Numerical and Graphical Method to Assess Permanent Deformation Potential for Repeated Compressive Loading of Asphalt Mixtures

2000 ◽  
Vol 1723 (1) ◽  
pp. 150-158 ◽  
Author(s):  
Rajesh K. Bhairampally ◽  
Robert L. Lytton ◽  
Dallas N. Little
Keyword(s):  
Strain Energy ◽  
Graphical Method ◽  
Permanent Deformation ◽  
Compressive Loading ◽  
Hydrated Lime ◽  
Numerical Approach ◽  
Empirical Models ◽  
Asphalt Mixtures ◽  
Deformation Potential ◽  
Repeated Load

Repeated-load permanent deformation testing has long been a popular way to characterize the performance of asphalt mixtures and to account for damage that leads to rutting. A number of empirical models have been used to fit repeated-load permanent deformation data. One such model, developed by Tseng and Lytton in 1989, fits permanent deformation data of most asphalt mixtures well. However, some mixtures exhibit a rate of damage that is in excess of that predicted by the 1989 Tseng and Lytton model. A numerical adaptation of the Tseng and Lytton empirical model is presented that readily characterizes such damage-susceptible mixtures. The excessive rate of damage is explained and reconciled in terms of plastic work theory and dissipated strain energy. The numerical approach is used to demonstrate the corrective effects of two types of additives to the mixtures: a recycled coproduct and hydrated lime.

Expedited Testing Program for Performance Characterization of Asphalt Mixtures

2019 ◽  
Vol 2673 (12) ◽  
pp. 225-233
Author(s):  
Intikhab Haidar ◽  
Charles W. Schwartz ◽  
Sadaf Khosravifar
Keyword(s):  
Permanent Deformation ◽  
Performance Testing ◽  
Testing Procedure ◽  
Test Methods ◽  
Asphalt Mixtures ◽  
Test Specifications ◽  
Research Grade ◽  
Repeated Load ◽  
Lengthy Process

The past two decades have seen significant efforts to standardize a series of simplified test methods to characterize the dynamic modulus (DM) and repeated load permanent deformation (RLPD) performance characteristics of asphalt mixtures using the asphalt mixtures performance tester (AMPT). While the current AASHTO T 79 test specifications for the AMPT are faster and easier to perform than their preceding research grade test protocols, there is still reluctance among highway agencies and industry to conduct performance testing using the AMPT. One significant reason is the lengthy process of sample preparation and testing for the DM and RLPD tests. Two studies to expedite this process are reported here. First, the potential for abbreviating the DM testing procedure was examined. It provides the option to fully exclude testing at 40°C by adding an additional frequency of 0.01 Hz at 20°C. This approach reduces time for testing as well as for sample conditioning at high temperature. Second, the possibility of reducing the total number of required specimens was evaluated. The variation of the DM under repetitive testing and the appropriateness of performing the RLPD test on samples already tested for DM were evaluated. The results showed that specimen damage or densification because of DM testing is insignificant. As a consequence, DM test specimens can be re-used for RLPD testing, reducing the required number of samples from 12 to 9.

Repeated compressive loading of a sand

1979 ◽  
Vol 16 (4) ◽  
pp. 798-802 ◽  
Author(s):  
P. N. Gaskin ◽  
G. P. Raymond ◽  
F. Y. Addo-Abedi ◽  
J. S. Lau
Keyword(s):  
Threshold Stress ◽  
Resilient Modulus ◽  
Permanent Deformation ◽  
Compressive Loading ◽  
Triaxial Tests ◽  
Failure Strength ◽  
Stress Cycles ◽  
Repeated Load ◽  
Static Failure

Twelve repeated load drained triaxial tests to at least 105 cycles on a sand are reported. A threshold stress of about 50% of the static failure strength was found. Below the threshold stress, the permanent deformation and resilient modulus reached constant values. Above the threshold stress, the permanent deformation began to increase rapidly and the resilient modulus to decrease as the number of stress cycles increased. The importance of keeping the traffic stress in the pavement below the threshold stress is outlined.

Permanent deformation response parameters of asphalt mixtures for a new mix-confined repeated load test

2013 ◽  
Vol 20 (5) ◽  
pp. 1434-1442 ◽  
Author(s):  
Gong-yun Liao ◽  
Yi-wen Yang ◽  
Xiao-ming Huang ◽  
Jin-yuan Xiang
Keyword(s):  
Permanent Deformation ◽  
Asphalt Mixtures ◽  
Load Test ◽  
Deformation Response ◽  
Repeated Load

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.

Laboratory Study on the Effect of Asphalt Emulsion as a Rejuvenator in Aged Asphalt Pavement

2012 ◽  
Vol 587 ◽  
pp. 57-61
Author(s):  
Rashid Tanzadeh ◽  
Mahyar Arabani
Keyword(s):  
Asphalt Pavement ◽  
Permanent Deformation ◽  
Asphalt Binder ◽  
Asphalt Mixtures ◽  
Asphalt Pavements ◽  
Laboratory Research ◽  
Asphalt Emulsion ◽  
Aged Asphalt ◽  
Repeated Load ◽  
Penetration Tests

Modification of the asphalt binder is one approach taken to improve aged pavement performance. To make the most of maintenance budgets, many agencies have resorted to the use of asphalt rejuvenators as an alternative to revive aging and brittle asphalt pavements. The purpose of this study is laboratory research on the effect of asphalt emulsion in restoring the original properties of aged asphalt pavement. For this purpose, the repeated load axial test is carried out on conventional asphalt samples and aged asphalt samples containing rejuvenator agents in different stress and rejuvenator percentage. Bitumen aged with RTFO according to ASTM-D2872 and the optimum bitumen of 5.5% were considered. The softening point and penetration tests, to examine the effect of rejuvenator in asphalt mixtures modification, On the basic, aged and modified aged bitumen were performed. The results represent that asphalt emulsion as a rejuvenator material in aged asphalt samples because of suitable performance improve aged asphalt permanent deformation resistance and aged bitumen Rheological property.

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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