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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TL;DR: In this paper, a system dynamics-based methodology was developed to determine the critical time (Tcritical) for full saturation of the unbound base and for failure of the bound surface layer.
Abstract: Proper assessment of flooded pavement is very critical for reducing the risk and ensuring the safety of construction crews, department of transportation personnel and the public. The objective of this paper is to present a rational procedure for the assessment of vulnerability of asphalt pavements to flood-induced damage. A system dynamics-based methodology was developed to determine the critical time (Tcritical) for full saturation of the unbound base and for failure of the bound surface layer. The methodology and the web-based simulation tool presented here will help the users to identify potentially vulnerable stretches of highway prior to flooding and either take action to improve them or monitor them closely to obtain preflood conditions which can be compared against post-flood conditions to detect deterioration; it will help them decide whether emergency and non-emergency vehicles can be allowed during and immediately after flooding, and in planning post-flooding investigative actions.
34 citations
"Combined model framework for asphal..." refers background in this paper
...Determination of whether the base is saturated or not and a model to simulate the different conditions, such as duration and depth of flooding, have been formulated and presented elsewhere (7)....
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01 Mar 2007
TL;DR: Fugro et al. as mentioned in this paper conducted pavement testing on several on-going construction projects that were submerged to determine if contract modifications would be necessary to address damage impact, and found that the damage incurred was equivalent to three inches of asphalt concrete.
Abstract: On August 29, 2005, Hurricane Katrina devastated New Orleans and southeastern Louisiana, leaving hundreds of thousands either displaced or homeless. Nearly four weeks later, Hurricane Rita made landfall in the southwestern portion of the state, further damaging Louisiana's infrastructure and impacting the New Orleans area. In response, LTRC personnel conducted pavement testing on several on-going construction projects that were submerged to determine if contract modifications would be necessary to address damage impact. Damage was found in asphalt and concrete layers, and subgrades were found to be very weak. For one project, LA 46, LTRC had "before and after" data which indicated that the damage incurred was equivalent to three inches of asphalt concrete. As a result, Louisiana Department of Transportation and Development (LaDOTD) contracted with Fugro Consultants, LP, to conduct testing on 238 mi of state highways in new Orleans at 0.1 mi intervals. Fugro conducted falling Weight Deflectometer, Ground Penetrating Radar, and Dynamic Cone Penetrometer testing along with coring selected locations for thickness and damage verification to determine the extent of structural damage to these pavements. Because there was no "before" data, a traditional forensic type analysis could not be undertaken. With the use of global information system (GIS) mapping and the National Oceanographic and Atmospheric Association (NOAA) flood mapping, data points could be identified as either submerged or non-submerged. The non-submerged data were then considered as a control set, and the submerged data were considered as the experimental set. In this manner, the data could be tested using standard analysis of variance techniques to test the hypothesis that the submerged pavements were weaker and therefore damaged as a result of the hurricanes. It is noted that this methodology does not imply that the non-submerged pavements were not damaged also, but provides a relative damage estimate. Once weaker strength parameters were determined, standard pavement design methods were applied to the structural numbers and subgrade modulii to determine an equivalent amount of asphalt concrete for this strength loss. In general, it was found that asphalt pavements had strength loss equivalent to about two inches of new asphalt concrete and that thinner asphalt pavements were weaker than the thicker pavements. Very little relative damage was detected for the portland cement concrete (PCC) pavements. The composite pavements demonstrated no need for additional structure in the pavement layers; however a weaker subgrade for the submerged areas equivalent to nearly one inch of asphalt concrete was identified. Using recent bid prices in New Orleans of $250,000 per mile for a typical rehabilitation scenario (mill four inches/replace four inches of asphalt concrete), an estimated cost for the approximately 200 mi of submerged state highway pavements would be $50 million. There are another 300 mi of federal-aid and 1500 mi of non-federal aid roads that were submerged in the New Orleans area.
32 citations
"Combined model framework for asphal..." refers background in this paper
...Quite often flooding results in deterioration or weakening of pavement layers (temporary or long term), and such damage may not be visible on the surface, since the major effect of water is on unbound layers below the bound surface, which is typically hot-mix asphalt (HMA) (1, 2)....
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01 Sep 2013
TL;DR: The 2011 Missouri River flooding caused significant damage to many geo-infrastructure systems including levees, bridge abutments/foundations, paved and unpaved roadways, culverts, and embankment slopes in western Iowa.
Abstract: The 2011 Missouri River flooding caused significant damage to many geo-infrastructure systems including levees, bridge abutments/foundations, paved and unpaved roadways, culverts, and embankment slopes in western Iowa. The flooding resulted in closures of several interchanges along Interstate 29 and of more than 100 miles of secondary roads in western Iowa, causing severe inconvenience to residents and losses to local businesses. The main goals of this research project were to assist county and city engineers by deploying and using advanced technologies to rapidly assess the damage to geo-infrastructure and develop effective repair and mitigation strategies and solutions for use during future flood events in Iowa. The research team visited selected sites in western Iowa to conduct field reconnaissance, in situ testing on bridge abutment backfills that were affected by floods, flooded and non-flooded secondary roadways, and culverts. In situ testing was conducted shortly after the flood waters receded, and several months after flooding to evaluate recovery and performance. Tests included falling weight deflectometer, dynamic cone penetrometer, three-dimensional (3D) laser scanning, ground penetrating radar, and hand auger soil sampling. Field results indicated significant differences in roadway support characteristics between flooded and non-flooded areas. Support characteristics in some flooded areas recovered over time, while others did not. Voids were detected in culvert and bridge abutment backfill materials shortly after flooding and several months after flooding. A catalog of field assessment techniques and 20 potential repair/mitigation solutions are provided in this report. A flow chart relating the damages observed, assessment techniques, and potential repair/mitigation solutions is provided. These options are discussed for paved/unpaved roads, culverts, and bridge abutments, and are applicable for both primary and secondary roadways.
28 citations
Additional excerpts
...SF 750 m predicted surface deflection (5)...
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01 Jan 2008
TL;DR: In this paper, a study performed to assess the extent of damage to JP's road pavements caused by the hurricanes is described, which involved selecting a study area with a total length of 338 miles and using a Design of Experiment (DOE).
Abstract: In 2005, Louisiana was hit by Hurricanes Katrina and Rita, causing devastating damage to its infrastructure. Due to the hurricanes, part of Jefferson Parish’s (JP's) road network was submerged under water for weeks and other parts were subject to unusually heavy traffic loading. As such, the pavements, although appearing unaffected, may be suffering from undetected damage in the roadbed soils that could result in failures at a time when emergency federal funds are no longer available. This paper describes a study performed to assess the extent of damage to JP’s road pavements caused by the hurricanes. The study involved selecting a study area with a total length of 338 miles, which represents approximately 20% of JP's road network, using a Design of Experiment (DOE); estimating the pre-Katrina/Rita pavement conditions; evaluating the post-Katrina/Rita pavement conditions; and analyzing of pavement damage. JP has had a comprehensive Pavement Management System (PMS) since 1996. The PMS database included historical roughness, distress, deflection and traffic data, which played a vital role in this study. The PMS was used to estimate the pre-hurricane pavement condition in terms of roughness, distresses and deflection. Extensive field testing, including roughness, distresses, deflection, and coring/boring, was conducted to evaluate the post-hurricane conditions. Backcalculation and advanced deflection basin analyses were used to assess the structural integrity of the pavement structure and subgrade. The pavement damage analysis involved before-and-after roughness, distress, and structural analyses, as well as statistical analysis (e.g., ANOVA) to test the extent and significance of the damage.
25 citations
09 Jul 2007
TL;DR: A semi-mechanistic semi-empirical analysis technique has been developed in South Africa whereby deflection bowl parameters, measured with the falling weight Deflectometer (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 as discussed by the authors.
Abstract: A semi-mechanistic semi-empirical analysis technique has been developed in South Africa whereby deflection bowl parameters, measured with the falling weight Deflectometer (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 benchmarking methodology can be enhanced by the use of calculated surface moduli based on the use of Boussinesq’s equations. The calculation of such surface moduli can be enhanced by determining the gradient of the surface moduli as correlated with the subgrade layer and the elastic response characteristics. Such benchmark calculations are done without complicated and detailed multi-layered linear elastic modelling and software and enables the determination of the relative structural condition of the pavement without detailed as-built data being required.
9 citations