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As an environmentally friendly alternative for the production of high-performance modified asphalt by chemical reactions, a liquid-state polyurethane-precursor-based reactive modifier (PRM) was developed and employed in the asphalt modification. In contrast to the traditional solid bitumen modifier, for example, rubber and thermoplastic elastomers, the PRM as a liquid modifier has more significant advantages in reducing energy consumption and improving asphalt performance, which has attracted widespread attention. However, the aging resistance and its mechanism are not clear. In view of this, the aging performance of two PRM-modified bitumen (PRM-70 and PRM-90), under the short-term thermo-oxidative aging, long-term thermo-oxidative aging, and ultraviolet (UV) aging conditions, was investigated through chemical and mechanical methods. The results show that the PRM-90 is more susceptible to the thermos-oxidative aging and UV aging. The use of low-penetration-grade bitumen and ensuring an adequate reaction are beneficial to enhance the aging resistance of PRM-modified bitumen. The impact of aging on high-temperature performance of PRM-modified bitumen is great, followed by the low-temperature performance and the anti-fatigue performance. The mechanic-relevant rheological aging index (RAI) and fracture energy index (FEI) are recommended to evaluate aging properties for PRM-modified bitumen. This study not only provides support for further research on the relationship between the aging properties and mechanical performance of PRM-modified bitumen, but also provides a reference for conducting mechanism analysis.
Liang Zhang; Pengfei Li; Guanfeng Hu; Sufeng Zhang; Bin Hong; HaoPeng Wang; Dawei Wang; Markus Oeser. Study on the Aging Resistance of Polyurethane Precursor Modified Bitumen and its Mechanism. Sustainability 2021, 13, 9520 .
AMA StyleLiang Zhang, Pengfei Li, Guanfeng Hu, Sufeng Zhang, Bin Hong, HaoPeng Wang, Dawei Wang, Markus Oeser. Study on the Aging Resistance of Polyurethane Precursor Modified Bitumen and its Mechanism. Sustainability. 2021; 13 (17):9520.
Chicago/Turabian StyleLiang Zhang; Pengfei Li; Guanfeng Hu; Sufeng Zhang; Bin Hong; HaoPeng Wang; Dawei Wang; Markus Oeser. 2021. "Study on the Aging Resistance of Polyurethane Precursor Modified Bitumen and its Mechanism." Sustainability 13, no. 17: 9520.
At present, the test methods to evaluate the low-temperature performance of asphalt binder focus on bending beam rheometer (BBR), and dynamic shear rheometer (DSR) is mainly used for high-temperature and medium-temperature tests. The reason is that when the test is in the low-temperature range, the instrument compliance errors are an unavoidable problem in DSR test. To solve this, based on the frequency sweep test of DSR, the modified Havriliak-Negami (MHN) model was employed to deduce the temperature at which asphalt binder undergoing the glass transition, and the torsion cylinder (TC) test and differential scanning calorimeter (DSC) were conducted to verify its correctness. Furthermore, the relationship between this approach and the low-temperature performance of asphalt binder is established by nonlinear fitting and linear regression analysis. This study presented an approach to predict the low-temperature performance of asphalt binder based on rheological model, which provides a solution to the difficulty of evaluating the low-temperature performance of asphalt binder using DSR.
Jiaqiu Xu; Zepeng Fan; Jiao Lin; Xuan Yang; Dawei Wang; Markus Oeser. Predicting the low-temperature performance of asphalt binder based on rheological model. Construction and Building Materials 2021, 302, 124401 .
AMA StyleJiaqiu Xu, Zepeng Fan, Jiao Lin, Xuan Yang, Dawei Wang, Markus Oeser. Predicting the low-temperature performance of asphalt binder based on rheological model. Construction and Building Materials. 2021; 302 ():124401.
Chicago/Turabian StyleJiaqiu Xu; Zepeng Fan; Jiao Lin; Xuan Yang; Dawei Wang; Markus Oeser. 2021. "Predicting the low-temperature performance of asphalt binder based on rheological model." Construction and Building Materials 302, no. : 124401.
For road construction, the morphological characteristics of coarse aggregates such as angularity and sphericity have a considerable influence on asphalt pavement performance. In traditional aggregate simulation processes, images of real coarse grains are captured, and their parameters are extracted manually for reproducing them in a numerical simulation such as Discrete Element Modeling (DEM). Generative Adversarial Networks can generate aggregate images, which can be stored in the Aggregate DEM Database directly. In this paper, it has been demonstrated that applying Auxiliary Classifier Wasserstein GANs with gradient penalty (ACWGAN-gp) is reliable and efficient for the establishment of an aggregate image database. In addition, the distribution of original images was compared with that of images generated based on ACGAN and ACWGAN-gp models. Generated images were validated through obtaining identifiable edge coordinates and represented as DEM input in the simulation process. The results prove that the ACWGAN-gp approach can be used for generating aggregate images for the DEM database. It successfully generates high-quality images of aggregates with a representative distribution of morphologies used for DEM simulation. This work shows convenience and efficiency for machine learning applications in the road construction field.
Chonghui Wang; Feifei Li; Quan Liu; Hainian Wang; Pia Benmoussa; Sabina Jeschke; Markus Oeser. Establishment and extension of digital aggregate database using auxiliary classifier Wasserstein GAN with gradient penalty. Construction and Building Materials 2021, 300, 124217 .
AMA StyleChonghui Wang, Feifei Li, Quan Liu, Hainian Wang, Pia Benmoussa, Sabina Jeschke, Markus Oeser. Establishment and extension of digital aggregate database using auxiliary classifier Wasserstein GAN with gradient penalty. Construction and Building Materials. 2021; 300 ():124217.
Chicago/Turabian StyleChonghui Wang; Feifei Li; Quan Liu; Hainian Wang; Pia Benmoussa; Sabina Jeschke; Markus Oeser. 2021. "Establishment and extension of digital aggregate database using auxiliary classifier Wasserstein GAN with gradient penalty." Construction and Building Materials 300, no. : 124217.
Tire—pavement interaction behaviours result in large amounts of wearing waste matter, which attaches to the surface of the pavement and is directly exposed to the surrounding environment. This kind of matter imposes a great challenge to the environment of the road area. The current study is devoted to carrying out a comprehensive investigation of the formation mechanism of tire—pavement wearing waste (TPWW), as well as the resulting environmental risks. A self-developed piece of accelerated polishing equipment, the Harbin advanced polishing machine (HAPM), was employed to simulate the wearing process between vehicle tires and pavement surfaces, and the TPWW was collected to conduct morphological, physical, and chemical characterisations. The results from this study show that the production rate of TPWW decreases with the increase in polishing duration, and the coarse particles (diameters greater than 0.425 mm) account for most of the TPWW obtained. The fine fraction (diameter smaller than 0.425 mm) of the TPWW comprises variously sized and irregularly shaped rubber particles from the tire, as well as uniformly sized and angular fine aggregates. The environmental analysis results show that volatile alkanes (C9–C16) are the major organic contaminants in TPWW. The Open-Graded Friction Course (OGFC) asphalt mixture containing crumb rubber as a modifier showed the highest risk of heavy metal pollution, and special concern must be given to tire materials for the purpose of improving the environmental conditions of road areas. The use of polyurethane as a binder material in the production of pavement mixtures has an environmental benefit in terms of pollution from both organic contaminants and heavy metals.
Kechen Wang; Xiangyu Chu; Jiao Lin; Qilin Yang; Zepeng Fan; Dawei Wang; Markus Oeser. Investigation of the Formation Mechanism and Environmental Risk of Tire—Pavement Wearing Waste (TPWW). Sustainability 2021, 13, 8172 .
AMA StyleKechen Wang, Xiangyu Chu, Jiao Lin, Qilin Yang, Zepeng Fan, Dawei Wang, Markus Oeser. Investigation of the Formation Mechanism and Environmental Risk of Tire—Pavement Wearing Waste (TPWW). Sustainability. 2021; 13 (15):8172.
Chicago/Turabian StyleKechen Wang; Xiangyu Chu; Jiao Lin; Qilin Yang; Zepeng Fan; Dawei Wang; Markus Oeser. 2021. "Investigation of the Formation Mechanism and Environmental Risk of Tire—Pavement Wearing Waste (TPWW)." Sustainability 13, no. 15: 8172.
To investigate the damage behavior of asphalt pavements under the combination of temperature fields and traffic loadings, a two-dimensional (2D) mesostructure-based finite-element method was developed. Temperature fields in an asphalt pavement at midday and midnight of summer and winter seasons were considered according to real air temperature data of an inland city in China. The mesostructure of the asphalt concrete layer was established based on digital image processing (DIP) technology from the cross-section image of an asphalt mixture specimen. A multiscale simulation approach was employed to link the mechanical behaviors of the asphalt concrete layer at different length scales. During the simulation, the traffic and temperature loadings were applied to the macroscale pavement model; subsequently, the strain responses and temperature distributions were extracted from critical positions of the pavement and transferred to the mesoscale model. In addition, the thermal expansion/contraction behavior of the asphalt mixture was taken into account. In this way, the stress distributions and damage behavior of the asphalt pavement induced by both the traffic tire loadings and temperature variations were well simulated while considering the heterogeneous features of the asphalt mixture. The results showed that the thermal expansion/contraction induced by the temperature changes had a significant influence on the maximum principal stress distributions within the asphalt layer, which further can influence the damage behavior of the asphalt pavements. In particular, significant thermal stress caused by the temperature variation appeared on the top of the asphalt concrete (AC) layer in the winter, and the thermal expansion/contraction can affect remarkably the pavement responses at midnight in the winter.
Cong Du; Yiren Sun; Jingyun Chen; Changjun Zhou; Pengfei Liu; Dawei Wang; Markus Oeser. Coupled Thermomechanical Damage Behavior Analysis of Asphalt Pavements Using a 2D Mesostructure-Based Finite-Element Method. Journal of Transportation Engineering, Part B: Pavements 2021, 147, 04021012 .
AMA StyleCong Du, Yiren Sun, Jingyun Chen, Changjun Zhou, Pengfei Liu, Dawei Wang, Markus Oeser. Coupled Thermomechanical Damage Behavior Analysis of Asphalt Pavements Using a 2D Mesostructure-Based Finite-Element Method. Journal of Transportation Engineering, Part B: Pavements. 2021; 147 (2):04021012.
Chicago/Turabian StyleCong Du; Yiren Sun; Jingyun Chen; Changjun Zhou; Pengfei Liu; Dawei Wang; Markus Oeser. 2021. "Coupled Thermomechanical Damage Behavior Analysis of Asphalt Pavements Using a 2D Mesostructure-Based Finite-Element Method." Journal of Transportation Engineering, Part B: Pavements 147, no. 2: 04021012.
Reversible aging refers to a time-dependent stiffening of asphalt binder that results from the time-delayed increase in stiffness when the asphalt binder is stored at low temperatures. The increase in stiffness will distinctly affect the low temperature performance of the asphalt binder, but existing researches rarely consider this. This paper aims to investigate the effects of reversible aging on the low temperature performance of asphalt binders, and to reveal the underlying mechanism of reversible aging. To this end, four different types of asphalt binders were selected for the extended bending beam rheometer (EBBR) test at different conditioning times. The thermal stress was computed based on the rheological data obtained from the EBBR test to quantify the influence of low temperature reversible aging on the cracking resistance of the asphalt binders. The Avrami isothermal crystallization kinetics theory was used to analyse the reversible aging process of asphalt binders from the perspective of macro-crystal structure. Furthermore, the molecular dynamics was performed to simulate the reversible aging process of asphalt binders from a microscopic point of view. The results from this study show that the low temperature performance of asphalt binders continues to decline with the extension of the conditioning time, which is manifested by the increase in grade loss, thermal stress and critical cracking temperature. Reversible aging exhibits great impact on the low temperature performance of asphalt binders by lowering the low temperature grade of asphalt binders up to one grade. The Avrami isothermal crystallization kinetic theory can accurately characterize the reversible aging tendency of asphalt binders. The molecular dynamics simulation results show that the asphaltene component contributes the most to the reversible aging of asphalt binder.
Jiaqiu Xu; Zepeng Fan; Jiao Lin; Pengfei Liu; Dawei Wang; Markus Oeser. Study on the effects of reversible aging on the low temperature performance of asphalt binders. Construction and Building Materials 2021, 295, 123604 .
AMA StyleJiaqiu Xu, Zepeng Fan, Jiao Lin, Pengfei Liu, Dawei Wang, Markus Oeser. Study on the effects of reversible aging on the low temperature performance of asphalt binders. Construction and Building Materials. 2021; 295 ():123604.
Chicago/Turabian StyleJiaqiu Xu; Zepeng Fan; Jiao Lin; Pengfei Liu; Dawei Wang; Markus Oeser. 2021. "Study on the effects of reversible aging on the low temperature performance of asphalt binders." Construction and Building Materials 295, no. : 123604.
Pavement pre-compaction is vital for asphalt pavement construction due to its influence on the quality and service life of asphalt pavement. Conventional methods of evaluating and researching the pavement pre-compaction are based on mixture density with empirical theories, which cannot provide an understanding of asphalt-screed interaction during pre-compaction. An innovative approach is developed in this paper to evaluate pavement pre-compaction through Discrete Element Model (DEM) simulation. The contact model and input parameters were discussed and defined separately based on the real condition of paving compaction. A field test about paving compaction was conducted as well for the model validation, in the test track, the operations of paving machine can be adjusted such as paving speed, paving angle, and paving thickness. In addition, the optimized working operation was recommended in this paper based on the results from DEM simulation as well as filed test. Finally, a method to evaluate the pre-compaction of bulk materials via the average aggregate angular velocity was proposed in this study and validated through the test track, and the index Compaction Increase Ratio (CIR) was defined to compare and describe the quality of pre-compaction.
Chonghui Wang; Milad Moharekpour; Quan Liu; Zeyu Zhang; Pengfei Liu; Markus Oeser. Investigation on asphalt-screed interaction during pre-compaction: Improving paving effect via numerical simulation. Construction and Building Materials 2021, 289, 123164 .
AMA StyleChonghui Wang, Milad Moharekpour, Quan Liu, Zeyu Zhang, Pengfei Liu, Markus Oeser. Investigation on asphalt-screed interaction during pre-compaction: Improving paving effect via numerical simulation. Construction and Building Materials. 2021; 289 ():123164.
Chicago/Turabian StyleChonghui Wang; Milad Moharekpour; Quan Liu; Zeyu Zhang; Pengfei Liu; Markus Oeser. 2021. "Investigation on asphalt-screed interaction during pre-compaction: Improving paving effect via numerical simulation." Construction and Building Materials 289, no. : 123164.
Cold-mixed epoxy bitumen (CEB) has been presented as an eco-friendly paving material used for steel bridge deck pavements. This study performed an investigation on three preparation methods of CEBs, which includes one kind of three-component and two kinds of two-component methods. The curing process was characterized through the viscosity measurement. Meanwhile, the microstructure of CEBs was observed using fluorescence microscopy. Mechanical properties of CEBs prepared with different methods were characterized by employing direct tensile tests and dynamic mechanical analysis (DMA). Finally, thermogravimetric analysis (TGA/DTG) was conducted to feature the thermal stability of CEBs. The results indicated that the preparation methods significantly affected the performance of cured CEBs, although the same mix design was adopted. The curing temperature determined the curing rate of CEBs, while the preparation methods dominated the morphological characteristic of cured CEBs. The three-component preparation method can achieve acceptable mechanical performance for engineering requirements. As for two-component methods, the curing agent is supposed to be mixed with bitumen to obtain satisfying microstructures of CEBs.
Quan Liu; Chonghui Wang; Zeyu Zhang; Cong Du; Pengfei Liu; Markus Oeser. Influence of preparation methods on the performance of cold-mixed epoxy bitumen. Materials and Structures 2021, 54, 1 -13.
AMA StyleQuan Liu, Chonghui Wang, Zeyu Zhang, Cong Du, Pengfei Liu, Markus Oeser. Influence of preparation methods on the performance of cold-mixed epoxy bitumen. Materials and Structures. 2021; 54 (2):1-13.
Chicago/Turabian StyleQuan Liu; Chonghui Wang; Zeyu Zhang; Cong Du; Pengfei Liu; Markus Oeser. 2021. "Influence of preparation methods on the performance of cold-mixed epoxy bitumen." Materials and Structures 54, no. 2: 1-13.
One of the key steps in pavement maintenance is the fast and accurate identification of the distresses, defects, and pavement markings and ability to conduct the maintenance before the irreversible damages. Recently, convolution neural network (CNN) has emerged as a powerful tool to automatically identify the pavement cracks, where many of the CNN models take long computation time. To solve the problem, an adaptive lightweight model, named MobileCrack, is proposed in this study. MobileCrack realizes the fast computation using the following settings: (1) reduce input image size, where besides the original input images, images with a side length of 1/2,1/4,1/8… of that of the original square images are also input into the model by using the resize command; (2) group convolution is used; and (3) global average pooling is used because it normally has less parameters compared with the fully connected layer. MobileCrack will then compute the combinations of different resized input images and different neural network structures, to find the optimal reduced image size and neural network structure with satisfactory accuracy using reasonable computation time. To verify the applicability of MobileCrack, 10,000 input images with size 400×400 are trained for the classification task of crack, sealed crack, pavement marking, and pavement matrix. Based on the computation results of combinations of images with different sizes (400×400, 200×200, 100×100, and 50×50) and different stacking numbers of core modules n (3, 4, 5, and 6), the optimal model is determined as image size 200×200 and n=4, where the test accuracy is 0.865 within reasonable computation time (runtime=47 ms to test one image). This optimal model will be automatically used for further tests with image size 400×400 for a fast computation, which realizes the lightweight adaptive goal. Results also show that the test accuracy of MobileCrack is higher than that of the AlexNet and visual geometry group (VGG), and the parameters of MobileCrack are approximately 1/4 of that of the classic lightweight CNN model MobileNet, which saves the storage space. It is concluded that that the proposed adaptive lightweight CNN model, MobileCrack, can be used for the fast object classification on asphalt pavement crack images.
Yue Hou; Qiuhan Li; Qiang Han; Bo Peng; Linbing Wang; Xingyu Gu; Dawei Wang. MobileCrack: Object Classification in Asphalt Pavements Using an Adaptive Lightweight Deep Learning. Journal of Transportation Engineering, Part B: Pavements 2021, 147, 04020092 .
AMA StyleYue Hou, Qiuhan Li, Qiang Han, Bo Peng, Linbing Wang, Xingyu Gu, Dawei Wang. MobileCrack: Object Classification in Asphalt Pavements Using an Adaptive Lightweight Deep Learning. Journal of Transportation Engineering, Part B: Pavements. 2021; 147 (1):04020092.
Chicago/Turabian StyleYue Hou; Qiuhan Li; Qiang Han; Bo Peng; Linbing Wang; Xingyu Gu; Dawei Wang. 2021. "MobileCrack: Object Classification in Asphalt Pavements Using an Adaptive Lightweight Deep Learning." Journal of Transportation Engineering, Part B: Pavements 147, no. 1: 04020092.
The interfacial behavior between bitumen and aggregate is not well understood so far since it is sensitive to various factors including chemistry of the components, morphology of the interface, and the environmental and loading conditions. Moreover, the mechanisms of action for different factors occur at distinct time and length scales. The multi-factor and multi-scale natures bring great challenge to the interfacial behavior between bitumen and aggregate. This study aims to exploit a deep understanding of the interfacial behavior from the perspective of aggregate mineralogy at the molecular scale and relate this fundamental understanding to affinity between bitumen and aggregate. For this, the affinity between bitumen and six kinds of aggregates were evaluated by the rolling bottle test, and adhesion mechanisms between bitumen and component minerals were investigated through molecular dynamics simulations. The rolling bottle test results show that the diabase has the best moisture damage resistance, followed by the greywacke I, basalt and greywacke II. The two granite aggregates show the worst moisture damage resistance. The molecular dynamics simulation indicates the existence of competitive adsorption between bitumen and water molecules at the mineral surface, and the penetration capacity of bitumen molecule is greatly affected by the mineral property. Aggregates with higher content of nepheline, chlorite, pyroxene and olivine minerals are more likely exhibit better moisture damage resistance while aggregates with higher content of quartz, plagioclase and calcite minerals do the opposite. The findings from this research provide insights into the underlying mechanism of aggregate mineralogy influence on affinity between bitumen and aggregate.
Zepeng Fan; Jiao Lin; Zixuan Chen; Pengfei Liu; Dawei Wang; Markus Oeser. Multiscale understanding of interfacial behavior between bitumen and aggregate: From the aggregate mineralogical genome aspect. Construction and Building Materials 2020, 271, 121607 .
AMA StyleZepeng Fan, Jiao Lin, Zixuan Chen, Pengfei Liu, Dawei Wang, Markus Oeser. Multiscale understanding of interfacial behavior between bitumen and aggregate: From the aggregate mineralogical genome aspect. Construction and Building Materials. 2020; 271 ():121607.
Chicago/Turabian StyleZepeng Fan; Jiao Lin; Zixuan Chen; Pengfei Liu; Dawei Wang; Markus Oeser. 2020. "Multiscale understanding of interfacial behavior between bitumen and aggregate: From the aggregate mineralogical genome aspect." Construction and Building Materials 271, no. : 121607.
During the construction process of tunnel asphalt pavement, a lot of asphalt fume can be generated. The asphalt fume usually cannot dissipate quickly during the tunnel’s construction, resulting in significant harm to the workers’ health and extending traffic congestion. To solve the problem, a new tunnel pavement, polyurethane (PU) ultra-thin friction courses (PU/UTFC) was proposed, with excellent mechanical properties and wear resistance, and almost no harmful emissions due to its room temperature construction. For this purpose, two PU mixtures (PUM), PU-based open-graded friction courses (PU/OGFC) and PU concrete (PUC), with three different component ratios were investigated in terms of the mechanical properties, functional properties, environmental impact evaluation, and thermo-mechanical properties. Results have shown that PUM, compared to conventional asphalt mixtures, possesses excellent mechanical properties, functional properties, such as skid resistance, noise absorption performance and flame-retardant property, as well as sound environmental properties. Specifically, the increase in isocyanate index (R) can significantly enhance the mechanical properties and water resistance of PUM but will reduce its freeze-thawing resistance. In contrast to PU/OGFC, PUC has higher mechanical properties but lower water stability. The above two PU/UTFCs will resolve significant problems in asphalt pavement in the tunnel and possess a broader application prospect.
Bin Hong; Guoyang Lu; Junling Gao; Shuai Dong; Dawei Wang. Green tunnel pavement: Polyurethane ultra-thin friction course and its performance characterization. Journal of Cleaner Production 2020, 289, 125131 .
AMA StyleBin Hong, Guoyang Lu, Junling Gao, Shuai Dong, Dawei Wang. Green tunnel pavement: Polyurethane ultra-thin friction course and its performance characterization. Journal of Cleaner Production. 2020; 289 ():125131.
Chicago/Turabian StyleBin Hong; Guoyang Lu; Junling Gao; Shuai Dong; Dawei Wang. 2020. "Green tunnel pavement: Polyurethane ultra-thin friction course and its performance characterization." Journal of Cleaner Production 289, no. : 125131.
In recent years, the polyurethane (PU) was widely investigated and applied in pavement engineering as a sustainable binder to develop pavment materials with superior mechanical and functional properties. However, the two-component PU binders exhibit rapid curing and thus it is difficult to control the material workability through paving and compaction. Hence, the precast mehtod concept has been proposed to obtain good workability as well as the optimal engineering performances of the polyurethane mixtures (PUMs) used in pavement. In the current study, a method based on the vacuum assisted resin transfer molding (VARTM) technology was developed for the precast PUMs. The results showed that the optimal VARTM-based preparation method is to perfusion the normally compacted specimens with 2 ~ 4 wt% PU content to obtain the optimal compaction uniformity and mechanical properties. Based on the developed methods, the water and freeze-thaw sensitivity of the VARTM-formed PUM samples were evaluated by performing laboratory tests. According to the immersion Marshall stability and freeze-thaw splitting tests, the VARTM-formed PUM samples showed improved Marshall and water stability comparing the performance of samples developed using a conventional compaction method. Given the above excellent performances, the VARTM-formed PUMs were validated to serve as the rapid repair pavement materials or pavement materials with high waterproof performance requirements, for example, the bridge deck paving materials. This research has made a breakthrough in the construction technology of PUMs to a large extent. It has made significant contributions to the further application and promotion of PU binder in transportation infrastructures.
Bin Hong; Guoyang Lu; Junling Gao; Dawei Wang. Evaluation of polyurethane dense graded concrete prepared using the vacuum assisted resin transfer molding technology. Construction and Building Materials 2020, 269, 121340 .
AMA StyleBin Hong, Guoyang Lu, Junling Gao, Dawei Wang. Evaluation of polyurethane dense graded concrete prepared using the vacuum assisted resin transfer molding technology. Construction and Building Materials. 2020; 269 ():121340.
Chicago/Turabian StyleBin Hong; Guoyang Lu; Junling Gao; Dawei Wang. 2020. "Evaluation of polyurethane dense graded concrete prepared using the vacuum assisted resin transfer molding technology." Construction and Building Materials 269, no. : 121340.
Using alternative extender as a substitute for bitumen is one of the most effective approaches to construct asphalt pavements. In this study, the feasibility of using lignin as an extender for bitumen was investigated. According to the literature review and preliminary tests, the ratio of bitumen to lignin was fixed at 4:1 by mass. The viscosity measurement determined the workability of lignin modified bitumen (LMB). Rheological properties in a broader temperature range were investigated through the dynamic shear rheometer (DSR) and bending beam rheometer (BBR). The anti-aging performance of LMB was estimated by employing the thin-film oven test (TFOT) and Fourier Transform Infrared Spectroscopy (FTIR). Besides, the storage stability of LMB was discussed in terms of morphology, lignin concentration, and mechanical properties. Lastly, the thermal stability of LMB was examined to eliminate the safety concern in construction. The results indicated that lignin showed explicit chemical activities (associated hydroxyl -OH and carbonyl groups -C=O), which significantly affected the bitumen properties from varying perspectives. The stiffness of bitumen increased, and the temperature susceptibility of bitumen was reduced after the incorporation of lignin. Meanwhile, the mixing and paving temperatures for the pavement construction increased by over 10°C. The presence of abundant associated hydroxyl in lignin was the primary factor that changes the anti-aging capacity of bitumen. The problem of lignin segregation was reasonably serious but was solved by adding additives. In general, the lignin could be a decent extender for bitumen with the appropriate procedure in practice.
Jiantao Wu; Quan Liu; Chonghui Wang; Wenjuan Wu; Weipeng Han. Investigation of lignin as an alternative extender of bitumen for asphalt pavements. Journal of Cleaner Production 2020, 283, 124663 .
AMA StyleJiantao Wu, Quan Liu, Chonghui Wang, Wenjuan Wu, Weipeng Han. Investigation of lignin as an alternative extender of bitumen for asphalt pavements. Journal of Cleaner Production. 2020; 283 ():124663.
Chicago/Turabian StyleJiantao Wu; Quan Liu; Chonghui Wang; Wenjuan Wu; Weipeng Han. 2020. "Investigation of lignin as an alternative extender of bitumen for asphalt pavements." Journal of Cleaner Production 283, no. : 124663.
Functional carbon nanomaterials are incorporated in bitumen composites to enhance their mechanical performance; however, this process is significantly hindered by the poor dispersion of the nanomaterials in the bitumen composite bulk, and their sluggish interfacial interaction with the bitumen matrix. In this study, graphene/carbon nanotube (CNT) hybrid materials were used to reinforce a bitumen composite, exhibiting improved dispersion, while advancing the interfacial interactions between the carbon nanomaterials and the bitumen matrix. Comparing with the control bitumen sample, a Bitumen/Graphene composite and a Bitumen/CNT composite, the graphene/CNT hybrid notably improved several properties of the bitumen structure, such as rutting resistance, creep and recovery behavior, permanent deformation resistance, low-temperature cracking resistance and the degree of crosslinking in the bitumen. In particular, bitumen binders with 0.2 wt.% graphene and 0.8 wt.% CNT composite presented the optimal mechanical performance. These improvements can be attributed to the synergetic effects of the material and the formation of 1D-2D hybrid structures, which apart from increasing the contact area, effectively enhanced stress transfer at graphene/CNT and bitumen interface.
Qilin Yang; Yue Qian; Zepeng Fan; Jiao Lin; Dawei Wang; Jing Zhong; Markus Oeser. Exploiting the synergetic effects of graphene and carbon nanotubes on the mechanical properties of bitumen composites. Carbon 2020, 172, 402 -413.
AMA StyleQilin Yang, Yue Qian, Zepeng Fan, Jiao Lin, Dawei Wang, Jing Zhong, Markus Oeser. Exploiting the synergetic effects of graphene and carbon nanotubes on the mechanical properties of bitumen composites. Carbon. 2020; 172 ():402-413.
Chicago/Turabian StyleQilin Yang; Yue Qian; Zepeng Fan; Jiao Lin; Dawei Wang; Jing Zhong; Markus Oeser. 2020. "Exploiting the synergetic effects of graphene and carbon nanotubes on the mechanical properties of bitumen composites." Carbon 172, no. : 402-413.
In order to further understand the shape memory mechanism of a silicon dioxide/shape memory polyurethane (SiO2/SMPU) composite, the thermodynamic properties and shape memory behaviors of prepared SiO2/SMPU were characterized. Dynamic changes in the molecular orientation and interphase structures of SiO2/SMPU during a shape memory cycle were then discussed according to the small angle X-ray scattering theory, Guinier’s law, Porod approximation, and fractal dimension theorem. In this paper, a dynamic mechanical analyzer (DMA) helped to determine the glass transition start temperature (Tg) by taking the onset point of the sigmoidal change in the storage modulus, while transition temperature (Ttrans) was defined by the peak of tan δ, then the test and the calculated results indicated that the Tg of SiO2/SMPU was 50.4 °C, and the Ttrans of SiO2/SMPU was 72.18 °C. SiO2/SMPU showed good shape memory performance. The programmed SiO2/SMPU showed quite obvious microphase separation and molecular orientation. Large-size sheets and long-period structures were formed in the programmed SiO2/SMPU, which increases the electron density difference. Furthermore, some hard segments had been rearranged, and their gyration radii decreased. In addition, several defects formed at the interfaces of SiO2/SMPU, which caused the generation of space charges, thus leading to local electron density fluctuations. The blurred interphase structure and the intermediate layer formed in the programmed SiO2/SMPU and there was evident crystal damage and chemical bond breakage in the recovered SiO2/SMPU. Finally, the original and recovered SiO2/SMPU samples belong to the surface fractal system, but the programmed sample belongs to the mass fractal and reforms two-phase structures. This study provides an insight into the shape memory mechanism of the SiO2/SMPU composite.
Shuang Shi; Tao Xu; Dawei Wang; Markus Oeser. The Difference in Molecular Orientation and Interphase Structure of SiO2/Shape Memory Polyurethane in Original, Programmed and Recovered States during Shape Memory Process. Polymers 2020, 12, 1994 .
AMA StyleShuang Shi, Tao Xu, Dawei Wang, Markus Oeser. The Difference in Molecular Orientation and Interphase Structure of SiO2/Shape Memory Polyurethane in Original, Programmed and Recovered States during Shape Memory Process. Polymers. 2020; 12 (9):1994.
Chicago/Turabian StyleShuang Shi; Tao Xu; Dawei Wang; Markus Oeser. 2020. "The Difference in Molecular Orientation and Interphase Structure of SiO2/Shape Memory Polyurethane in Original, Programmed and Recovered States during Shape Memory Process." Polymers 12, no. 9: 1994.
The dynamic Shear Rheometer (DSR) test is a standard method used to characterize the rheological properties of bitumen binders. Prior research substantiates the belief that, given that measured results are dependent on the rheometer gap size, currently recommended rheometer gap sizes (1 mm/2mm) cannot represent the mechanical properties of bitumen in asphalt mixtures. This study focused on the effect of gap size on the rheological property of bitumen binders. To this end, three bitumen binders were measured at different rheometer gap sizes (10 ~ 1000 μm). Subsequently, the rheological properties, including the complex modulus, phase angle, master curve, black diagram, were discussed. The results indicated that the measured rheological properties of bitumen binders are related to the testing gap size. In particular, as the gap size decreases, the complex modulus tends to decrease. Due to the presence of modifiers, the effect of the rheometer gap size also depends on the type of bitumen. The selective adsorption and colloidal theories were introduced to understand the effect of gap size. Additionally, a mathematical relationship called Temperature-Gap Superposition Principle (TGSP) was proposed to establish the relationship between the measured complex moduli in the standard state and the thin state.
Quan Liu; Jiantao Wu; Xin Qu; Chonghui Wang; Markus Oeser. Investigation of bitumen rheological properties measured at different rheometer gap sizes. Construction and Building Materials 2020, 265, 120287 .
AMA StyleQuan Liu, Jiantao Wu, Xin Qu, Chonghui Wang, Markus Oeser. Investigation of bitumen rheological properties measured at different rheometer gap sizes. Construction and Building Materials. 2020; 265 ():120287.
Chicago/Turabian StyleQuan Liu; Jiantao Wu; Xin Qu; Chonghui Wang; Markus Oeser. 2020. "Investigation of bitumen rheological properties measured at different rheometer gap sizes." Construction and Building Materials 265, no. : 120287.
Dawei Wang; Markus Oeser. Outstanding journal leading the future development of civil and infrastructure engineering. Computer-Aided Civil and Infrastructure Engineering 2020, 1 .
AMA StyleDawei Wang, Markus Oeser. Outstanding journal leading the future development of civil and infrastructure engineering. Computer-Aided Civil and Infrastructure Engineering. 2020; ():1.
Chicago/Turabian StyleDawei Wang; Markus Oeser. 2020. "Outstanding journal leading the future development of civil and infrastructure engineering." Computer-Aided Civil and Infrastructure Engineering , no. : 1.
Emulsified asphalt (EA) is an environment-friendly paving material that is commonly used as the binder of the interlay stress-absorbing composite (ISAC) layer. Roughening the surface of glass fiber by chemical treating is an effective approach to improve the adhesion between glass fiber and EA. However, the effects of the fiber treatment method on the performance of fiber-reinforced EA (FEA) still remain unclear. In this study, glass fiber, which is commonly used in the ISAC layer, was firstly treated with six methods (three etchants in two concentrations). Fibers were then incorporated into EA to prepare FEA samples. Finally, laboratory tests, including Scanning electron microscope (SEM) test, Fourier-transform infrared spectroscopy (FTIR) test, contact angle test, surface tension test, dynamic shear rheometer (DSR) test, and direct tensile test, were performed to evaluate the changes in the physical and chemical properties of glass fiber, EA, and FEA. The experimental results indicated that etching roughened the surface of glass fiber, increased the adhesion work of EA-glass fiber and the fracture strength of FEA. In addition, it was found that the interaction between glass fiber and EA was physical bonding and the performance of FEAs depended on the glass fiber treatment method. Sulfuric acid with a concentration of 2 mol/L was recommended as the optimal glass fiber etchant.
Yanyan Liu; Zeyu Zhang; Lijuan Tan; Yong Xu; Chonghui Wang; Pengfei Liu; Huayang Yu; Markus Oeser. Laboratory evaluation of emulsified asphalt reinforced with glass fiber treated with different methods. Journal of Cleaner Production 2020, 274, 123116 .
AMA StyleYanyan Liu, Zeyu Zhang, Lijuan Tan, Yong Xu, Chonghui Wang, Pengfei Liu, Huayang Yu, Markus Oeser. Laboratory evaluation of emulsified asphalt reinforced with glass fiber treated with different methods. Journal of Cleaner Production. 2020; 274 ():123116.
Chicago/Turabian StyleYanyan Liu; Zeyu Zhang; Lijuan Tan; Yong Xu; Chonghui Wang; Pengfei Liu; Huayang Yu; Markus Oeser. 2020. "Laboratory evaluation of emulsified asphalt reinforced with glass fiber treated with different methods." Journal of Cleaner Production 274, no. : 123116.
Recycling of construction and demolition (C&D) waste is one of the most effective ways to develop sustainable pavements. In this study, the feasibility of using ceramic waste as an alternative source for fine aggregate to improve the polishing resistance of cement mortar is investigated. The recycled fine aggregates used in this study originate from sanitary ceramic waste; the physical and chemical properties of the Recycled Ceramic Aggregates (RCA) were determined. The optimal RCA content in the mortar was determined based on the mechanical strength of the resulting composite. The polishing resistance of coarse and fine RCA was characterized with the Polished Stone Value (PSV) test and the Wehner/Schulze (W/S) test, respectively. The test results indicate that the polishing resistance of RCA is significantly better than that of commonly used mineral aggregate. Lastly, the self-developed Aachen Polishing Machine (APM) was applied to validate the improvement of RCA on the polishing resistance of cement mortar under realistic loading conditions. The cement mortar containing RCA exhibits a better long-term polishing resistance than the traditional mortar. The results from this study provide insights into the application of RCA in concrete pavements and the improvement of material properties.
Guoyang Lu; Zepeng Fan; Zengqing Sun; Pengfei Liu; Zhen Leng; Dawei Wang; Markus Oeser. Improving the polishing resistance of cement mortar by using recycled ceramic. Resources, Conservation and Recycling 2020, 158, 104796 .
AMA StyleGuoyang Lu, Zepeng Fan, Zengqing Sun, Pengfei Liu, Zhen Leng, Dawei Wang, Markus Oeser. Improving the polishing resistance of cement mortar by using recycled ceramic. Resources, Conservation and Recycling. 2020; 158 ():104796.
Chicago/Turabian StyleGuoyang Lu; Zepeng Fan; Zengqing Sun; Pengfei Liu; Zhen Leng; Dawei Wang; Markus Oeser. 2020. "Improving the polishing resistance of cement mortar by using recycled ceramic." Resources, Conservation and Recycling 158, no. : 104796.
In the current approaches to structural analysis for asphalt pavements, the entire pavement material is usually treated to identical material, which disregards the distinct heterogeneity of asphalt mixture. Asphalt mixture is actually a multi-phase heterogeneous material that is composed of air voids, aggregate and asphalt binder. In this study, asphalt specimens were drilled from a test track and the indirect tensile fatigue test was conducted to study the fatigue properties. Digital Image Processing (DIP) was used to investigate the microstructural changes of the asphalt specimens based on X-ray Computed Tomography (X-ray CT) images. The aggregate orientation and number of aggregate contact points were determined. The distribution of the air-voids content and shape index of air voids before and after the fatigue tests were comprehensively discussed. According to the results, the microscopic analysis can effectively predict the evolutions of the internal structures of asphalt mixtures during fatigue damage. The heterogeneity due to different degrees of compaction significantly affects the fatigue properties of the asphalt mixtures. This study not only provides support for the further research on the relationship between the microstructural characteristics and mechanical damages of asphalt mixture but also provides implications for conducting the structural mechanical analysis of asphalt pavement.
Tianshuai Li; Pengfei Liu; Cong Du; Marc Schnittcher; Jing Hu; Dawei Wang; Markus Oeser. Microstructural analysis of the effects of compaction on fatigue properties of asphalt mixtures. International Journal of Pavement Engineering 2020, 1 -12.
AMA StyleTianshuai Li, Pengfei Liu, Cong Du, Marc Schnittcher, Jing Hu, Dawei Wang, Markus Oeser. Microstructural analysis of the effects of compaction on fatigue properties of asphalt mixtures. International Journal of Pavement Engineering. 2020; ():1-12.
Chicago/Turabian StyleTianshuai Li; Pengfei Liu; Cong Du; Marc Schnittcher; Jing Hu; Dawei Wang; Markus Oeser. 2020. "Microstructural analysis of the effects of compaction on fatigue properties of asphalt mixtures." International Journal of Pavement Engineering , no. : 1-12.