The Experts below are selected from a list of 48309 Experts worldwide ranked by ideXlab platform
Robert L Lytton - One of the best experts on this subject based on the ideXlab platform.
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enhanced model for thermally induced transverse cracking of Asphalt Pavements
Construction and Building Materials, 2019Co-Authors: Meng Ling, Sheng Hu, Yu Chen, Robert L LyttonAbstract:Abstract Thermal cracking is a non-load associated distress mode of Asphalt Pavements. Finite element models (FEM) were first introduced in this study to determine the thermally induced J-integral at the tip of thermal crack. After extensive runs of the FEM, artificial neural network models were constructed to predict the J-integral, which was used in the Paris’ law to calculate the cumulative thermal crack growth over time and thermal cracking fatigue life. Additionally, Long-term pavement performance data was collected to characterize the thermal cracking in different climatic zones. The calculated fatigue life was well correlated with the observed transverse cracking field performance.
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prediction of field aging gradient in Asphalt Pavements
Transportation Research Record, 2015Co-Authors: Fan Gu, Robert L LyttonAbstract:The aging of Asphalt Pavements is a key factor that influences pavement performance. Aging can be characterized by laboratory tests and prediction models. Common aging prediction models use the change of physical or chemical properties of Asphalt binders based on regression techniques or aging reaction kinetics. The objective of this study was to develop a kinetics-based aging prediction model for the mixture modulus gradient in Asphalt Pavements to study long-term in-service aging. The proposed model was composed of three submodels for baseline modulus, surface modulus, and aging exponent to define the change of the mixture modulus with pavement depth. The model used kinetic parameters (aging activation energy and preexponential factor) of Asphalt mixtures and combined the two reaction rate periods (fast-rate and constant-rate). Laboratory-measured modulus gradients of 29 field cores at different ages were used to determine the model parameters. The laboratory testing condition was converted to the field condition at a given age and corresponding temperature by introducing the rheological activation energy to quantify the temperature dependence of field cores at each age. The end of the fast-rate period or the beginning of the constant-rate period was accurately identified to model these two periods and to determine the associated parameters separately. The results showed that the predictions matched well with the measurements and the calculated model parameters were verified. The proposed aging prediction model took into account the major factors that affect field aging speed of an Asphalt pavement, such as the binder type, aggregate type, air void content, pavement depth, aging temperature, and aging time.
Yanjing Zhao - One of the best experts on this subject based on the ideXlab platform.
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evaluation method for transverse cracking in Asphalt Pavements on freeways
Transportation Research Record, 2010Co-Authors: Lan Zhou, Fujian Ni, Yanjing ZhaoAbstract:Transverse cracking is one of the major distresses in Asphalt Pavements. The objective of this research is to establish an effective evaluation method for transverse cracking in Asphalt Pavements on China's freeways. Two single indicators are presented that assess the key properties of transverse cracking: transverse crack spacing and transverse crack width ratio. The transverse crack condition index (TCCI) is then developed as a comprehensive evaluation index of transverse cracking in this study. The feasibility of this evaluating method was checked with the analysis of field detection data from Wu Xuan freeway in Anhui Province and two other freeways in Jiangsu Province, China. Through the introduction of an expert evaluation, the TCCI was converted to a scale from 0 to 100, and the threshold value was confirmed. Furthermore, the corresponding maintenance treatment method was determined according to the different transverse cracking condition levels. The results showed that the TCCI can make a good asse...
Richard Y Kim - One of the best experts on this subject based on the ideXlab platform.
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mechanistic evaluation of fatigue cracking in Asphalt Pavements
International Journal of Pavement Engineering, 2017Co-Authors: Amirhossein Norouzi, Richard Y KimAbstract:AbstractOver the last several decades, significant research has been conducted to predict the fatigue cracking performance of Asphalt Pavements. Recently, the simplified viscoelastic continuum damage (S-VECD) model was developed as an efficient method of characterising the fatigue performance of Asphalt mixtures under a wide range of loading conditions. Two important material properties that can be determined from the S-VECD model are the damage characteristic curve that defines how damage evolves in a specimen and the energy-based failure criterion that defines when the specimen fails. These two material functions are unique for a given mixture regardless of temperature, mode of loading, stress/strain amplitude and loading history. This study presents the application of the Layered Viscoelastic Crirtical Distresses (LVECD) programme to predict the fatigue performance of 18 pavement sections from different locations in the United States and Canada. The capability of the LVECD programme to capture crack in...
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investigation into top down cracking of Asphalt Pavements in north carolina
Transportation Research Record, 2013Co-Authors: Hong Joon Park, Richard Y KimAbstract:Top-down cracking has become a commonly reported cracking mechanism in Asphalt Pavements worldwide. In top-down cracking, a crack initiates at the surface of an Asphalt concrete pavement and propagates to the bottom of the Asphalt pavement layer. Because the location and governing state of stress for top-down cracking are different from those for bottom-up cracking, analysis of pavement cracking performance must be robust enough to account for the complex mechanisms that are involved in top-down cracking. This study applies the viscoelastic continuum damage finite element model to the evaluation of two pavement sections in North Carolina where top-down cracking has been identified. Small specimen geometries are used to perform simplified viscoelastic continuum damage testing on individual Asphalt layers obtained from field cores. This testing model and the Fourier finite element program are used together for pavement cracking performance simulations, and the joint model uses the structure and layer materi...
Yue Huang - One of the best experts on this subject based on the ideXlab platform.
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design and experiment of thermoelectric Asphalt Pavements with power generation and temperature reduction functions
Energy and Buildings, 2018Co-Authors: Wei Jiang, Jingjing Xiao, Dongdong Yuan, Yue HuangAbstract:Abstract Asphalt Pavements tend to absorb solar energy and accumulate heat, which results in several negative effects. They contribute to the urban heat-island effect, plastic deformation of Pavements, and aging of Asphalt materials. One solution is to convert or transfer the pavement heat. A brand new road thermoelectric generator system (RTEGS) is designed for this purpose. The system added three modules to the traditional Asphalt pavement structure: heat-conduction, thermoelectric-conversion, and cold-end cooling. The modules convert heat absorbed in Asphalt Pavements to electrical energy and reduce the pavement surface temperature. Field testing of the new system subject to a full seasonal change (half a year) was conducted. The data of temperature reduction and voltage output in a field environment were obtained. The results showed that the system reduced the pavement surface temperature by 8–9 °C in hot seasons, and the electrical output from an Asphalt pavement of size 300 mm × 300 mm × 100 mm reached 0.564 V. At this output, a 10,000 m2 (1 km long and 10 m wide) pavement area would generate about 33 kWh of electrical energy in a single day in the summer, not considering the scale effects of the RTEGS. The system provides a new approach to alleviate the urban heat-island effect, and to convert and utilize solar heat absorbed in Asphalt pavement.
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development of a life cycle assessment tool for construction and maintenance of Asphalt Pavements
Journal of Cleaner Production, 2009Co-Authors: Yue Huang, Roger Bird, O HeidrichAbstract:Abstract The increasing use of recycled materials in Asphalt Pavements calls for environmental assessment of such impacts as the energy input and CO 2 footprint. Life cycle assessment (LCA) is being accepted by the road industry for such purpose. It aims to quantify and collate all the environmental impacts from the life time of the product or process. This paper reviews relevant LCA resources worldwide, identifies the knowledge gap for the road industry, and describes the development of an LCA model for pavement construction and maintenance that accommodates recycling and up-to-date research findings. Details are provided of both the methodology and data acquisition. This is followed by a discussion of the challenges of applying LCA to the pavement construction practice, and recommendations for further work. In the case study, the model is applied to an Asphalt paving project at London Heathrow Terminal-5 (LHR), in which natural aggregates were replaced with waste glass, incinerator bottom ash (IBA) and recycled Asphalt Pavements (RAP). Production of hot mix Asphalt and bitumen was found to represent the energy intensive processes. This is followed by data analysis and sensitivity check. Further development of the model includes expanding the database to accommodate the recycling and maintenance practice in the UK, and taking into account the effect that roadwork has on traffic emissions. The LCA model can be further tested and calibrated as a decision support tool for sustainable construction in the road industry.
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a review of the use of recycled solid waste materials in Asphalt Pavements
Resources Conservation and Recycling, 2007Co-Authors: Yue Huang, Roger Bird, O HeidrichAbstract:The construction and maintenance of UK roads consume large amounts of quarried aggregates. The use of secondary (recycled), instead of primary (virgin), materials helps easing landfill pressures and reducing demand of extraction. However, concerns over inferior road performance and additional costs have hindered the widespread use of secondary aggregates in such applications. This is especially the case in surface layers of Asphalt Pavements that may represent a value application for recycled solid waste materials (SWM). Waste glass, steel slag, tyres and plastics are selected for this study, which reviews standards and literature for technical requirements, as well as the performance of Asphalt Pavements constructed using such recycled materials. Waste arising and management indicates that although there is a large potential for supplying secondary materials, a few factors have effectively depressed such recycling activities. Such barriers are described here and may also apply to the secondary use of other SWM. After identifying and quantifying such barriers a brief discussion suggests ways of their removal.
Hong Joon Park - One of the best experts on this subject based on the ideXlab platform.
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Mechanistic evaluation of cracking in in-service Asphalt Pavements
Materials and Structures, 2014Co-Authors: Hong Joon Park, Mehran EslaminiaAbstract:Cracking in Asphalt Pavements is a complex problem that is affected by pavement structural design, material properties, and environmental conditions. It is now well accepted that load-related top-down fatigue cracking (i.e., cracking that initiates at the surface of the pavement and propagates downward) commonly occurs in Asphalt Pavements. Conventional fracture mechanics-based finite element analysis must assume the location of macrocrack initiation a priori and, therefore, is not appropriate for general-purpose cracking simulation. This paper presents the use of the layered viscoelastic pavement analysis for critical distresses (LVECD) program to evaluate 18 Pavements in local condition regions of 9 in-service pavement sites in North Carolina. In order to obtain the material properties of the individual layers from the field-extracted cores, dynamic modulus tests and simplified viscoelastic continuum damage tests are performed using small geometry specimens obtained from 150 mm diameter cores. This study verifies the capability of the LVECD model to capture crack initiation locations, propagation propensity, and cracking severity by comparing the simulation results with the observations of field cores and the field condition survey of in-service Pavements in North Carolina. Overall, the agreement rate between the field core observations and field condition survey and the predicted LVECD simulation results is about 78 % in terms of cracking direction and severity.
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investigation into top down cracking of Asphalt Pavements in north carolina
Transportation Research Record, 2013Co-Authors: Hong Joon Park, Richard Y KimAbstract:Top-down cracking has become a commonly reported cracking mechanism in Asphalt Pavements worldwide. In top-down cracking, a crack initiates at the surface of an Asphalt concrete pavement and propagates to the bottom of the Asphalt pavement layer. Because the location and governing state of stress for top-down cracking are different from those for bottom-up cracking, analysis of pavement cracking performance must be robust enough to account for the complex mechanisms that are involved in top-down cracking. This study applies the viscoelastic continuum damage finite element model to the evaluation of two pavement sections in North Carolina where top-down cracking has been identified. Small specimen geometries are used to perform simplified viscoelastic continuum damage testing on individual Asphalt layers obtained from field cores. This testing model and the Fourier finite element program are used together for pavement cracking performance simulations, and the joint model uses the structure and layer materi...
