Integrating the Dynamic Modulus of Asphalt Mixes in the 1993 AASHTO Design Method

2017 ◽  
Vol 2640 (1) ◽  
pp. 29-40 ◽  
Author(s):  
Yara S. Hamdar ◽  
Ghassan R. Chehab
Keyword(s):  
Dynamic Modulus ◽  
Resilient Modulus ◽  
Design Method ◽  
Asphalt Mixture ◽  
Base Layer ◽  
Asphalt Mixes ◽  
Design Guide ◽  
Abstract Measure ◽  
Pavement Structures ◽  
Structural Coefficient

The AASHTO Guide for Design of Pavement Structures 1993 (1993 Design Guide) remains the most widely used pavement design manual by highway agencies and design consultants around the world. As defined in the 1993 Design Guide, the structural coefficient of a pavement layer ( ai) is an abstract measure of the relative ability of a unit thickness of a given material to function as a structural component of the pavement. Nevertheless, the assumed ai values of the asphalt layers and a proposed relationship between ai and the resilient modulus do not account for the mechanical and physical properties of asphalt materials, traffic volume and speed, layer thicknesses (thin versus thick pavements), climate, and unbound layer properties. The purpose of this research was to enhance the design methodology incorporated in the 1993 Design Guide by integrating asphalt mixture properties in the design process. The objective was to devise a relationship between the structural coefficient ( ai) of the asphalt layer and the effective dynamic modulus (|E*|eff.) of the corresponding asphalt mix to yield a more realistic estimate of the structural capacity of the asphalt layer. The paper illustrates the development of a multilinear relationship between ai, (|E*|eff.), and the resilient modulus of the aggregate base layer. Pavement structural designs for various asphalt mixes and design inputs using the developed ai–(|E*|eff.) relationship yielded asphalt layer thicknesses that were generally smaller than those obtained using the typical ai value of 0.44 for the asphalt layer and closer to thicknesses obtained with the AASHTO mechanistic–empirical design method using the Pavement ME software.

scholarly journals Performance Evaluation of Hot Mix Asphalt with Different Proportions of RAP Content

2018 ◽  
Vol 34 ◽  
pp. 01026
Author(s):  
Ahmad Kamil Arshad ◽  
Haryati Awang ◽  
Ekarizan Shaffie ◽  
Wardati Hashim ◽  
Zanariah Abd Rahman
Keyword(s):  
Hot Mix Asphalt ◽  
Resilient Modulus ◽  
Design Method ◽  
Asphalt Pavement ◽  
Cost Savings ◽  
Volumetric Analysis ◽  
Public Works ◽  
Asphalt Binders ◽  
Moisture Susceptibility ◽  
Asphalt Mixes

Reclaimed Asphalt Pavement (RAP) is old asphalt pavement that has been removed from a road by milling or full depth removal. The use of RAP in hot mix asphalt (HMA) eliminates the need to dispose old asphalt pavements and conserves asphalt binders and aggregates, resulting in significant cost savings and benefits to society. This paper presents a study on HMA with different RAP proportions carried out to evaluate the volumetric properties and performance of asphalt mixes containing different proportions of RAP. Marshall Mix Design Method was used to produce control mix (0% RAP) and asphalt mixes containing 15% RAP, 25% RAP and 35% RAP in accordance with Specifications for Road Works of Public Works Department, Malaysia for AC14 dense graded asphalt gradation. Volumetric analysis was performed to ensure that the result is compliance with specification requirements. The resilient modulus test was performed to measure the stiffness of the mixes while the Modified Lottman test was conducted to evaluate the moisture susceptibility of these mixes. The Hamburg wheel tracking test was used to evaluate the rutting performance of these mixes. The results obtained showed that there were no substantial difference in Marshall Properties, moisture susceptibility, resilient modulus and rutting resistance between asphalt mixes with RAP and the control mix. The test results indicated that recycled mixes performed as good as the performance of conventional HMA in terms of moisture susceptibility and resilient modulus. It is recommended that further research be carried out for asphalt mixes containing more than 35% RAP material.

A Method for Temperature Correction of HMA Dynamic Modulus

2012 ◽  
Vol 178-181 ◽  
pp. 1615-1618 ◽  
Author(s):  
Ya Li Ye ◽  
Chuan Yi Zhuang ◽  
Ren Feng Zhang
Keyword(s):  
Dynamic Modulus ◽  
Asphalt Mixture ◽  
Temperature Correction ◽  
Reference Temperature ◽  
Wheel Load ◽  
Pavement Deterioration ◽  
Design Guide ◽  
Falling Weight ◽  
Asphalt Concrete Pavement

HMA dynamic modulus is one of key inputs to the Mechanistic-Empirical Pavement Design Guide. In order to analyze and evaluate bearing capacity of asphalt concrete pavement and to determinate the rules of pavement deterioration of modulus of asphalt layer under repeated wheel load and ambient, temperature correction for HMA is applied to the modulus so as to compare them with the same temperature. In order to get temperature correction coefficients for HMS moduli, a method of temperature correction for HMA moduli was put forward. In this method, the specimen of asphalt mixture or HMA cores from in-situ pavements were tested by Superpave Simple Performance Tester(SPT), or falling weight deflection(FWD) was tested on the site of in-situ pavements. The correlation between HMA dynamic modulus and temperature was regressed, and then dynamic modulus regression model was put forward. Results show that exponential function was fitted to the data to determine and adjust the modulus to a reference temperature, the recommendation regression equation can reflect the features of asphalt mixture at the reference temperature.

scholarly journals Measurement of Dynamic Modulus and Master Curve Modeling of Hot Mix Asphalt from Senegal (West Africa)

2015 ◽  
Vol 2 (1) ◽  
pp. 124 ◽  
Author(s):  
Mouhamed Lamine Chérif Aidara ◽  
Makhaly Ba ◽  
Alan Carter
Keyword(s):  
Dynamic Modulus ◽  
Master Curve ◽  
Hot Mix Asphalt ◽  
Complex Modulus ◽  
Test Results ◽  
Asphalt Mixes ◽  
Design Guide ◽  
Asphalt Mix ◽  
Sigmoidal Model ◽  
Curve Modeling

The main purpose of this paper is to model the master curve of dynamic modulus |E*| for Hot Mix Asphalt mix designed with aggregate from Senegal named basalt of Diack and quartzite of Bakel. The prediction model used is the Witczak model, used in the Mechanistic-Empirical Pavement Design Guide. A study has been conducted in the Laboratory of Pavements and Bituminous Materials. Six different HMA (BBSG 0/14 mm) were subjected to complex modulus test by tension-compression according to the European or Canadian procedure using the same range of temperatures and frequencies. For each mixture studied the uniqueness of modulus curves in the Cole-Cole or in Black diagrams have shown that the asphalt mixes are thermorheologically simple materials and the Canadian test process is suitable for determining the HMA complex modulus mix designed with the aggregates from Senegal. This implies their tender with the principle of time-temperature equivalence. The test results were used to model the master curves of HMA studied. A correlation with the results of dynamic modulus measured have shown an accuracy of R2 = 0,99 and p = 0,00 in STATISTICA software, which allows to conclude that the sigmoidal model has good modeling of the dynamic modulus.

scholarly journals Effect Of Resilient Modulus on Permanent Deformations Using VESYS 5W Program

2022 ◽  
Vol 961 (1) ◽  
pp. 012007
Author(s):  
Hasan H Joni ◽  
Yassir K Hadi
Keyword(s):  
Surface Layer ◽  
High Temperatures ◽  
Resilient Modulus ◽  
Base Layer ◽  
Asphalt Mixes ◽  
Potential Value ◽  
Traffic Loads ◽  
Pavement Layers

Abstract Due to high temperatures and increased traffic loads, most of Iraq’s streets suffer from permanent distortion problems, especially in streets where there are checkpoints, therefore, there are needs for reports and researches specialized in improving the pavement layers and increasing their resistance to temperatures and high traffic loads to reduce the rut depth. In this research, the VESYS 5W program was used to find a potential value for rut depth, where ordinary asphalt mixes and improved asphalt mixes were used using SBS polymer at 4% by weight of asphalt were it is evaluated according to different properties of these mixture and the resilient modulus one of these properties for it is importance. The results showed that when the value of the resilient modulus increases, the rut depth decreases, as the rut depth was reduced by 42.5% for the surface layer and 73% for the base layer

Evaluation Of Volumetric Properties And Resilient Modulus Performance Of Nanopolyacrylate Polymer Modified Binder (NPMB) Asphalt Mixes

2015 ◽  
Vol 73 (4) ◽  
Author(s):  
Ekarizan Shaffie ◽  
Juraidah Ahmad ◽  
Ahmad Kamil Arshad ◽  
Dzraini Kamarun
Keyword(s):  
Resilient Modulus ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Volumetric Properties ◽  
Modified Bitumen ◽  
Asphalt Mixes ◽  
Different Types ◽  
Potential Benefits ◽  
Modified Binder ◽  
Polymer Modified Bitumen

This paper presents the potential benefits of nanopolyacrylate (NPA) for the asphalt mixtures used on pavement. This research evaluates the resilient modulus performance of dense graded Superpave-designed HMA mix. Two different types of dense graded Superpave HMA mix were developed consists of unmodified bitumen mix (UMB) and nanopolyacrylate modified bitumen mix (NPMB). Nanopolyacrylate polymer modified bitumen was prepared from addition of 6 percent of NPA polymer into asphalt bitumen. Resilient modulus results from Resilient Modulus test were determined to evaluate the performance of these mixtures. Results showed that all the mixes passed the Superpave volumetric properties criteria which indicated that these mixtures were good with respect to durability and flexibility. The Resilient modulus result of NPMB demonstrates better resistance to rutting than those prepared using UMB mix. It was estimated that the average resilient modulus values for both UMB and NPMB mixtures are decreased by 80 percent when the test temperature increased from 25ºC to 40ºC.   In conclusion, the addition of NPA to the binder has certainly improved the bitumen properties significantly and hence increase the resistant to rutting of the asphalt mixture.

Study on Flexible Base Asphalt Pavement Design System Based on the Dynamic Modulus

2013 ◽  
Vol 788 ◽  
pp. 619-622
Author(s):  
Li Yin
Keyword(s):  
Mechanical Properties ◽  
Dynamic Modulus ◽  
Design Method ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Pavement Design ◽  
Pavement Performance ◽  
Design System ◽  
Determination Method ◽  
Flexible Base

Pavement design adopts the static index pavement design method; it has significant limitations for flexible asphalt pavement. This paper proposes asphalt mixture dynamic modulus determination method on the basis of existing research results at home and abroad. Dynamic modulus effect is studied on the mechanical properties of flexible base asphalt pavement, and the flexible base asphalt pavement performance is preestimated by the use of the dynamic modulus indicators in the paper.

Evaluation of the Response Analysis Approach Used in the Mechanistic-Empirical Pavement Design Guide

2020 ◽  
pp. 036119812097401
Author(s):  
Guozhi Fu ◽  
Yanqing Zhao ◽  
Wanqiu Liu ◽  
Changjun Zhou
Keyword(s):  
Phase Angle ◽  
Dynamic Modulus ◽  
Master Curve ◽  
Compressive Strain ◽  
Pavement Design ◽  
Base Layer ◽  
Response Analysis ◽  
Rate Dependency ◽  
Rate Dependent ◽  
Design Guide

Asphalt concrete (AC) is a typical viscoelastic material exhibiting rate-dependent behavior. The rate-dependency of AC should be properly taken into consideration in pavement response analysis to accurately evaluate pavement performance and life. In the Mechanistic-Empirical Pavement Design Guide (MEPDG), the dynamic modulus master curve is used to account for the rate-dependency of the dynamic modulus of AC. However, the rate-dependent phase angle is ignored and a constant phase angle of 0 is assumed. The partial characterization of rate-dependent properties of AC in the MEPDG may lead to inaccurate results. This study compares the pavement responses computed using the MEPDG approach and the layered viscoelastic theory (LVET) which utilizes the complex modulus master curve to fully characterize the rate-dependent properties of AC. Typical three-layer pavement structures were analyzed at three temperatures (−10°C, 20°C and 50°C) and four speeds (10, 40, 80 and 120 km/h). The results show that the horizontal tensile stresses at the bottom of cement-treated base layer obtained from the two approaches are almost the same, and for other responses analyzed, the results obtained from the MEPDG approach are larger than those from the LVET approach, especially for the responses in the AC layer. The normalized difference of the vertical compressive strain at the mid-depth of the AC layer between the two approaches can be up to 100% and that for the horizontal tensile strain at the bottom of the AC layer can be more than 50%.

Evaluation of a Predicted Dynamic Modulus for Florida Mixtures

2005 ◽  
Vol 1929 (1) ◽  
pp. 200-207 ◽  
Author(s):  
Bjorn Birgisson ◽  
Gregory Sholar ◽  
Reynaldo Roque
Keyword(s):  
Dynamic Modulus ◽  
State Agencies ◽  
Department Of Transportation ◽  
University Of Florida ◽  
Florida Department ◽  
Design Guide ◽  
Level 3 ◽  
Pavement Structures ◽  
The University ◽  
Level 2

The new 2002 AASHTO guide for the design of pavement structures is based on mechanistic principles and requires the dynamic modulus as input to compute stress, strain, and rutting and cracking damage in flexible pavements. The 2002 AASHTO guide has three different levels of analysis; the level used depends on the importance of the pavement structure in question. Dynamic modulus testing is required for Level 1 pavement analysis, whereas no laboratory test data are required for Level 2 and Level 3 pavement analysis. Instead, a predictive dynamic modulus equation is used to generate input values. It is of significant importance to state agencies to understand how well the dynamic modulus for locally available materials compares with the predicted dynamic modulus. This paper presents the results of a study by the Florida Department of Transportation and the University of Florida that focused on the evaluation of the dynamic modulus predictive equation used in the new AASHTO 2002 guide for mixtures typical to Florida. The resulting research program consisted of dynamic modulus testing of 28 mixtures common to Florida. Results showed that on average the predictive modulus equation used in the new AASHTO 2002 flexible pavement design guide appeared to work well for Florida mixtures when used with a multiplier to account for the uniqueness of local mixtures. Results of the study also identified optimal viscosity–temperature relationships that result in the closest correspondence between measured and predicted dynamic modulus values.

Evaluation of the Effect of Lime Modification on the Dynamic Modulus Stiffness of Hot-Mix Asphalt

2005 ◽  
Vol 1929 (1) ◽  
pp. 10-19 ◽  
Author(s):  
Javed Bari ◽  
Matthew W. Witczak
Keyword(s):  
Dynamic Modulus ◽  
Hot Mix Asphalt ◽  
High Volume ◽  
Hydrated Lime ◽  
Standard Test ◽  
Pavement Design ◽  
State University ◽  
Arizona State University ◽  
Design Guide ◽  
Pavement Structures

Hydrated lime is often used as a mineral filler or antistripping additive in hot-mix asphalt (HMA). Many agencies across North America require the use of lime in all HMA mixtures being placed on high-volume roadways. Despite this wide use of lime, its effects on the HMA mixture dynamic modulus (E*) stiffness have rarely been evaluated. The new mechanistic–empirical (M-E) pavement design guide, Guide for Mechanistic–Empirical Design of New and Rehabilitated Pavement Structures, developed under NCHRP Project 1–37A uses E* as the primary material property of asphalt mixtures for the HMA characterization. A comprehensive study was completed at Arizona State University to assess the effect of lime addition on the E* stiffness of HMA mixtures. The study demonstrated that the standard test and design methodologies of the new M-E pavement design guide could be used effectively for lime-modified HMA mixes. With these methodologies, hydrated lime was found to increase the E* of HMA mixtures by 17% to 65% across the range of mixtures, lime contents, and temperature, with an overall average of 25% increase found from 17 mixture–lime percentage combinations across six different HMA mixes. This paper also outlines a provisional protocol for evaluating the E* master curve for lime-modified HMA mixtures using any of the three hierarchical levels found in the new NCHRP Project 1–37A pavement design guide.

Short-Loading-Time Stiffness from Creep, Resilient Modulus, and Strength Tests Using Superpave Indirect Tension Test

1998 ◽  
Vol 1630 (1) ◽  
pp. 10-20 ◽  
Author(s):  
Reynaldo Roque ◽  
William G. Buttlar ◽  
Byron E. Ruth ◽  
Stephen W. Dickison
Keyword(s):  
Dynamic Modulus ◽  
Resilient Modulus ◽  
Asphalt Mixture ◽  
Data Interpretation ◽  
Accurate Method ◽  
Load Level ◽  
Asphalt Mixtures ◽  
Strength Tests ◽  
Indirect Tension ◽  
Indirect Tension Test

The Superpave indirect tension (IDT) system was modified to determine the short-loading-time stiffness of asphalt mixtures from resilient modulus, creep, and strength tests. The idea was not only to provide a more accurate method to determine the resilient modulus, but also to determine whether reasonable measures of short-loading-time stiffness could be obtained from tests that provide other properties and thereby minimize the amount of testing needed to characterize asphalt mixtures. It was found that even when evaluated at very short loading times, the stiffnesses determined from the different tests were significantly different. Detailed evaluation indicated that the differences can be explained by the differences in loading rates between the tests. In general, stiffnesses from the different tests all appeared to be reasonable and followed the same trend. However, since the rheological behavior of asphalts and mixtures varies, stiffnesses from different tests were not directly related. Therefore, although the interpretation methods developed in this study for creep and strength tests appear to provide a reasonable alternative to the resilient or dynamic modulus, the short-loading-time stiffnesses determined from these tests are not directly comparable with the resilient or dynamic modulus or with each other. The work illustrates the sensitivity of stiffness to relatively small changes in loading rate and other variables, which emphasizes the need to precisely define load pattern, load level, and data interpretation methods to determine asphalt mixture stiffness at short loading times.

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