Comparison of flow number, dynamic modulus, and repeated load tests for evaluation of HMA permanent deformation

2013 ◽  
Vol 44 ◽  
pp. 391-398 ◽  
Author(s):  
Jun Zhang ◽  
Allex E. Alvarez ◽  
Sang Ick Lee ◽  
Angela Torres ◽  
Lubinda F. Walubita
Keyword(s):  
Dynamic Modulus ◽  
Permanent Deformation ◽  
Flow Number ◽  
Load Tests ◽  
Repeated Load

Performance of Virginia’s Early Foamed Warm Mix Asphalt Mixtures

2018 ◽  
Vol 2672 (28) ◽  
pp. 178-189 ◽  
Author(s):  
Stacey D. Diefenderfer
Keyword(s):  
Dynamic Modulus ◽  
Permanent Deformation ◽  
Warm Mix Asphalt ◽  
Department Of Transportation ◽  
High Dynamic ◽  
Repeated Load ◽  
And Performance ◽  
Virginia Department ◽  
Performance Grading ◽  
Air Void

The Virginia Department of Transportation began allowing the use of warm mix asphalt (WMA) in 2008. Although several WMA technologies were investigated prior to implementation, foamed WMA was not. This study evaluated the properties and performance of foamed WMA placed during the initial implementation of the technology to determine whether the technology had performed as expected. Six mixtures produced using plant foaming technologies and placed between 2008 and 2010 were identified and subjected to field coring and laboratory testing. Coring was performed in 2014, resulting in pavement ages from 4 to 6 years. Three comparable hot mix asphalt (HMA) mixtures were cored at 5 years for comparison. Cores were evaluated for air-void contents and permeability and were subjected to dynamic modulus, repeated load permanent deformation, and overlay testing. In addition, binder was extracted and recovered for performance grading. Similar properties were found for the WMA and HMA mixtures. One WMA mixture had high dynamic modulus and binder stiffness, but overlay testing did not indicate any tendency for premature cracking. All binders had aged between two and three performance grades above that specified at construction. WMA binders and one HMA binder aged two grades higher, and the remaining two HMA binders aged three grades higher, indicating a likely influence on aging of the reduced temperatures at which the early foamed mixtures were typically produced. Overall results indicated that foamed WMA and HMA mixtures should be expected to perform similarly.

Three-Stage Permanent Deformation Behavior of Subgrade Soils

2011 ◽  
Vol 374-377 ◽  
pp. 1942-1946
Author(s):  
Rui Fang ◽  
Hui Gao ◽  
Xiang Qin Bian
Keyword(s):  
Mechanistic Model ◽  
Permanent Deformation ◽  
Silty Clay ◽  
Test Results ◽  
Creep Equation ◽  
New Model ◽  
Subgrade Soils ◽  
Load Tests ◽  
Three Stages ◽  
Repeated Load

The development of the permanent deformation of subgrade soils under repeated load tests may consists of three stages, namely the primary, secondary and tertiary stages, but the existing models can not describe this behavior very well, so a new model is required to be developed. Based on the creep equation of the soil under static load, a mechanistic model is developed to describe the development of the permanent deformation of the soil under repeated load tests. Triaxial repeated load tests are conducted for silty soils and results show that, under some conditions, the development of the permanent deformation of silty clay consists of three stages and the number of load repetitions corresponding to the initiation of the tertiary stage is 330,0000. The new model is used to fit the test results and the comparison of test results and fitting results prove that this model can describe all three stages of permanent deformation.

scholarly journals Rutting mechanisms and advanced laboratory testing of asphalt mixtures resistance against permanent deformation

2011 ◽  
Vol 9 (3) ◽  
pp. 407-417 ◽  
Author(s):  
Miomir Miljkovic ◽  
Martin Radenberg
Keyword(s):  
Traffic Safety ◽  
Triaxial Compression ◽  
Permanent Deformation ◽  
Asphalt Pavements ◽  
Flow Number ◽  
Potential Link ◽  
Deformation Test ◽  
Test Flow ◽  
Repeated Load

Permanent deformation in asphalt layers which manifestation on pavement surface is named rutting represents one of the most significant distresses of asphalt pavements. Depending on the level, it can be a huge inconvenience for traffic safety, driving comfort, and overall pavement life-cycle. Rutting may be classified into three basic types: one-dimensional or vertical compaction, lateral flow or plastic movement, and mechanical deformation. As an addition to Superpave? mixture volumetric design three, so called, simple performance tests (SPT) were recommended. Each of these tests in conduced in uniaxial or triaxial compression of cylindrical specimens. They cover the determination of dynamic modulus, repeated load permanent deformation test (flow number), and static load permanent deformation test (flow time). These tests provide relatively good insight in on-site mixture performance. An application of these tests provides a potential link between mixture design and structural analysis that was an underlying goal of substantial amount of earlier flexible pavement researches.

Characterization of Permanent Deformation of Asphalt Mixtures with Minimum Strain Rate, LVECD Program, and Triaxial Stress Sweep Test

2017 ◽  
Vol 2631 (1) ◽  
pp. 96-104 ◽  
Author(s):  
Dahae Kim ◽  
Y. Richard Kim
Keyword(s):  
Permanent Deformation ◽  
Single Layer ◽  
Asphalt Mixtures ◽  
Triaxial Stress ◽  
Structural Level ◽  
Flow Number ◽  
Specific Test ◽  
Rutting Resistance ◽  
Testing Effort ◽  
Repeated Load

The rutting resistance of asphalt concrete is typically assessed by using flow number tests in the lab in accordance with AASHTO TP 79. However, the flow number represents the rutting resistance of the material with regard to ranking for only a specific test condition. A significant amount of testing effort is needed to evaluate rutting resistance by using the flow number test under various loading conditions and temperatures. Therefore, researchers have developed alternative test methods to reduce the testing effort. For example, the incremental repeated-load permanent deformation test and the triaxial stress sweep (TSS) test are two promising protocols that can predict the permanent deformation of asphalt mixtures efficiently and accurately. This study compares the minimum strain rates (MSRs) obtained from incremental repeated-load permanent deformation and TSS tests to examine the ability of the TSS test to analyze the MSRs of asphalt mixtures. In addition, the viscoplastic shift model calibrated from the TSS test that is implemented in the layered viscoelastic pavement analysis for critical distresses (LVECD) program was used to predict the rut depths of 16 pavement sections from four sources. The MSRs and rut depths predicted from the LVECD program were compared with actual measured rut depths. The results of this study indicated that the MSR results could only be used to rank the rutting susceptibility of single-layer asphalt pavements. For a multilayered pavement system, structural level analysis is necessary to predict the accurate rutting performance and rut depths of the test sections.

A preliminary study of the mechanical properties of asphalt mixture containing bottom ash

2008 ◽  
Vol 35 (10) ◽  
pp. 1114-1119 ◽  
Author(s):  
Shu Wei Goh ◽  
Zhanping You
Keyword(s):  
Mechanical Properties ◽  
Dynamic Modulus ◽  
Permanent Deformation ◽  
Bottom Ash ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Test Results ◽  
Flow Number ◽  
Preliminary Study ◽  
Primary Focus

This paper shows a preliminary study of asphalt mixtures containing bottom ash with a primary focus on the permanent deformation. The objectives of this study are (i) perform literature reviews on the mechanical properties of asphalt mixtures containing bottom ash; (ii) evaluate the effects of using bottom ash as the mineral filler for the asphalt mixture through the flow number and dynamic modulus tests; and (iii) use the test results to evaluate the pavement permanent deformation using the Mechanistic–empirical pavement design guide (MEPDG) analysis. It was found that the asphalt mixture using bottom ash uses higher asphalt content due to the higher absorption. The replacement with bottom ash in the asphalt mixture generates a lower dynamic modulus as compared to the control mixtures. Additionally, results from MEPDG analysis show mixtures with bottom ash have higher rutting potential.

Preliminary Field Validation of Simple Performance Tests for Permanent Deformation: Case Study

2003 ◽  
Vol 1832 (1) ◽  
pp. 209-216 ◽  
Author(s):  
Fujie Zhou ◽  
Tom Scullion
Keyword(s):  
Dynamic Modulus ◽  
Permanent Deformation ◽  
Mixture Design ◽  
Asphalt Mixtures ◽  
Load Test ◽  
Performance Tests ◽  
Field Validation ◽  
Dynamic Modulus Test ◽  
Repeated Load

Simple performance tests (SPTs) to be used with the Superpave® volumetric mixture design procedure were recently recommended by NCHRP Project 9-19 (Simple Performance Test for Superpave Mix Design). Field validation of the SPTs is critical to their final acceptance and implementation in Superpave mixture design practice. Special Pavement Studies-1 (SPS-1) prematurely rutted sections on US-281 in Texas were used to validate the SPTs for permanent deformation, including the dynamic modulus test and repeated-load test and associated rutting indicators E*/sin δ and flow number ( F n), respectively. The results of this case study clearly show that both the dynamic modulus test and E*/sin δ and the repeated-load test and F n can effectively distinguish the good mixtures from the bad. Compared with E*/sin δ, F n can better differentiate the performance of asphalt mixtures. These results preliminarily validated both SPTs for permanent deformation. In addition, the location of the tertiary point in the plot of permanent strain versus number of load repetitions is clarified; a simple linear model needs to be added in order to determine the F n. Furthermore, the possibility of using the number of load repetitions ( Nps) corresponding to the initial point of the secondary stage to characterize the rutting resistance of asphalt mixtures is discussed. The new indicator proposed is supported by the limited data presented in this paper and can be easily determined and can reduce test duration significantly.

Permanent Deformation of Steel under Slowly Repeated Load

1954 ◽  
Vol 3 (15) ◽  
pp. 314-317
Author(s):  
Minoru KAWAMOTO ◽  
Tadakazu SAKURAI ◽  
Morio SEKI
Keyword(s):  
Permanent Deformation ◽  
Repeated Load
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