Research Part F: Traffic Psychology and Behaviour. 2020; 71 ():272-287.

Chicago/Turabian Style

Kun Gao; Ying Yang; Lijun Sun; Xiaobo Qu. 2020. "Revealing psychological inertia in mode shift behavior and its quantitative influences on commuting trips." Transportation Research Part F: Traffic Psychology and Behaviour 71, no. : 272-287.

Journal article
Published: 30 April 2020 in Chinese Science Bulletin
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The backcalculated structural moduli of asphalt pavement using the falling weight deflectomer (FWD) deflection basin data has been increasingly used for evaluating the bearing capacity of non-destructive pavement structures. The current backcalculation methods can be divided into 2 categories, i.e., one algorithm based on deflection basin matching and the other algorithm based on deflection basin law. The principle of the former algorithm is to find a set of structural layer moduli so that the theoretical deflection and the measured deflection have the highest matching degree, and the later algorithm uses some regular and special points according to the law of the deflection basin affected by the structural parameters to backcalculate layer moduli. Research has shown that the former algorithm has a problem in whether there is a unique solution and the inversion efficiency. While the basin law algorithm is able to generate a unique solution, which makes it more suitable for engineering applications. However, the identity points used in the current basin law algorithm were determined based on the theoretically calculated FWD deflection basins. The accuracy of these identity points needs to be further validated using the field measured FWD data. Therefore, in order to determine the optimal positions of the identity points accurately, this paper analyzed the law of backcalculated moduli of pavement structure based on the measured layer-by-layer deflection basins of different pavement structures. First of all, the influence of different identity points on the backcalculated base moduli was investigated using the deflection data from the full scale testing track of RIOH. Then, the optimal positions of the identity points were determined, based on the principle of the consistency of the backcalculated base modulus using the measured deflection basin data, which means that the backcalculated modulus values of base layers should be almost the same. Finally, the accuracy of the optimization identity point method was verified by independent deflection data. The results indicated that the positions of identity points had significant effects on the backcalculated moduli for the base layer. When the position of the base identity point was unchanged, the variability of the backcalculated base modulus tended to decrease first and then increase as the position of the surface identity points as far away from the load center. And according to the deflection data from the full scale testing track of RIOH, we concluded that, for the two-layers asphalt pavement, when the optimal position of the identity point was 30 cm far from the load center while the positions for three-layers asphalt pavement were 0 and 60 cm away from the load center, the backcalculated base modulus based on layer-by-layer deflection data had the best consistency. Based on the inversion analysis of the independent deflection data, the accuracy of the position of the identity points determined in this study was verified. The verification results showed that the modified method proposed in this study could be used to accurately backcalculate the modulus of the pavement structure layer in other engineering, and the method was highly applicable. At the same time, the method proposed in this study had stable results and low variability, which can meet the needs of engineering.

ACS Style

Yue Hu; Guoshuai Zang; Lijun Sun; Liping Liu; Huailei Cheng. Determination of optimal identity points for backcalculating the structural layer moduli of asphalt pavement. Chinese Science Bulletin 2020, 65, 3287 -3297.

AMA Style

Yue Hu, Guoshuai Zang, Lijun Sun, Liping Liu, Huailei Cheng. Determination of optimal identity points for backcalculating the structural layer moduli of asphalt pavement. Chinese Science Bulletin. 2020; 65 (30):3287-3297.

Chicago/Turabian Style

Yue Hu; Guoshuai Zang; Lijun Sun; Liping Liu; Huailei Cheng. 2020. "Determination of optimal identity points for backcalculating the structural layer moduli of asphalt pavement." Chinese Science Bulletin 65, no. 30: 3287-3297.

Journal article
Published: 28 April 2020 in Applied Sciences
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Aggregate gradation and asphalt type are traditional variables that affects mix design of Hot-Mix Asphalt (HMA). Recently, the number of design gyrations (Ndes) has been increasingly accepted as another variable parameter during the design process. Due to the growing shortage of high-quality raw materials, it is necessary to make full use of the combined roles between these design parameters, instead of solely relying on their individual effect, to improve the HMA properties. Therefore, this study comprehensively explored the effect of aggregate gradation, Ndes, and asphalt type on the performance of HMAs. Seven different combinations of aggregate gradation, Ndes, and asphalt type were evaluated. The volumetric indicators, uniaxial penetration shear test (UPST), unconfined compression test (UCT), low-temperature bending test (LBT), four-point bending test (FPBT), and dynamic modulus test (DMT) were used to assess the performance of HMAs designed by various parameter combinations. It was found that the contribution of adopting harder asphalt binder was able to make up for the high-temperature resistance loss caused by lower Ndes or coarser gradation. The dynamic modulus exhibited the similar phenomenon. By contrast, the harder asphalt binder led to the worse tenacity of HMAs at low temperature; however, the tenacity can be restored through using lower Ndes or coarser gradation by increasing asphalt content. In addition, the fatigue life of HMAs went up significantly by about 36 ~ 41%, when both Ndes and asphalt penetration grade decreased to one lower level.

ACS Style

Yining Zhang; Lijun Sun; Huailei Cheng. Laboratory Performance Evaluation of Hot-Mix Asphalt Mixtures with Different Design Parameters. Applied Sciences 2020, 10, 3038 .

AMA Style

Yining Zhang, Lijun Sun, Huailei Cheng. Laboratory Performance Evaluation of Hot-Mix Asphalt Mixtures with Different Design Parameters. Applied Sciences. 2020; 10 (9):3038.

Chicago/Turabian Style

Yining Zhang; Lijun Sun; Huailei Cheng. 2020. "Laboratory Performance Evaluation of Hot-Mix Asphalt Mixtures with Different Design Parameters." Applied Sciences 10, no. 9: 3038.

Journal article
Published: 23 April 2020 in Construction and Building Materials
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Due to potential thermal cracking risks, marginal hard asphalt has not been widely used in China. A design method for hard asphalt under lower compaction levels was adopted in the present study with the aim of compensating for low-temperature cracking problems by increasing the asphalt content; simultaneously, the rutting resistance can still be maintained due to the high stiffness of hard asphalt itself. Four groups of asphalt, i.e. a control group (70# asphalt under Ndes = 75); two experimental groups (30# and 50# asphalt under Ndes = 50); and an analysis group (70# asphalt under Ndes = 50), were designed to evaluate the performance. Based on the experimental results, the conventional and this design method using 50# hard asphalt showed almost the same high- and low-temperature resistance. It is noteworthy that this method exhibited better fatigue resistance and increased fatigue life by approximately 1.6 times. In addition, this method also showed a larger dynamic modulus, especially under the traffic conditions of low frequency or high temperature. These results may indicate that a cheap marginal hard asphalt mixture under less compaction energy could achieve an even better performance than the conventional asphalt.

ACS Style

Yining Zhang; Lijun Sun; Liping Liu. Performance-based design of hard asphalt mixtures based on different compaction effort variable. Construction and Building Materials 2020, 254, 119240 .

AMA Style

Yining Zhang, Lijun Sun, Liping Liu. Performance-based design of hard asphalt mixtures based on different compaction effort variable. Construction and Building Materials. 2020; 254 ():119240.

Chicago/Turabian Style

Yining Zhang; Lijun Sun; Liping Liu. 2020. "Performance-based design of hard asphalt mixtures based on different compaction effort variable." Construction and Building Materials 254, no. : 119240.

Journal article
Published: 27 February 2020 in Construction and Building Materials
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The asphalt-based pavement performance evaluation includes the derivation of the dynamic moduli and loading frequencies of pavement layers under various traffic- and climatic-induced loading conditions. The traffic-induced strain pulses and loading frequencies of commonly used (semi-rigid, flexible, and steel deck) asphalt pavements were experimentally determined by vehicular loading field tests with embedded strain gauges for different axle loads, motion speeds, and temperatures. It was found that the axle load values had no noticeable effect on the pavement loading frequency, which was mainly controlled by the vehicular motion speed. The transverse frequencies were found to be higher than longitudinal ones, while the distributions of loading frequencies by pavement depth differed for three pavements under study. The frequency values at temperatures over 35 °C exceeded those at lower temperatures, while in the temperature range from 4 to 31 °C, the motion speed vs. loading frequency relations for three pavements were nearly identical. The loading frequency f increased approximately linearly with the motion speed V, according to the unified fitting equation for three types of pavements under study, namely f = 0.127 × V. This unified equation was further proved valid to predict the dynamic modulus properties of field asphalt pavement layers. Moreover, several previous prediction models for loading frequency, including the Brown model, Ullidtz model, MEPDG procedure and Ulloa model, were compared to the results in this study. These previous models were found to overestimate the loading frequencies within the asphalt layer. The prediction errors of the Brown model and the Ullidtz model were pronounced. The loading frequencies calculated by the MEPDG procedure and the Ulloa model need to be modified by dividing 2.8 and 1.7, respectively.

ACS Style

Huailei Cheng; Liping Liu; Lijun Sun; Yi Li; Yue Hu. Comparative analysis of strain-pulse-based loading frequencies for three types of asphalt pavements via field tests with moving truck axle loading. Construction and Building Materials 2020, 247, 118519 .

AMA Style

Huailei Cheng, Liping Liu, Lijun Sun, Yi Li, Yue Hu. Comparative analysis of strain-pulse-based loading frequencies for three types of asphalt pavements via field tests with moving truck axle loading. Construction and Building Materials. 2020; 247 ():118519.

Chicago/Turabian Style

Huailei Cheng; Liping Liu; Lijun Sun; Yi Li; Yue Hu. 2020. "Comparative analysis of strain-pulse-based loading frequencies for three types of asphalt pavements via field tests with moving truck axle loading." Construction and Building Materials 247, no. : 118519.

Articles
Published: 11 February 2020 in International Journal of Pavement Engineering
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The fatigue properties of the asphalt pavement layer are influenced significantly by different strain levels and temperatures. This research investigated the critical fatigue position within the asphalt pavement layer considering the couple effects of strain levels and temperatures. Firstly, field tests were conducted to measure the typical temperature distribution of the asphalt pavement layer. Secondly, laboratory four-point beam fatigue test and dynamic modulus test were applied to evaluate the fatigue life and the dynamic modulus of the asphalt mixture, respectively. Based on the results of field and laboratory tests, the distributions of strain and fatigue damage within the asphalt layer at different temperature conditions were calculated. It was found that the fatigue life of asphalt mixture decreased with the rising strain level but increased with the rising temperature. The critical fatigue position in the flexible pavement changed from 5 to 20 cm when the pavement temperature condition varied from high to medium/low. In terms of the semi-rigid pavement, this position varied between 6 and 12 cm at different temperature conditions. In addition, the fatigue damage within the semi-rigid pavement at high temperature was found to be as noticeable as that at medium/low temperatures. Thus, the fatigue properties of the asphalt layer at higher temperatures need to be carefully evaluated as well.

ACS Style

Huailei Cheng; Jianing Liu; Lijun Sun; Liping Liu. Critical position of fatigue damage within asphalt pavement considering temperature and strain distribution. International Journal of Pavement Engineering 2020, 1 -12.

AMA Style

Huailei Cheng, Jianing Liu, Lijun Sun, Liping Liu. Critical position of fatigue damage within asphalt pavement considering temperature and strain distribution. International Journal of Pavement Engineering. 2020; ():1-12.

Chicago/Turabian Style

Huailei Cheng; Jianing Liu; Lijun Sun; Liping Liu. 2020. "Critical position of fatigue damage within asphalt pavement considering temperature and strain distribution." International Journal of Pavement Engineering , no. : 1-12.

Journal article
Published: 23 January 2020 in Sustainability
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The dockless bike-sharing (DLBS) system serves as a link between metro stations and travelers’ destinations (or originations). This paper aims to uncover spatio-temporal usage patterns of dockless bike-sharing service linking to metro stations for supporting scientific planning and management of the dockless bike-sharing system. A powerful visualization tool was used to analyze the differences in usage patterns in workdays and weekends. The travel distance distributions of using dockless bike-sharing near metro stations were investigated to shed light on the service area of the dockless bike-sharing system. Agglomerative hierarchical clustering was applied to analyze differences in usage patterns of metro stations located in different areas. The results show that the usage patterns of dockless bike-sharing on weekends are different from those on workdays. The average travel distance using the dockless bike-sharing system at weekends is significantly larger than that of workdays. The travel distance distribution could be nicely fitted by the Fréchet distribution of the Generalized Extreme Value (GEV) distribution family. The usage characteristics of shared bikes are correlated with land use and population density around metro stations. No matter in urban or suburban areas, there is a great demand for bike-sharing in densely populated areas with intensive land development, such as university towns in suburban areas. This study improves the understandings regarding the usage patterns of the DLBS system serving as a link between the final destinations (or originations) and metro stations. The results can be helpful to the operation and demand management of DLBS.

ACS Style

Qiang Yan; Kun Gao; Lijun Sun; Minhua Shao. Spatio-Temporal Usage Patterns of Dockless Bike-Sharing Service Linking to a Metro Station: A Case Study in Shanghai, China. Sustainability 2020, 12, 851 .

AMA Style

Qiang Yan, Kun Gao, Lijun Sun, Minhua Shao. Spatio-Temporal Usage Patterns of Dockless Bike-Sharing Service Linking to a Metro Station: A Case Study in Shanghai, China. Sustainability. 2020; 12 (3):851.

Chicago/Turabian Style

Qiang Yan; Kun Gao; Lijun Sun; Minhua Shao. 2020. "Spatio-Temporal Usage Patterns of Dockless Bike-Sharing Service Linking to a Metro Station: A Case Study in Shanghai, China." Sustainability 12, no. 3: 851.

Journal article
Published: 07 October 2019 in Sustainability
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The performance of urban bridges will deteriorate gradually throughout service life. Bridge deterioration prediction is essential for bridge management, especially for maintenance planning and decision-making. By considering the time-dependent reliability in the bridge deterioration process, a Weibull distribution based semi-Markov process model for urban bridge deterioration prediction was proposed in this paper. Historical inspection records stored in the Bridge Manage System (BMS) database in Shanghai since 2004 were investigated. The Weibull distribution was used to characterize the bridge deterioration behavior within each condition rating (CR), and the semi-Markov process was used to calculate the bridge transition probabilities between adjacent CRs. After that, the service life expectancy of urban bridges, the transition probabilities of the deck system and the substructure, and the future CR proportion change caused by deterioration was predicted. The prediction results indicate that the life expectancy of concrete beam bridges is about 77 years. The decay rate of the deck system is the fastest among three major parts, and the substructure has a much longer life expectancy. It suggests that the overall prediction accuracy of the semi-Markov model in network-level is better than the regression analysis method. Furthermore, the proportion of bridges in intact condition will gradually decrease in the next few decades, while the percentage of bridges in the qualified and bad state will increase rapidly. The prediction results show a good agreement with the actual deterioration trend of the urban bridges in Shanghai. In order to alleviate the pressure of bridge maintenance in the future, it is necessary to adopt a more targeted preventive maintenance strategy.

ACS Style

Yu Fang; Lijun Sun. Developing A Semi-Markov Process Model for Bridge Deterioration Prediction in Shanghai. Sustainability 2019, 11, 5524 .

AMA Style

Yu Fang, Lijun Sun. Developing A Semi-Markov Process Model for Bridge Deterioration Prediction in Shanghai. Sustainability. 2019; 11 (19):5524.

Chicago/Turabian Style

Yu Fang; Lijun Sun. 2019. "Developing A Semi-Markov Process Model for Bridge Deterioration Prediction in Shanghai." Sustainability 11, no. 19: 5524.