scholarly journals Recommendation of Suitable Loading Waveforms and Wavelength Equations for Dynamic Modulus Based on Measured Wheel Loads

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Xiongwei Dai ◽  
Xiaodi Hu ◽  
Ying Gao
Keyword(s):  
Compressive Stress ◽  
Dynamic Modulus ◽  
Least Squares Method ◽  
Structure Design ◽  
Vertical Stress ◽  
Finite Element Program ◽  
Stress Pulse ◽  
Different Depths ◽  
Pavement Structure ◽  
Pavement Structures

Dynamic modulus is a key parameter in the pavement structure design and analysis. A haversine loading waveform is the most widely recommended waveform in the laboratory to obtain the dynamic modulus of asphalt mixtures by test protocols, which may not completely represent all field loading conditions. The aim of this study is to investigate the suitable vertical compressive stress pulse waveforms at different depths under different pavement structures and to obtain the best fitting waveforms by using the least squares method. Specifically, the vertical compressive stress of different pavement structures was calculated by utilizing a three-dimensional finite element program incorporating with the measured wheel loads. The results revealed that the vertical stress pulse waveforms at different depths in asphalt layer were different within different pavement structure combinations. Generally, the square waveform fitted the vertical stress pulse waveform better for the shallow depth of the surface layer. The haversine waveform became more suitable while the depth increased. The bell waveform was better when the depth went deeper (i.e., 10 cm). In addition, the method of choosing waveforms at different depths of different pavement structures was provided, and the equation of calculating wavelength was recommended. Moreover, dynamic modulus under different loading waveforms were analysed through laboratory test, and the process for obtaining dynamic modulus of asphalt layer in any depth was presented.

Sponge roads: the permeable asphalt pavement structures based on rainfall characteristics in central plains urban agglomeration of China

2019 ◽  
Vol 80 (9) ◽  
pp. 1740-1750 ◽  
Author(s):  
Xiaodong Guo ◽  
Jiupeng Zhang ◽  
Bochao Zhou ◽  
Wolong Liu ◽  
Jianzhong Pei ◽  
...  
Keyword(s):  
Surface Layer ◽  
Bearing Capacity ◽  
Asphalt Pavement ◽  
Structure Design ◽  
Urban Agglomeration ◽  
Central Plains ◽  
Rainfall Characteristics ◽  
Combination Scheme ◽  
Pavement Structure ◽  
Pavement Structures

Abstract Permeable asphalt pavement should be selected according to the rainfall characteristics of the project site, so as to improve the permeable performance and ensure the bearing capacity of the pavement structure. Therefore, taking a city in the central plains urban agglomeration of China as an example, the characteristics of the rainstorm intensity distribution and cumulative rainfall are analyzed, and a combination scheme of drainage surface layer asphalt pavement suitable for rainfall characteristics in this area is proposed. Then, the pavement structure design is systematically carried out based on the permeable capacity and bearing capacity. The results show that under the rainfall conditions in this area, there is no surface runoff on the permeable asphalt pavement with 120 mm drainage surface layer, which is suitable for the medium traffic grade of urban roads with cumulative equivalent axle loads of 10 million to 12 million times.

Application of Semi-analytical Method in Transient Thermal Field of Pavement Structures

2011 ◽  
Vol 105-107 ◽  
pp. 1289-1294
Author(s):  
Fu Liang Mei ◽  
Gui Ling Li
Keyword(s):  
Heat Conduction ◽  
Daily Temperature ◽  
Crack Control ◽  
Temperature Changes ◽  
Hourly Temperature ◽  
Control And Prevention ◽  
Different Depths ◽  
Pavement Structure ◽  
Pavement Structures ◽  
Transient Thermal

The daily temperature change of a pavement structure has an important impact on its crack production and propagation. First of all, a one-dimensional transient mathematical model of heat conduction and a heat convection boundary condition that can take solar radiation and ground radiation into account were established according to the characters of the pavement structure and heat conduction. Secondly all the computational formulae were deduced for the above model utilizing SAM. Finally, the hourly temperature field of a typical pavement structure was calculated using ANSYS and SAM respectively. Results show that SAM solutions at different depths are in good line with ANSYS solutions. Therefore, SAM is an easy-programmed, fast and high precise method, and is deserve to be popular. In addition, the daily temperature changes at different depths were discussed, and some suggestions were provided for the thermal crack control and prevention of the structure

scholarly journals Design solutions for pavements structure affected by static and impact load

2014 ◽  
Vol 9 (4) ◽  
pp. 269-275 ◽  
Author(s):  
Audrius Vaitkus ◽  
Viktoras Vorobjovas ◽  
Judita Gražulytė ◽  
Rita Kleizienė ◽  
Ovidijus Šernas ◽  
...  
Keyword(s):  
Impact Load ◽  
Climatic Conditions ◽  
Waste Utilization ◽  
Structure Design ◽  
Pavement Performance ◽  
Impact Loads ◽  
Main Factors ◽  
Pavement Structure ◽  
Pavement Structures ◽  
In The Beginning

Pavements of aprons, container and logistic terminals, areas of storage, parking lots, areas of waste utilization are affected by high pressure static and impact loads. These loads strongly influence pavement performance by causing permanent deformations and distresses in the surface and even sometimes pavement failure in the beginning of pavement service. The types of structure, materials and layer thicknesses are the main factors relative to pavement performance. In order to correctly understand the particularity of static and impact loading, distresses of pavement structures affected by such load are emphasized, the load specification and climatic conditions influencing pavement performance are characterized. After analysis of the best practise, the flow chart of pavement structure design model was introduced. The paper gives reasonable pavement type and thickness determination dependent on object of application pavement structure.

scholarly journals Viastructura – A New Way Of Pavement Structure Design

2021 ◽  
Vol 1202 (1) ◽  
pp. 012018
Author(s):  
Audrius Vaitkus ◽  
Rita Kleizienė ◽  
Martynas Karbočius
Keyword(s):  
Layer Thickness ◽  
Construction Materials ◽  
The United States ◽  
Structure Design ◽  
Test Results ◽  
Additional Function ◽  
Structure Selection ◽  
Laboratory Test Results ◽  
Pavement Structure ◽  
Pavement Structures

Abstract The catalogues of standard pavement structures are common way to design road pavements. In 2019, new regulation for the design of standard pavement structures KPT SDK 19 was issued in Lithuania. One of the new requirements require verification of layer thickness of high-class pavement structures. Such verification should be done by internationally approved mechanistic-empirical methods. In addition, it is recommended to use the same methods to adjust the layer thickness of the selected standard pavement structure for lower classes. These calculations are particularly applicable when the design load (ESAL) is at the lower or upper limit of the class range. Vilnius Tech Road Research Institute experts and outsource IT specialists spent two years for the design model ViaStructura development. Web software based on mechanistic-empiric approach include the boundary conditions, based on Austria, the United States and Germany experience and laboratory test results of construction materials. Materials can be selected from created database, which can be simply expanded with the new materials by the user. as Additional function allow comparison of separate designed pavement structures. The article present the concept of the ViaStructura model for the design of flexible pavement structures, reveals its main principles and advantages comparing to the pavement structure selection by the standard catalogue.

scholarly journals Long-Term Performance of Pavement Structures with Cold In-Place Recycled Base Course

2021 ◽  
Vol 16 (2) ◽  
pp. 48-65
Author(s):  
Audrius Vaitkus ◽  
Judita Gražulytė ◽  
Andrius Baltrušaitis ◽  
Jurgita Židanavičiūtė ◽  
Donatas Čygas
Keyword(s):  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Asphalt Pavements ◽  
Recycled Asphalt ◽  
Binding Agents ◽  
Pavement Structure ◽  
Pavement Structures ◽  
Base Course ◽  
Surface Distress ◽  
Foamed Bitumen

Properly designed and maintained asphalt pavements operate for ten to twenty-five years and have to be rehabilitated after that period. Cold in-place recycling has priority over all other rehabilitation methods since it is done without preheating and transportation of reclaimed asphalt pavement. Multiple researches on the performance of cold recycled mixtures have been done; however, it is unclear how the entire pavement structure (cold recycled asphalt pavement overlaid with asphalt mixture) performs depending on binding agents. The main objective of this research was to evaluate the performance of cold in-place recycled asphalt pavements considering binding agents (foamed bitumen in combination with cement or only cement) and figure out which binder leads to the best pavement performance. Three road sections rehabilitated in 2000, 2003, and 2005 were analysed. The performance of the entire pavement structure was evaluated in terms of the International Roughness Index, rut depth, and pavement surface distress in 2013 and 2017.

scholarly journals Maintenance Techniques for Cracks in Asphalt Layers

2021 ◽  
pp. 25-37
Author(s):  
M. S. Eisa ◽  
F. S. Abdelhaleem ◽  
V. A. Khater
Keyword(s):  
Failure Load ◽  
Asphalt Pavements ◽  
Water Intrusion ◽  
Small Depth ◽  
Major Stage ◽  
Maintenance Work ◽  
Different Depths ◽  
Maintenance Techniques ◽  
Pavement Structure

Treating cracks in asphalt pavements is a major stage of each maintenance work for engineers. The goal of any crack cure is to limit the water intrusion into underlying pavement structure layers. Such water infiltrates in to base layers of the pavement and may cause damage to the pavement structure. The previous studies focused on crack repairing materials and methods but not the bonding at the interface joint. In this study, the influence of the repairing materials and depth on the bonding at the interface joint using two repairing materials. Slabs were cast to simulate surface of road. Unlikely, slabs contain cracks in the middle of slab with different depths (35 mm, 50 mm, 70 mm). Consequently, these cracks were repaired with two methods; firstly, repairing them with RC+Sand and secondly, with Sika flex®-1a. The slabs were tested after being repaired to know the best method and depth. It has been concluded that slabs having cracks that have been repaired with RC+Sand increase failure load compared with empty cracks and cracks that have been repaired with Sika flex®-1a. Also, cracks with small depth that have been repaired with Sika flex®-1a increase failure load compared with empty cracks.

scholarly journals Unified Strength Model of Asphalt Mixture under Various Loading Modes

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 889 ◽  
Author(s):  
Chengdong Xia ◽  
Songtao Lv ◽  
Lingyun You ◽  
Dong Chen ◽  
Yipeng Li ◽  
...  
Keyword(s):  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Structure Design ◽  
Strength Model ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Direct Tension ◽  
Indirect Tension ◽  
Pavement Structure ◽  
Loading Modes

Although the rutting resistance, fatigue cracking, and the resistance to water and frost are important for the asphalt pavement, the strength of asphalt mixture is also an important factor for the asphalt mixture design. The strength of asphalt mixture is directly associated with the overall performance of asphalt mixture. As a top layer material of asphalt pavement, the strength of asphalt mixture plays an indispensable role in the top structural bearing layer. In the present design system, the strength of asphalt pavement is usually achieved via the laboratory tests. The stress states are usually different for the different laboratory approaches. Even at the same stress level, the laboratory strengths of asphalt mixture obtained are significantly different, which leads to misunderstanding of the asphalt mixtures used in asphalt pavement structure design. The arbitrariness of strength determinations affects the effectiveness of the asphalt pavement structure design in civil engineering. Therefore, in order to overcome the design deviation caused by the randomness of the laboratory strength of asphalt mixtures, in this study, the direct tension, indirect tension, and unconfined compression tests were implemented on the specimens under different loading rates. The strength model of asphalt mixture under different loading modes was established. The relationship between the strength ratio and loading rate of direct tension, indirect tension, and unconfined compression tests was adopted separately. Then, one unified strength model of asphalt mixture with different loading modes was established. The preliminary results show that the proposed unified strength model could be applied to improve the accurate degree of laboratory strength. The effectiveness of laboratory-based asphalt pavement structure design can therefore be promoted.

scholarly journals Development of a Full-Depth Wheel Tracking Test for Asphalt Pavement Structure: Methods and Performance Evaluation

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Hui Wang ◽  
Zepeng Fan ◽  
Jiupeng Zhang
Keyword(s):  
Performance Evaluation ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Single Layer ◽  
Test Method ◽  
Shanxi Province ◽  
Wheel Tracking Test ◽  
Pavement Structure ◽  
Pavement Structures ◽  
Wheel Tracking

The rutting performance of asphalt pavement structure relies on the high temperature properties of asphalt mixture as well as the pavement structure and thickness. In order to investigate the influence of the structure and thickness, a full-depth wheel tracking test is developed in this research by improving the conventional wheel tracking test apparatus. The newly proposed test method is capable of varying its load speed and load size, controlling its specimen temperature gradient, and simulating the support conditions of actual asphalt pavement. The full-depth wheel tracking test based rutting performance evaluation of different asphalt pavement structures indicates that it is not reasonable to explain the rutting performance of asphalt pavement structure from the point of view of single-layer asphalt mixture rutting performance. The developed full-depth wheel tracking test can be used to distinguish rutting performance of different asphalt pavement structures, and two of five typical asphalt pavement structures commonly used in Shanxi Province were suggested for use in practical engineering.

An Application of the Maximum Shear Strain Increment in Searching Sliding Surfaces

2013 ◽  
Vol 423-426 ◽  
pp. 1618-1622 ◽  
Author(s):  
Liu Yong Cheng ◽  
Jian Li ◽  
Shan Xiong Chen ◽  
Xiao Jie Chu
Keyword(s):  
Shear Strain ◽  
Least Squares Method ◽  
Limit Equilibrium ◽  
Quadratic Function ◽  
Strain Increment ◽  
Vertical Line ◽  
Sliding Surface ◽  
Maximum Shear Strain ◽  
Sliding Surfaces ◽  
Different Depths

A slope landslides generally at the place where the shear strain increment is the largest. This position is considered as the standard of defining sliding surfaces to assess the slope stability under the action of the foundation. A new method is proposed to determine the potential sliding surface, which is based on the largest shear strain increment. Firstly, the stress and strain in the slope were calculated by using the finite difference software-FALC3D. Secondly, a series of vertical line would be set in the calculating section. And then the discrete coordinates of the sliding surface, where the shear strain is largest on the vertical line, would be found through programming fish program. At last the position and shape of the sliding surface can be obtained through carrying on curve fitting of the discrete points by using the least squares method. The concept of this method is clear and can reflect the true form of the sliding surface through contrasting with the limit equilibrium method. Sliding surfaces of different depths and distances of slope are researched and a quadratic function is put forward which can describe the trends of glide direction. Three coefficients of the quadratic function were analyzed and the corresponding expression was obtained which can provide a reference to specification revision and engineering.

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