Specification Criteria for Simple Performance Tests for Rutting, Volume I: Dynamic Modulus (E*) and Volume II: Flow Number and Flow Time

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.

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Effect of FORTA-FI Fibers on the Rutting Potential, Dynamic Modulus, Flow Number, and Fatigue of Asphalt Concrete

10.33915/etd.6524 ◽

2018 ◽

Author(s):

Elbert Rohrbough

Keyword(s):

Asphalt Concrete ◽

Dynamic Modulus ◽

Flow Number

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

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1832-25 ◽

2003 ◽

Vol 1832 (1) ◽

pp. 209-216 ◽

Cited By ~ 24

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.

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Etching of Polymers by Oxygen Plasma

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101797 ◽

1968 ◽

Vol 26 ◽

pp. 408-409

Author(s):

Virgil Peck ◽

W. L. Carter

Keyword(s):

Molecular Weight ◽

Oxygen Plasma ◽

Flow Time ◽

Microscopical Study ◽

Surface Layers ◽

Organic Vapors ◽

Sample Position ◽

Accuracy Of Measurement ◽

Bulk Polymers ◽

Electron Microscopical

Any electron microscopical study of the morphology of bulk polymers has throughout the years been hampered by the lack of any real ability to produce meaningful surface variations for replication. True etching of polymers should show crystalline and amorphous regions in some form of relief. The use of solvents, acids, organic vapors, and inert ion bombardment to etch samples has proved to be useful only in limited applications. Certainly many interpretations of these results are subject to question.The recent use of a radiofrequency (R. F.) plasma of oxygen to degrade and remove organic material with only minor heating has opened a new possibility for etching polymers. However, rigid control of oxygen flow, time, current, and sample position are necessary in order to obtain reproducible results. The action is confined to surface layers; the molecular weight of the polymer residue after heavy etching is the same as the molecular weight of the polymer before attack, within the accuracy of measurement.

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