The Guide for Design of Pavement Structures (AASHTO 86/93) and Mechanistic Empirical Pavement Design Guide (MEPDG) are two common methods to design continuously reinforced concrete pavement (CRCP) published by the American Association of State Highway and Transportation Officials (AASHTO) in the USA. The AASHTO 86/93 is based on empirical equations to assess the performance of highway pavements under moving loads with known magnitude and frequency derived from experiments on AASHTO road tests. The MEPDG is a pavement design method based on engineering mechanics and numerical models for analysis. It functions by incorporating additional attributes such as environment, material properties, and vehicle axle load to predict pavement performance and degradation at the selected reliability level over the intended performance period. In order to evaluate the CRCP design procedure and performance, crack width (CW) and crack spacing (CS) from five examined test tracks in Europe with different climate condition, base layer, geometry, and materials were collected in this paper and compared with predicted distresses as well as CW and CS from AASHTO 86/93 and MEPDG design methods. The results show that the interactions between geometrics, material properties, traffic, and environmental conditions in the MEPDG method are more pronounced than in the AASHTO 86/93 and the prediction of CS and CW based on MEPDG matched closely with the recorded data from sections.
Variations in pavement density have been widely monitored and investigated, both in laboratory and in field experiments, since the compaction of pavement is so critical to its long-term performance quality. In contrast to field testing, laboratory tests are simpler to produce but less accurate. Destructive drilled samples are used to conduct field testing; however, they are limited in their ability to assess density information at specific areas. The use of computationally aided approaches, such as the Finite Element Method (FEM) and the Discrete Element Method (DEM), in research involving asphalt mixtures is increasing, since these methods simulate and evaluate the characteristics of asphalt mixtures at macroscopic and microscopic scales. Individual particle behavior at the microscopic level cannot be fully represented using the FEM alone, and the computing cost of utilizing the DEM approach alone is prohibitively high. The objective of this work is to simulate the pre-compaction process by using the coupled FEM-DEM approach. In order to investigate the impact of the asphalt mixtures’ gradation, a dense-graded asphalt mixture (AC 11) and a gap graded asphalt mixture (PA 11) were simulated. Different paving speeds (4, 5, and 6 m/min) were applied on the preliminary compaction model of AC 11 to study the effect of the paving speeds on the compaction process. By comparing the angular velocity, which worked as a reference of compaction quality, it was demonstrated that the grade AC 11 asphalt mixtures performed better in the preliminary compaction process compared to the grade PA 11 asphalt mixtures. Moreover, since it has an effect on compaction, paving speed was carefully monitored and kept within a reasonable range in order to maximize both pavement quality and project efficiency.
Continuously reinforced concrete pavement (CRCP) is a representative type of concrete pavement constructed with continuous steel bars without intermediate transverse expansions. With reference to pavement conditions, CRCP is an exceptional type of concrete pavement according to the Highway Pavement Condition Index (HPCI) and International Roughness Index (IRI). The two main design methods for CRCP are AASHTO 86/93 and the Mechanistic–Empirical Pavement Design Guide (MEPDG). Because of limitations of the AASHTO 86/93 design method, the MEPDG method is more reliable. While incorporating the interactions among geometrics, pavement structure layers, material properties, subgrade, traffic, and environmental conditions, and the prediction values according to the MEPDG method, it matched the measured results of crack spacing and crack width. The MEPDG punchout, crack width and spacing, and load transfer efficiency (LTE) models were evaluated, and results were compared with the test sections in three European countries consisting of different construction details, which were investigated and recorded between 2019 and 2021. In this sense, a calculation tool was developed to consider the influence of different parameters in design process. In addition, sensitivity analyses were executed for the development of punchout, considering various input parameters. The track surveying and the evaluation of the results indicated that the design process can be improved with consideration of some criteria such as crack formation time or adjustment of the correlation between crack width and crack spacing. Due to the very important function of erosion and resulting pumping in the deterioration of CRCP, it is advisable to include the influence of the base layer and the influence of different shoulder type and heavy traffic volume or effect of deflection in the calculations.
The traffic volume and the amount of heavy traffic on German motorways increased steadily. To guarantee mobility and reduce the national economic costs, road construction with maximum service life, minimum maintenance and minimum traffic restrictions for maintenance are needed. Continuously reinforced concrete pavement (CRCP) are extremely durable in terms of use and maintenance. CRCP offer lower thickness, no transversal joints and the possibility to improve skid resistance and reduction of noise emissions through a thin asphalt surface. The performance of CRCP is influenced by a number of specific characteristics such as the thickness and the quality of the concrete, the longitudinal and transversal reinforcement, the base layer and the environmental conditions. These aspects influence the crack pattern, crack distance and crack widths. In Germany CRCP is in the stage of field testing. From 1997 to today, a total of 8 sections with many variations have been constructed. A detailed comparative study of these sections has been lacking. As part of a research project, the RWTH University and the German Federal Highway Research Institute (BASt) are investigating these sections in CRCP with and without an asphalt surface in Germany and compare it to the Belgium standard constructions. Three CRCP sections were selected and evaluated throughout Germany. The aim is to evaluate the different designs in the sections in terms of their behavior, to quantify achievable service life, necessary maintenance and availability. From this, a preferred variant of the construction is designed and implemented on a motorway in Germany as part of a trial site.
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