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.

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.

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 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.

scholarly journals Influence of asphalt visco-elastic properties on flexible pavement performance

2016 ◽  
Vol 11 (4) ◽  
pp. 313-323 ◽  
Author(s):  
Rita Kleizienė ◽  
Audrius Vaitkus ◽  
Donatas Čygas
Keyword(s):  
Elastic Properties ◽  
Asphalt Mixture ◽  
Pavement Design ◽  
Pavement Performance ◽  
Elastic Behaviour ◽  
Main Challenge ◽  
Complex Shear ◽  
Pavement Structure ◽  
Pavement Structures

Even though every layer of pavement structure is important and affects pavement performance, the asphalt layers visco-elasticity plays significant role. Bitumen properties, as well as asphalt mixture properties, vary depending on temperature and loading conditions. These variations influence entire pavement bearing capacity and has to be evaluated in pavement design. The main challenge is material behaviour description through simple models to incorporate them to pavement design. Generally, pavements are designed using Multilayer Elastic Theory assuming that all materials are elastic, isotropic, and homogenous. This paper presents analysis of two pavement structures response calculated according to three pavement design approaches. The dynamic modulus and phase angle of asphalt mixtures was estimated using Hirsch model after binder complex shear modulus tests. The visco-elastic behaviour was described with rheological Huet-Sayegh model and pavement responses estimation was done using MnLayer and ViscoRoute2 software. The analysis reviled static and dynamic load influence on pavement structure based on elastic and visco-elastic properties of asphalt layers. This allowed optimisation of layer thicknesses and determination of more cost beneficial pavement structure with appropriate performance.

scholarly journals Comparison of the Bearing Capacity of Pavement Structures with Unbound and Cold Central-Plant Recycled Base Courses Based on FWD Data

2021 ◽  
Vol 13 (11) ◽  
pp. 6310
Author(s):  
Audrius Vaitkus ◽  
Judita Gražulytė ◽  
Igoris Kravcovas ◽  
Rafal Mickevič
Keyword(s):  
Bearing Capacity ◽  
Water Content ◽  
Early Spring ◽  
Pavement Performance ◽  
Aggregate Gradation ◽  
Central Plant ◽  
Negative Effect ◽  
Pavement Structure ◽  
Pavement Structures ◽  
Base Course

Bearing capacity changes over the year, depending on the water content in a pavement structure: the higher the water content, the lower the bearing capacity. As expected, the highest water content in a pavement structure is observed in the early spring as the ice lenses melt. Thus, spring is a critical period for pavement performance, because a decrease in bearing capacity results in faster pavement deterioration. The bearing capacity of pavement structures with an unbound base course and the negative effect of spring thawing on pavement performance have been analyzed by a considerable number of researchers. However, very little is known about the bearing capacity of pavement structures with a cold-recycled base course despite the significantly increasing usage of cold-recycled mixtures. This paper focuses on the bearing capacity of both unbound and cold central-plant recycled base courses at different seasons and their stability. A cold central-plant recycled (CCPR) base course was constructed from a mixture of 38.8% reclaimed asphalt pavement (RAP), 3.1% foamed bitumen and 2.3% cement. A virgin aggregate was added to achieve desirable aggregate gradation. The bearing capacity of the unbound and CCPR base layers, as well as the whole pavement structure, was evaluated by back-calculated E moduli from falling weight deflectometer (FWD) data. In addition to this, the residual pavement life was calculated using mechanistic-empirical pavement design principles. The results showed that the durability of pavement structures with a CCPR base course is more than seven times lower compared to that of pavement structures with an unbound base course, irrespective of season. Nevertheless, the bearing capacity (surface modulus E0) of the pavement structure with a CCPR base course gradually increases due to the curing processes of bituminous and hydraulic binders (in this study, within four years of operation, it increased by 28–47%, depending on the side of the road).

Пригодность очищенного картофеля к вакуумной упаковке и быстрой заморозке

2018 ◽  
Author(s):  
S.V. Maltsev
Keyword(s):  
Potato Variety ◽  
Climatic Conditions ◽  
Vacuum Packaging ◽  
Mineral Fertilizers ◽  
Main Factors ◽  
Fast Freezing

Отражены результаты исследования основных факторов (сорт, почвенно-климатические условия выращивания, фон минерального питания, температура хранения сырья и готового продукта, срок переработки), определяющих пригодность картофеля к вакуумной упаковке и быстрой заморозке без применения консервантов.The article reveals main factors (such as potato variety, soil and climatic conditions, doses of mineral fertilizers, store temperatures, different timelines of processing) determining the suitability of potatoes for vacuum packaging and fast freezing without usage of chemicals.

Use of Long-Term Pavement Performance Data to Develop Traffic Defaults in Support of Mechanistic-Empirical Pavement Design Procedures

2003 ◽  
Vol 1855 (1) ◽  
pp. 176-182 ◽  
Author(s):  
Weng On Tam ◽  
Harold Von Quintus
Keyword(s):  
Pavement Design ◽  
Vehicle Classification ◽  
Pavement Performance ◽  
Traffic Data ◽  
Design Procedures ◽  
Load Spectra ◽  
State Highway ◽  
Pavement Structures ◽  
Empirical Design

Traffic data are a key element for the design and analysis of pavement structures. Automatic vehicle-classification and weigh-in-motion (WIM) data are collected by most state highway agencies for various purposes that include pavement design. Equivalent single-axle loads have had widespread use for pavement design. However, procedures being developed under NCHRP require the use of axle-load spectra. The Long-Term Pavement Performance database contains a wealth of traffic data and was selected to develop traffic defaults in support of NCHRP 1-37A as well as other mechanistic-empirical design procedures. Automated vehicle-classification data were used to develop defaults that account for the distribution of truck volumes by class. Analyses also were conducted to determine direction and lane-distribution factors. WIM data were used to develop defaults to account for the axle-weight distributions and number of axles per vehicle for each truck type. The results of these analyses led to the establishment of traffic defaults for use in mechanistic-empirical design procedures.

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 Impact Resistance Analysis and Optimization of Variant Truss Beam Structure Based on Material Properties

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5847
Author(s):  
Xiaohao Li ◽  
Junqi Pan ◽  
Xingchen Zhou
Keyword(s):  
Simulation Analysis ◽  
Impact Load ◽  
Impact Resistance ◽  
Structure Design ◽  
Response Surfaces ◽  
Optimization Strategy ◽  
Buffer Effect ◽  
Characteristic Analysis ◽  
Beam Structure ◽  
The Impact

In order to meet the increasing application requirements with regards to structural impact resistance in industries such as mining, construction, aerospace engineering, and disaster relief and mitigation, this paper designs a variant truss beam structure with a large shrinkage ratio and high impact resistance. Based on the principle of the curved trajectory of scissor mechanisms, this paper conducts a finite element simulation analysis of the impact load on the truss beam structure, a theoretical analysis of the impact response and a relevant prototype bench-top experiment, completing a full study on the impact resistance mechanism of the designed variant truss beam structure under the impact load. In the paper, the buffer effect of the external load impact on the variant truss beam structure is analyzed from the perspective of the energy change of elastic–plastic deformation. This paper proposes an optimization strategy for the variant truss beam structure with the energy absorption rate as the optimization index through extensive analysis of the parameter response surfaces. The strategy integrates analyses on the response characteristic analysis of various configuration materials to obtain an optimal combination of component parameters that ensures that the strength of the truss beam structure meets set requirements. The strategy provides a feasible method with which to verify the effectiveness and impact resistance of a variant truss structure design.

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