Structural pavement responses using nonlinear finite element analysis of unbound materials

Loizos, Andreas; Spiliopoulos, Konstantinos; Cliatt, Brad; Gkyrtis, Konstantinos

doi:10.1201/9781315100333-178

Cited by 7 publications

(3 citation statements)

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“…In terms of the pavement surface, the most impactful parameter is the skid resistance, or the frictional force that develops in the tire-pavement area. Provided that adequate construction quality has been achieved for pavement layers and materials [53,54], the focus is usually being put on the functionality of the pavement [55]. Less vehicle stops correspond to non-zero speeds, thereby rutting, shoving, or other severe distresses, typically observed at simple intersections, tend to be absent provided that shear-resistant asphalt mixtures are properly designed.…”

Section: Pavement Conditionmentioning

confidence: 99%

An Overview of the Efficiency of Roundabouts: Design Aspects and Contribution toward Safer Vehicle Movement

Gkyrtis,

Kokkalis

2024

Vehicles

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Transforming intersections into roundabouts has shown that a sufficient degree of road safety and traffic capacity can be achieved. Because of the lower speeds at the area of a roundabout, drivers tend to become more easily adaptive to any kind of conflict with the surrounding environment. Despite the contribution to safety, the design elements of roundabouts are not uniformly fixed on a worldwide scale because of different traffic volumes, vehicle dimensions, drivers’ attitude, etc. The present study provides a brief overview of the contribution of roundabouts to road safety and the interactions between safety and the design elements of roundabouts. In addition, discussion points about current challenges and prospects are elaborated, including findings from the environmental assessment of roundabouts; their use and performance on the era of autonomous vehicles that will dominate in the near future; as well as the role and importance of simulation studies towards the improvement of the design and operation of roundabouts in favor of safer vehicle movement. The criticality of roundabouts, in terms of their geometric design as well as the provided road safety, lies upon the fact that roundabouts are currently used for the conventional vehicle fleet, which will be gradually replaced by new vehicle technologies. Such an action will directly impact the criteria for road network design and/or redesign, thereby continuously fostering new research initiatives.

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Section: Pavement Conditionmentioning

confidence: 99%

An Overview of the Efficiency of Roundabouts: Design Aspects and Contribution toward Safer Vehicle Movement

Gkyrtis,

Kokkalis

2024

Vehicles

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“…In this study, input values for thicknesses and moduli are based on current experience from pavement design and construction such that they cover a wide spectrum of relevant practices in pavement engineering. The mechanistic behavior of the unbound materials is considered through a User-defined MATerial subroutine (UMAT), as was presented and validated in [33]. The impact of the analysis type on the predicted responses is outlined in terms of quantification of variations, to assist pavement design optimization and enhance performance prediction of existing structures.…”

Section: Study's Objectivementioning

confidence: 99%

Pavement Analysis with the Consideration of Unbound Granular Material Nonlinearity

Gkyrtis

2023

Designs

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Accurate pavement design and evaluation requires the execution of response analysis. Pavement materials’ behavior does not necessarily conform to the assumptions of the multi-linear elastic theory usually adopted during pavement analysis. In particular, the unbound granular materials located in the base and sub-base layers behave in a nonlinear elastic manner, which can be captured through advanced constitutive modeling of their resilient modulus. The finite element method enables us to code constitutive models and quantify potential variations in pavement responses because of different mechanistic assumptions. In this study, variations in response are investigated for a typical structure of a flexible pavement considering the nonlinear anisotropic behavior of the unbound materials together with their initial stress–strain state. To demonstrate the impact of their behavior on the outcome of pavement analysis, variable asphalt concrete layer thicknesses and moduli are assumed, such that they cover a large spectrum of roadways. It was found that pavement responses can be calculated up to 3.5 times higher than those retrieved from the conventional linear analysis. This comparison means that the alterative mechanistic modeling of the unbound granular materials can be proved to be more conservative (i.e., leading to higher strains) in terms of pavement design and analysis. From a practical perspective, this study alerts pavement scientists and engineers engaged in pavement design to a more reliable performance prediction, which is needed to bridge the gap between advanced modeling and routine analysis.

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“…Since the less expensive RA binder can replace a portion of the more expensive virgin binder, the use of RA binder is economical and may also help to reduce a set of environmental burdens [2,7,8]. With the rapid rise of asphalt prices [9], there have been several research efforts made towards maximizing the quantity of RAP used in the production of recycled asphalt mixtures (RAM) [10][11][12][13]. Many successful applications incorporating high RAP content have proved the great potential of RAP in road construction [1,[14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Impact of Preheating Temperatures and RAP Characteristics on the Activation of RAP Binder

Meng

Liu

2020

Applied Sciences

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Reclaimed asphalt pavement (RAP) is preheated to 120 °C or lower in hot central plant recycling due to specification and equipment limitations. However, the insufficient activation of reclaimed asphalt (RA) caused by low preheating temperature may affect the final properties of reclaimed asphalt mixtures (RAM) and lead to insufficient utilization of RA binder. This study evaluated the influence of preheating temperature and aging of RA binder on binder activation by producing specimens with 100% RAP. The volumetric and mechanical properties of specimens were analyzed to reflect the effect of activation. The results indicate that preheating temperature has a significant impact on the activation of RA binder. Regardless of the source of RAP, RA binder can be highly activated at 180 °C, while the degree of activation decreases significantly at 120 °C. By using an artificial RAP with different degrees of aging, the aging of RA binder is found to be harmful to activation only when the preheating temperature is low (such as 120 °C). Hence, if the equipment is capable of doing so, it is better to raise the preheating temperature of RAP to improve the activation of RA binder, especially for binder with a higher degree of aging.

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Structural pavement responses using nonlinear finite element analysis of unbound materials

Cited by 7 publications

References 0 publications

An Overview of the Efficiency of Roundabouts: Design Aspects and Contribution toward Safer Vehicle Movement

An Overview of the Efficiency of Roundabouts: Design Aspects and Contribution toward Safer Vehicle Movement

Pavement Analysis with the Consideration of Unbound Granular Material Nonlinearity

Impact of Preheating Temperatures and RAP Characteristics on the Activation of RAP Binder

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