Calibration of Flexible Pavement Performance Equations for Minnesota Road Research Project

2003 ◽  
Vol 1853 (1) ◽  
pp. 134-142 ◽  
Author(s):  
David H. Timm ◽  
David E. Newcomb
Keyword(s):  
Field Performance ◽  
Calibration Procedure ◽  
Asphalt Pavements ◽  
Pavement Performance ◽  
Design System ◽  
Research Project ◽  
Pavement Distress ◽  
Performance Project

As mechanistic-empirical (M-E) pavement design gains wider acceptance as a viable design methodology, there is a critical need for a well-calibrated design system. Calibration of the pavement performance equations is essential to link pavement responses under load to observed field performance. A field calibration procedure for asphalt pavements that incorporates live traffic, environmental effects, observed performance, and in situ material characterization was developed. The procedure follows the M-E design process, iterating the transfer function coefficients until the performance equation accurately predicts pavement distress. Test sections from the Minnesota Road Research Project were used to demonstrate the calibration process, and fatigue and rutting performance equations were developed. It is recommended that further calibration studies be undertaken with this methodology, possibly by using sections from the Long-Term Pavement Performance project.

Performance evaluation of jointed plain concrete pavements with sealed and unsealed joints in North Texas

2019 ◽  
Vol 46 (7) ◽  
pp. 601-608
Author(s):  
Mena I. Souliman ◽  
Ashish Tripathi ◽  
Lubinda F. Walubita ◽  
Mayzan M. Isied
Keyword(s):  
Field Performance ◽  
Plain Concrete ◽  
Water Infiltration ◽  
Concrete Pavements ◽  
North Texas ◽  
Pavement Distress ◽  
Initial Cost ◽  
Additional Costs ◽  
Cost Of Construction

Joint sealing in jointed plain concrete pavement (JPCP) has been practiced throughout the world for many years as it improves the performance of concrete pavements. The infiltration of water is a common problem in concrete pavements and often increases distresses, such as faulting and pumping. For this reason, sealing the joints can help reduce water infiltration. Additionally, the infiltration of sand and small stones, aggregates, or debris into the joints can also be prevented, consequently reducing joint spalling in concrete pavements. However, it is also reported that joint sealing increases the initial cost of construction, especially if the joints need to be resealed, which leads to some additional costs. In this study, the pavement distress data was collected from the long-term pavement performance (LTPP) database for all the JPCPs sections in North Texas. The study illustrates the relative field performance in terms of spalling, faulting, roughness, and deflections of JPCP sections for both sealed and unsealed LTPP sections of North Texas.

Seed Modulus Generation Algorithm for Backcalculation of Flexible Pavement Moduli

2005 ◽  
Vol 1905 (1) ◽  
pp. 117-127 ◽  
Author(s):  
T. F. Fwa ◽  
Thakur Swapna Rani
Keyword(s):  
Closed Form ◽  
Flexible Pavements ◽  
Flexible Pavement ◽  
Pavement Performance ◽  
Program Performance ◽  
Generation Algorithm ◽  
User Input ◽  
Pavement Structures ◽  
Performance Project

The seed moduli chosen for backcalculation analysis of multilayer flexible pavements can have significant impacts on the performance of backcalculation software and, sometimes, the final solutions of the backcalculated moduli. Practically all backcalculation programs provide internally generated seed moduli for backcalculation analysis. However, as the internally generated seed moduli do not always produce satisfactory results, the use of user-input seed moduli is generally encouraged. With the aim of providing useful guidance in the choice of seed moduli, a seed modulus generation algorithm, 2L-BACK, for multilayer flexible pavements based on a closed-form modulus backcalculation solution for two-layer flexible pavement structures was developed. The proposed algorithm does not require any subjective judgment by the user. An evaluation analysis of the effectiveness of the proposed procedure is presented by the use of two types of backcalculation software, MICHBACK and EVERCALC, and is based on measured and computed data for flexible pavement segments from the Long-Term Pavement Performance project. A comparison was made of the backcalculation program performance and the computed moduli of solutions obtained from internally generated seed moduli and those obtained from seed moduli generated by the proposed algorithm. It was found that the proposed seed modulus generation algorithm led to enhanced program performance of MICHBACK with respect to convergence characteristics and the accuracies of the backcalculated solutions. In comparison, the corresponding improvements for the case of EVERCALC were less. The proposed seed modulus generation algorithm does not suffer from the location and pavement type transferability constraints of most regression-based seed modulus generation methods. The results of the study suggest that the algorithm can be effectively incorporated into backcalculation software for multilayer flexible pavements.

A mechanistic evaluation of modified asphalt paving mixtures

1994 ◽  
Vol 21 (6) ◽  
pp. 954-965 ◽  
Author(s):  
N. Ali ◽  
Shaher Zahran ◽  
Jim Trogdon ◽  
Art Bergan
Keyword(s):  
Prediction Model ◽  
Pavement Performance ◽  
Pavement Distress ◽  
Modified Asphalt ◽  
Significant Difference ◽  
Actual Field ◽  
Asphalt Paving ◽  
Polymer Modified Asphalt ◽  
Pavement Performance Prediction

The main purpose of this study was to facilitate decisions concerning the effectiveness of modifiers in mitigating pavement distress and improving long-term overall pavement performance in actual field conditions, by utilizing short-term laboratory results and a mathematical prediction model. The modifiers investigated were carbon black, neoprene latex, and polymer modified asphalt (STYRELF). The statistical general linear model (GLM) and the Fisher least significant difference (LSD) were used for the analysis of data. The results of the study indicate that the effect of the modifier on the paving mixture properties was insignificant at low temperatures (down to −17 °C), but significant at high temperatures (up to 60 °C) where the synergistic effect of the modifier on the paving mixture was pronounced. The VESYS IIIA pavement performance prediction model was utilized to assess the effects, if any, of the modifier on the pavement's overall performance. All the modifiers improve, to some degree, the overall pavement performance. Key words: modifiers, asphalt, paving mixtures, pavements, polymer asphalt.

Use of Long Term Pavement Performance-Seasonal Monitoring Program Data to Develop and Validate a Generalized Regression Model to Predict the In-Situ Resilient Modulus of Subgrade Soils for Pavement Design and Evaluation

2020 ◽  
Vol 2674 (5) ◽  
pp. 673-684
Author(s):  
Mohamed Elshaer ◽  
Christopher DeCarlo ◽  
Wade Lein ◽  
Harshdutta Pandya ◽  
Ayman Ali ◽  
...  
Keyword(s):  
Prediction Model ◽  
Resilient Modulus ◽  
Monitoring Program ◽  
Pavement Design ◽  
Pavement Performance ◽  
Regression Approach ◽  
Seasonal Monitoring ◽  
Generalized Regression

Resilient modulus (Mr) is a critical input for pavement design as it is the main property used to evaluate the contribution of subgrade to the overall pavement structure. Considering this, practitioners need simple and accurate ways to determine the Mr of in-situ subgrade without the need for expensive and time-consuming testing. The objective of this study is to develop a generalized regression prediction model for in-situ Mr of subgrades, compare it with established prediction models, and assess the model’s predictions on pavement performance using the Mechanistic-Empirical Pavement Design Guide (Pavement ME). The prediction model was built using field data from 30 pavement sections studied in the Long Term Pavement Performance (LTPP) Seasonal Monitoring Program where backcalculated modulus from falling weight deflectometer testing, in-situ moisture contents, and subgrade material properties were considered in the model. Based on the results, it was found that liquid limit, plasticity index, WPI (the product of percent passing #200 and plasticity index), percent coarse sand, percent fine sand, percent silt, percent clay, moisture content, and their respective interactions were significant predictors of in-situ Mr values. The findings showed that the generalized regression approach was able to predict Mr more accurately than predictions from the Witczak model. To assess the application of the predictive model on pavement performance, three LTPP sections located in New York, South Dakota, and Texas were analyzed to predict the rutting performance based on Mr values obtained from the developed generalized prediction model and those obtained from the current Pavement ME model and then compared with rut depths measured in the field. The findings showed that, for coarse-grained subgrades that have a low degree of plasticity, the generalized regression model predicted rutting performance similar to the embedded Pavement ME model. For fine-grained subgrades, the developed model tends to predict lower rut depths which were closer to the field measured rut depths. Overall, the generalized regression approach was successfully applied to create a simple, practical, cost-effective and accurate Mr prediction model that can be used to estimate the stiffness of subgrades when designing and evaluating pavements.

scholarly journals Development of an automated high-temperature valveless injection system for online gas chromatography

2014 ◽  
Vol 7 (12) ◽  
pp. 4431-4444 ◽  
Author(s):  
N. M. Kreisberg ◽  
D. R. Worton ◽  
Y. Zhao ◽  
G. Isaacman ◽  
A. H. Goldstein ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Ambient Pressure ◽  
Field Performance ◽  
Sample Introduction ◽  
Injection System ◽  
Continuous Sampling ◽  
Atmospheric Sampling ◽  
Performance Results

Abstract. A reliable method of sample introduction is presented for online gas chromatography with a special application to in situ field portable atmospheric sampling instruments. A traditional multi-port valve is replaced with a valveless sample introduction interface that offers the advantage of long-term reliability and stable sample transfer efficiency. An engineering design model is presented and tested that allows customizing this pressure-switching-based device for other applications. Flow model accuracy is within measurement accuracy (1%) when parameters are tuned for an ambient-pressure detector and 15% accurate when applied to a vacuum-based detector. Laboratory comparisons made between the two methods of sample introduction using a thermal desorption aerosol gas chromatograph (TAG) show that the new interface has approximately 3 times greater reproducibility maintained over the equivalent of a week of continuous sampling. Field performance results for two versions of the valveless interface used in the in situ instrument demonstrate typically less than 2% week−1 response trending and a zero failure rate during field deployments ranging up to 4 weeks of continuous sampling. Extension of the valveless interface to dual collection cells is presented with less than 3% cell-to-cell carryover.

“Off-the-Wall” Pavement Distress Variability Study

1998 ◽  
Vol 1643 (1) ◽  
pp. 62-70 ◽  
Author(s):  
Jerome F. Daleiden ◽  
Amy L. Simpson
Keyword(s):  
Data Collection ◽  
Pavement Performance ◽  
Human Errors ◽  
Projection System ◽  
Pavement Distress ◽  
Sophisticated Equipment ◽  
Surface Distress ◽  
The Impact ◽  
Variability Study

Variability of pavement surface distress data collection has always been an area of significant concern. When conducting evaluations of distress data manually (with raters observing pavements in question, interpreting what they see, and recording on paper) the process is subject to human errors. To minimize the impact of such human errors on these important pavement performance data, sophisticated equipment has been developed to eliminate as much of the human intervention as possible. Such technology is not without its own limitations of precision and bias. With both methodologies being used for the collection of surface distress data for the long-term pavement performance (LTPP) program, questions regarding precision and bias have been identified. In attempting to define the variability of the data for incorporation in stochastic analyses, it has become apparent how diverse and complex these distress data truly are. To adequately quantify the precision and bias, a detailed experiment was designed to evaluate the errors inherent in the different distress data collection methodologies. The facet of the experiment reported targets the variability of human distress surveyors and the biases associated with conducting surveys from film, using a slightly different projection system. Specifically, a collection of surveyors was assembled to establish the variability associated with experienced raters versus novice raters, engineers versus engineering technicians, and teams versus individuals.

Determining the Age and Smoothness of Asphalt and Concrete Pavements at the Time of First Rehabilitation using Long-Term Pavement Performance Program Data

2018 ◽  
Vol 2672 (40) ◽  
pp. 176-185 ◽  
Author(s):  
Mary Robbins ◽  
Nam Tran ◽  
Audrey Copeland
Keyword(s):  
Life Cycle Cost ◽  
Evaluation Process ◽  
Concrete Pavement ◽  
Asphalt Pavements ◽  
Pavement Performance ◽  
Concrete Pavements ◽  
Pavement Roughness ◽  
And Performance ◽  
Program Data

Initial performance period is an important input in life-cycle cost analysis (LCCA). An objective of this study was thus to determine actual initial performance periods, as the pavement age at first rehabilitation, for asphalt and concrete pavements using Long-Term Pavement Performance (LTPP) program data. In addition, most agencies use International Roughness Index (IRI), a measure of pavement roughness applicable to both asphalt and concrete pavements, in their decision-making and performance-evaluation process. A secondary objective was, therefore, to determine the pavement roughness condition at the time of first rehabilitation using the same dataset. Based on surveys of highway agencies, initial performance periods frequently used in LCCA for asphalt pavements are between 10 and 15 years, while the average asphalt pavement age at time of first rehabilitation in the LTPP program was found to be approximately 18 years. For concrete pavements, most initial performance periods used in LCCA are between 20 and 25 years, whereas the average concrete pavement age at the time of first rehabilitation in the LTPP program is about 24 years. This suggests initial performance period values used for LCCA do not adequately represent the actual age of asphalt pavements at the time of first rehabilitation, while they are generally representative of actual concrete pavement age at the time of first rehabilitation. Also, it was found that asphalt pavements are typically rehabilitated when they are in good or fair condition according to Federal Highway Administration (FHWA) IRI criteria whereas concrete pavements are typically not rehabilitated until the pavement is in fair or poor condition.

Performance of Flexible Pavement Rehabilitation Treatments in the Long-Term Pavement Performance SPS-5 Experiment

2003 ◽  
Vol 1823 (1) ◽  
pp. 93-101 ◽  
Author(s):  
Kathleen T. Hall ◽  
Carlos E. Correa ◽  
Amy L. Simpson
Keyword(s):  
Asphalt Pavement ◽  
Fatigue Cracking ◽  
Flexible Pavement ◽  
Asphalt Pavements ◽  
Pavement Performance ◽  
Recycled Asphalt ◽  
Pavement Rehabilitation ◽  
Pretreatment Condition ◽  
Asphalt Overlay

The results of a study conducted to assess the relative performance of different flexible pavement rehabilitation treatments, including the influence of pretreatment condition and other factors, are presented. The data used in the study were drawn from the Long-Term Pavement Performance Studies' Specific Pavement Study (SPS) SPS-5 and General Pavement Study (GPS) GPS-6B experiments. The rehabilitation treatments used in the SPS-5 experiment are 2- and 5-in. overlays with virgin or recycled asphalt concrete mixes with or without preoverlay milling. Overlay thickness and preoverlay roughness levels were the two factors that most influenced the performance of the asphalt overlays of asphalt pavements in the SPS-5 experiment with respect to roughness, rutting, and fatigue cracking. Over the long term, the 5-in. overlays outperformed the 2-in. overlays with respect to roughness, rutting, and fatigue cracking. Overlay mix type (virgin versus recycled) and preoverlay preparation (with or without milling) had slight and inconsistent effects. The average initial postoverlay international roughness index of an asphalt overlay of an asphalt pavement was found to be 0.98 m/km. The data show a slight but statistically significant tendency for asphalt pavements overlaid when they were rougher to have more initial roughness after overlay than asphalt pavements overlaid when they were smoother. The data show that, on average, about 6 mm of rutting develops in the first year or so after placement of an asphalt overlay of an asphalt pavement. This is presumably due to compaction of the mix by traffic and appears to be independent of the overlay thickness, mix type, preoverlay preparation, and preoverlay rutting level.

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