Combined model framework for asphalt pavement condition determination after flooding
05 Jul 2017-Transportation Research Record (Transportation Research Board of the National Academies)-Vol. 2639, Iss: 2639, pp 64-72
TL;DR: In this article, the problem of flooded pavement assessment was formulated as a combination of hydraulic and structural analyses and an interactive simulation was developed from the model and was made available on the web to users in the public domain.
Abstract: Flooding of pavements often causes damage that is invisible on the surface. A way to predict the condition of a pavement after flooding will be useful for agencies to make rational decisions about the need for closing a road to traffic or opening it up for cleaning and recovery work. In this study, the problem of flooded pavement assessment was formulated as a combination of hydraulic and structural analyses. A model was developed; it consisted of results from unsaturated hydraulic and layered elastic structural analyses. An interactive simulation was developed from the model and was made available on the web to users in the public domain. Simulations with the model showed significant impacts when subgrade layer moduli were below 50 MPa and layer thickness was less than 200 mm for the hot-mix asphalt (HMA) and less than 600 mm for the base. Axle loads exceeding 80 kN exacerbated damages and hazardous conditions. The time to reach conditions that will not lead to damage or failure within a short period of ...
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TL;DR: In this article, the authors confirm the significant structural damage that is caused by flooding on flexible pavements caused by rainwater, and propose a method to repair the damage caused by the flooding.
Abstract: Flood-induced moisture damage of flexible pavements is a serious concern for many road authorities. Reports from several studies confirm the significant structural damage that is caused by flooding...
11 citations
TL;DR: In this article, an analytical model for estimating the time to drain considering the unsaturated characteristics of pavement base material and calibration of the developed model based on a mechanistic approach which is relatively inexpensive.
Abstract: Providing adequate subsurface drainage feature in a pavement system to remove the infiltrated moisture in a minimum time is an important design consideration, which prevents the premature failure of the pavement system, and hence helps in achieving a significantly lower life-cycle cost. Various surface drainage measures are taken to minimize the ingress of moisture into the pavement gradually lose their efficiency with the aging of the pavement. The use of an appropriate open-graded aggregate course as a drainage layer in the pavement is the best way to minimize the time for which the pavement materials are exposed to saturated conditions. The current drainage guidelines have been developed on the basis of moisture flow under saturated condition. A better understanding and estimation of moisture movement in a drainage layer can only be achieved by using seepage analysis that adopts the principles of saturated as well as unsaturated flow conditions. State-of-art of mathematical tools such as finite difference and FEA methods permits a rigorous solution of Richard’s equation for saturated and unsaturated moisture flow in a porous medium, the only major drawback is the need for rigorous modeling and computational tool for the simulations and the design of the drainage layer. This paper focuses on the development of an analytical model for estimating the time to drain considering the unsaturated characteristics of pavement base material and calibration of the developed model based on a mechanistic approach which is relatively inexpensive. The applicability of the approach is explained by using the four-standard aggregate gradations recommended by AASHTO for the drainage layer, as well as a dense graded aggregate layer, and the results are compared with those from the FHWA approach and finite element analysis. The study shows that the developed model performs as good as the finite element analysis, which requires rigorous numerical modeling, predicts drainage times that are significantly different from those obtained from the FHWA analysis, and that it is sensitive to key significant design parameters. Hence, the proposed model is recommended for regular use for the design of the drainage layer and for a parametric study of the complete drainage process.
9 citations
TL;DR: Wang et al. as discussed by the authors adopted the crack prediction model in the newly developed pavement design method named pavement ME Design (PMED) and the modified grey predictive model (GM (1, 1)) to predict the transverse crack of asphalt pavement in permafrost regions.
Abstract: Reliable transverse crack prediction can benefit the design and maintenance and improve the reliability of field investigation for asphalt pavement in permafrost regions of Qinghai-Tibet plateau. This study adopted the crack prediction model in the newly developed pavement design method named Pavement ME Design (PMED) and the modified grey predictive model (GM (1, 1)) to predict the transverse crack of asphalt pavement in permafrost regions. The complementary advantages for the two models based on the weight distribution theory were discussed, and a combined prediction model (PME-DGM combination model) taking account into region characteristics was developed. Finally, the applicability of combined prediction model was analyzed. The result showed that, the predictive accuracy of PME-DGM combination model established by the error sum of squares reciprocal method was the highest, the best weight allocations for each sub-model were LNCH = 0.601 and LDGM = 0.399, and the combination model can be applied in the permafrost region involved in this paper; The combination model is more appropriate in predicting the development trend of transverse crack of project-level asphalt pavement in permafrost regions; For PMED predictive model, this study raised a modified method base on a third-party model (DGM (1,1), and the result showed that the method worked well in the permafrost region of Qinghai-Tibet plateau.
8 citations
TL;DR: The infiltration of water from precipitation through the hot mix asphalt layers in flexible pavements can lead to significant decrease in the moduli of the underlying layers, especially the base layer.
Abstract: The infiltration of water from precipitation through the hot mix asphalt layers in flexible pavements can lead to significant decrease in the moduli of the underlying layers, especially the base la...
6 citations
Cites background from "Combined model framework for asphal..."
...provided some guidelines on the critical values of these key parameters and introduced the concept of critical time that the pavement needed to regain its pre-flooding structural capacity (10)....
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...modeled a three-layer pavement structure, composed of hot mix asphalt (HMA) surface layer, aggregate base, and natural subgrade, subject to flooding conditions (10)....
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...A comprehensive framework to combine the hydraulic and structural analyses does not exist (10, 11)....
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TL;DR: In this article , the authors developed a methodological framework to model postflooding road damage by identifying the importance of several parameters including flood duration, flood depth, flood pattern (including real flood data), transfer functions, pavement materials, and analysis location.
Abstract: The first step toward building pavement structures that are resilient to flooding is to have a proper understanding of the impact of inundation on the pavement. Depth-damage functions have been developed and are widely used to quantify flood-induced damage to buildings. However, such damage functions do not exist for roadway pavements. The objective of this study is to develop a methodological framework to model postflooding road damage by identifying the importance of several parameters including flood duration, flood depth, flood pattern (including real flood data), transfer functions, pavement materials, and analysis location. Pavement serviceability and costs are introduced into the evaluation as well. The long-term goal is a tool for decision makers to use in planning and management of flooding events for more resilient pavements and allocation of budgets. It is established that the most important parameters that should be accounted for by decision makers are the flood duration, combination of the materials, critical location on the roadway (both vertical and lateral), and use of appropriate transfer functions. Opening the roadway to traffic immediately after the floodwater recedes will lead to earlier and more significant deterioration of the pavement and more costly maintenance and reconstruction.
2 citations
References
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31 Dec 1963
5,311 citations
"Combined model framework for asphal..." refers methods in this paper
...In MNDrain, the Brooks–Corey models (11) are used to represent the relationship between the hydraulic conductivity (Equation 1) and pressure or moisture content and the relationship between the pressure and the moisture content (Equation 2):...
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TL;DR: In this article, the falling weight deflectometer (FWD) tests were performed every 161 m (0.1 mi ) over each selected roadway, along with other field tests.
Abstract: In September of 2005, Hurricane Katrina devastated New Orleans and caused sustained flooding. Limited pre- and postflooding tests indicated that the pavement structures tested were adversely impacted by the flood water. Consequently, the Louisiana Dept. of Transportation and Development hired an independent contractor to structurally test approximately 383 km ( 238 mi ) of the region’s federally aided urban highway system both inside and outside of the flooding area. Falling weight deflectometer (FWD) tests were performed every 161 m ( 0.1 mi ) over each selected roadway, along with other field tests. The FWD data were imported into a geographical information system and plotted against a USGS geo-referenced map. Comparative analyses were made possible through the use of extensive flood maps made available through NOAA and FEMA. This arrangement made it possible to classify spatially and graphically all test points on the basis of flooding versus nonflooding, short flooding duration versus longer flooding ...
73 citations
Additional excerpts
...DF predicted surface deflection, m 500 (4)...
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Journal Article•
TL;DR: A semi-mechanistic, semi-empirical analysis technique has been developed in South Africa in terms of which deflection bowl parameters, measured with the FWD, are used in a relative benchmarking methodology in conjunction with standardised visual survey methodology to give guidance on individual layer strengths and pinpoint rehabilitation needs.
Abstract: The falling weight deflectometer (FWD) is used worldwide as an established, valuable, nondestructive road testing device for pavement structural analyses. The FWD is used mostly for rehabilitation project level design investigations and for pavement management system (PMS) monitoring on a network basis. In project level investigations, design charts based on both empirical relations and mechanistic or theoretically based approaches are often used to provide structural evaluations and rehabilitation options. The full mechanistic approach normally uses multi-layer linear elastic theory and back-calculation procedures that have come under scrutiny owing to the inaccuracy of results. A semi-mechanistic, semi-empirical analysis technique has been developed in South Africa in terms of which deflection bowl parameters, measured with the FWD, are used in a relative benchmarking methodology in conjunction with standardised visual survey methodology to give guidance on individual layer strengths and pinpoint rehabilitation needs. This benchmark methodology enables the determination of the relative structural condition of the pavement over length and in depth without the requirement for detailed as-built data. A further correlation study with calculated surface moduli and deflection bowl parameters is presented here for granular base pavements, which can enhance benchmarking methodology.
68 citations
"Combined model framework for asphal..." refers background in this paper
...Surface deflection is an ideal performance indicator because (a) failure by excessive deflection can be catastrophic, (b) it has been related to condition of pavements (8, 9), and (c) if needed, it can be determined relatively easily with a falling weight deflectometer without backcalculation of moduli....
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...DF and SF are defined in Equations 4 and 5, respectively (8, 9):...
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Journal Article•
TL;DR: A semi-mechanistic, semi-empirical analysis technique has been developed in South Africa in terms of which deflection bowl parameters, measured with the falling weight deflectometer, are used in a relative benchmarking methodology in conjunction with standardised visual survey methodology to give guidance on individual layer strengths and pinpoint rehabilitation needs.
Abstract: The falling weight deflectometer (FWD) is used worldwide as an established, valuable, nondestructive road testing device for pavement structural analyses. The FWD is used mostly for rehabilitation project level design investigations and for pavement management system (PMS) monitoring on a network basis. In project level investigations, design charts based on both empirical relations and mechanistic or theoretically based approaches are often used to provide structural evaluations and rehabilitation options. The full mechanistic approach normally uses multi-layer linear elastic theory and back-calculation procedures that have come under scrutiny owing to the inaccuracy of results. A semi-mechanistic, semi-empirical analysis technique has been developed in South Africa in terms of which deflection bowl parameters, measured with the FWD, are used in a relative benchmarking methodology in conjunction with standardised visual survey methodology to give guidance on individual layer strengths and pinpoint rehabilitation needs. This benchmark methodology enables the determination of the relative structural condition of the pavement over length and in depth without the requirement for detailed as-built data. A further correlation study with calculated surface moduli and deflection bowl parameters is presented here for granular base pavements, which can enhance benchmarking methodology.
55 citations