1、GEOTECHNICAL SPECIAL PUBLICATION NO. 268 GEO-CHINA 2016 RESILIENT RAILROAD MATERIALS AND STRUCTURES TO MITIGATE CLIMATE CHANGE SELECTED PAPERS FROM THE PROCEEDINGS OF THE FOURTHGEO-CHINA INTERNATIONAL CONFERENCE July 2527, 2016 Shandong, China SPONSORED BY Shandong University Shandong Department of
2、Transportation University of Oklahoma Chinese National Science Foundation Geo-Institute of the American Society of Civil Engineers EDITED BY Lubinda F. Walubita, Ph.D. Irina Holleran Aaron D. Mwanza, Ph.D. Published by the American Society of Civil Engineers Published by American Society of Civil En
3、gineers 1801 Alexander Bell Drive Reston, Virginia, 20191-4382 www.asce.org/publications | ascelibrary.org Any statements expressed in these materials are those of the individual authors and do not necessarily represent the views of ASCE, which takes no responsibility for any statement made herein.
4、No reference made in this publication to any specific method, product, process, or service constitutes or implies an endorsement, recommendation, or warranty thereof by ASCE. The materials are for general information only and do not represent a standard of ASCE, nor are they intended as a reference
5、in purchase specifications, contracts, regulations, statutes, or any other legal document. ASCE makes no representation or warranty of any kind, whether express or implied, concerning the accuracy, completeness, suitability, or utility of any information, apparatus, product, or process discussed in
6、this publication, and assumes no liability therefor. The information contained in these materials should not be used without first securing competent advice with respect to its suitability for any general or specific application. Anyone utilizing such information assumes all liability arising from s
7、uch use, including but not limited to infringement of any patent or patents. ASCE and American Society of Civil EngineersRegistered in U.S. Patent and Trademark Office. Photocopies and permissions. Permission to photocopy or reproduce material from ASCE publications can be requested by sending an e-
8、mail to permissionsasce.org or by locating a title in ASCEs Civil Engineering Database (http:/cedb.asce.org) or ASCE Library (http:/ascelibrary.org) and using the “Permissions” link. Errata: Errata, if any, can be found at http:/dx.doi.org/10.1061/9780784480113 Copyright 2016 by the American Society
9、 of Civil Engineers. All Rights Reserved. ISBN 978-0-7844-8011-3 (PDF) Manufactured in the United States of America. Preface This Geotechnical Special Publication (GSP) of the ASCE contains 17 papers presented at the GeoChina International Conference on Sustainable Civil Infrastructures: Innovative
10、Technologies for Severe Weathers and Climate Changes; held from July 25 to 27, 2016 in Shangdong, China. Topics covered in the book proceedings include: (1) Railroad Materials (2) Railway Structures, (3) Economics and Railway Operations, (4) Railway Construction and Maintenance, (5) Geological Disas
11、ter Control Technologies, and (6) Nanotechnology and Nanomaterials. In particular, the data/information contained in this GSP book will be found valuable to all those involved in the fields of Railway Engineering, Railroad Materials, Roads and Pavement Engineering, Geology, and Nanotechnology. Ackno
12、wledgments Douglas J. Wilson The University of Auckland, New Zealand Flor E. Sanchez University of Los Andes, Colombia Geoffrey S. Simate University of Wits, South Africa Glynn Holleran Fulton Hogan Ltd, New Zealand Hao PeiWen Changan University, China Hu SheZhong China Civil Engineering Constructio
13、n Corporation Mundia Muya University of Zambia, Zambia Sinthiya Ravi Texas A and Zahid Hossain, M.ASCE21Graduate Research Assistant, Arkansas State Univ., P.O. Box 1740, State Univ., AR 72467. E-mail: amferoze.rashidsmail.astate.edu 2Assistant Professor, Civil Engineering, Arkansas State Univ., P.O.
14、 Box 1740, State Univ., AR 72467. E-mail: mhossainastate.edu Abstract: Over 5.2 million tons of scrapped tires are produced each year in the United States. Disposal of this huge amount of scrapped tires has become a serious environmental issue. In recent years, scopes to use scrapped tire in the for
15、m of Ground Tire Rubber (GTR) in road construction projects have been analyzed as GTR has potential to improve asphalts performance from stiffness, resilience and shock absorbance perspectives. In recent years, some researchers have started using the atomic force microscope (AFM)-based nanoindentati
16、on technique to characterize pavement materials. In this study, the PeakForce Quantitative Nanomechanical Mapping (PFQNM) mode has been employed to analyze mechanistic properties and morphology of GTR-modified binders. A performance grade (PG 64-22) binder modified with two different grades (Mesh #3
17、0 and Mesh #40) of GTRs has been analyzed in this study. Nanomechanical properties such as adhesion, and DMT (Derjaguin, Muller, and Toporov) modulus for each blend have been quantified. Each sample was scanned at three different areas. Two distinct phases, namely, Catana and Peri-phase, were observ
18、ed in GTR-modified samples, although the DMT moduli were found to be in a close range. It was observed that modification of asphalt by GTR considerably changes the mechanistic properties of the base binder. INTRODUCTION With the advancement in time and technologies, the amount of vehicles in the Uni
19、ted States has been increasing at a faster rate, generating more than 300 million scrap tires each year (1). The most common forms of tire disposal are stockpiling, landfilling, and improper dumping, which pose serious environmental hazards as well as health concern. Accidental fire in stockpile wou
20、ld cause a disaster; trapped rainwater in tires provides a good breeding environment for mosquitos, flies and other insects. Moreover, after depletion of available land resources, new ways have to be found to process waste tires. The Environmental Protection Agency (EPA), in association with other a
21、gencies, has conducted several field trials to find out innovative and sustainable use of scrapped tires in lieu of stockpiling and landfilling. The main constituent of scrapped tire is mostly rubber of different forms (2); its use as Ground Tire Rubber (GTR) as an additive in hot mix asphalt (HMA)
22、could be a potential field to use scrapped tire in a sustainable way. *HR” the ratio between them being about two. Some researchers (9) suggested using DMT (Derjaguin, Muller, Toporov) Modulus of asphalt binder for characterization purposes, as it considers the adhesion values of the material, while
23、 the Youngs Modulus does not consider the materials adhesion properties. A few other recent studies (e.g., 10, 11) also estimated the DMT modulus of neat asphalt binders using different AFM systems. Asphalt is a viscoelastic material, which has considerable amount of adhesive properties; hence the D
24、MT modulus has been adopted in this study to find out the effect of GTR on strength properties of asphalt. The main goal of this study is to observe changes in morphology and important nanomechanistic properties (adhesion, elasticity, dissipation and deformation) of asphalt binders modified with GTR
25、. EXPERIMENTAL SETUP Among several modes of AFM, the Tapping mode is used to analyze the surface morphology of the specimen, while nanoindentation technique has been preferably used by researchers to find out the strength parameter of the material. In this method, indentations by sharp tips are perf
26、ormed at selected points of the samples and force-displacement curves are obtained for further analysis. A few researchers (12, 13) have reported difficulties of the nanoindentation technique to measure quantitative properties of asphalt. Allen et al. (12) concluded that improper *HR toothin specimr
27、 et al. (13)e because ochanical (Qanical Maps. It imagelculate diffhe construtip force ush the amoud corresponind out diffre 1(c). tion of Forcal three typable 1. Samf Mesh #30are measurchnique (15oplet was ps. Then the y AFM witon nitride led for at le. The smallntended to coscope Anahigh en as als
28、o f its NM) ping s the erent ction ed to nt of ding erent e es of ple 1 and e by , 16) laced glass hin a ever) ast 3 scan over lysis *HRel PG 64-PG 64-PG 64-S AND DIs researchenanoscale me named asphical illusgular area r depth) of tders. The Pto Catana,anomechnicfrom those oand 4 show0 GTR andcolum
29、n (a)TaSample De22 (Control22+15% GT22+15% GTSCUSSIONrs have reporphology:“Catana ortrations of tof the bindehe Bee strueri-phase is while the Pal propertief Catana orFIG. 2: Dithe data acqMesh #40 contains scble 1: Samscription ) R Mesh #3R Mesh #4orted the fo“bee structBee-phasehese phasesr surfac
30、e, cctures in thithe surrounderpetua-phas of asphaltPeri-phase.fferent moruired fromGTR modian results fople used in Ergo0 GTR0 GTRllowing thrures,” “adja,” “Peri-phaare provideontaining as phase is exing part of se is comprbinders in phological 10x10m sfied asphaltr Control sthis study on Asphalt t
31、hht of the surntrol. It is rmly distribhe sample sntrol sampleeri-phase halso found so0 blend, restion, dissipr height andodulus mapsthe Nanoscormat. control samesh #40 blp of the samounts. Catctures rangiderably, elimth of the GTe boundaryface irregulalso observuted over thurface havehave been d hi
32、gher adhme specialpectively. Aation and Dadhesion os for all samope softwaple), (b) 15ended withple surfaceana-phases ed up to 74 inating theR samples,between tarity of eached that the e surface ofbeen providseen to be lesion valuetraces of dtotal 5 chaMT Modulf all sampleples. The rere at the tim%
33、GTR MPG 64-22. For the Cowere seen tnm. The addPerpetua ponly two phhem was bof the modCatana and the sampleed in the selargely depens than that oifferent adhnnels us of s and sults e of esh ntrol to be ition hase ases eing ified Peri-. cond dent f the esion *HR a large value indicates a high non-el
34、astic behavior of the sample. The dissipation trend is found to be directly related to the adhesion force. Fischer et al. (10) found similar relation between adhesion and dissipation values. The Mesh #40 mesh GTR sample produced higher maximum value of dissipation than that of the control or Mesh #3
35、0 GTR. The DMT modulus (Figure 4) of the tested samples was also found to be related to the morphology. This trend can be seen clearly from the DMT modulus map of the Control sample. For the control sample, the Catana-phase and the Peri-phase of the control sample have similar magnitude of moduli, w
36、hich are lower than those of the Perpetua phase. The maximum value of DMT modulus for the neat binder is 90 MPa while this value increases up to 280 MPa for Mesh #30 GTR blended sample and 200 MPa for Mesh #40 GTR blended sample. Although the map for Mesh #30 GTR sample shows several peak (maximum a
37、nd minimum) values, the other modified sample (Mesh #40) exhibit almost similar values on the surface. Finally, it can be said that GTR has a notable impact on the DMT modulus of asphalt binder, increasing the maximum value by 200%. CONCLUSIONS To evaluate nanomechanistic properties of asphalt binde
38、r and modified asphalt binder, the AFM has been proved to be a viable machine for producing consistent results. The PeakForce Quantitative Nanomechanical Mapping (PFQNM) technique was found to be an effective and simple mode to obtain the desired nanomechanical data of asphalt binders modified with
39、ground tire rubber (GTR). The adhesion of the neat binder was found to be dependent on the morphology of the sample, while the deformation and dissipation values were directly related to the adhesion values. The GTR additive is found to produce significant changes in the microstructure of neat aspha
40、lt binder, diminishing the “Perpetua-phase” and overlapping the “Catana” and “Peri”-phases into one another. The adhesion, deformation and dissipation properties were affected by GTR additives, but the most affected one was the DMT modulus. The GTR-modified asphalts exhibited over 200% increase of t
41、he corresponding value of the Control sample. The findings of this study are expected to enrich the sciences related to nanomechanistic characterization of asphalt materials. . ACKNOWLEDGMENTS The authors acknowledge the supports from the suppliers of the binder and additives. *HR Dharamveer Singh2;
42、 and Siva Bohm31Research Scholar, Dept. of Civil Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India. E-mail: prabinashishiitb.ac.in 2Assistant Professor, Dept. of Civil Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India (corresponding author). E-mail: dvsi
43、nghcivil.iitb.ac.in 3Honorary Visiting Professor, Dept. of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076, India. E-mail: sivabohmiitb.ac.in Abstract: Asphaltic pavement suffers from major distresses such as rutting, and fatigue cracking. To mit
44、igate these problems, stiffer grade or binders modified with polymer or crumb rubber is being practiced. These modified binders are expensive and can pose storage stability problems due to phase separation at high temperature Recently, asphalt binder modified with organo modified nanoclay reported t
45、o be an excellent alternative to improve rutting and fatigue performance. The present study deals with rutting and fatigue performance of asphalt binder (AC-10) modified with organo modified nanoclay (CL-30B). Different percentages (0, 2, 4 and 6% by weight of binder) of CL-30B were mixed with AC-10
46、 using high shear mixer. Different performance studies such as Brookfield viscosity, Multiple Stress Creep Recovery (MSCR) and Linear Amplitude Sweep (LAS) were conducted on modified and unmodified binders. The results showed improvement in rutting and fatigue performance of asphalt binder with addi
47、tion of CL-30B. INTRODUCTION The rutting and fatigue cracking of asphalt binders are major distresses to asphaltic pavements. Generally stiffer grade or modified binders (Polymer modified, Crumbed rubber modified binder etc.) is desirable to have better rutting resistant. However, modified binders a
48、re expensive and can pose storage stability problems due to phase separation at high temperature (Pamplona et al. 2012). Recently, researchers have reported that organo modified nanoclay can provide an excellent alternative to these additives (Hossain et al. 2014). Previous research shows improvemen
49、t in rutting performance of organo modified asphalt binder based upon rutting factor (G*/Sin). However, limited studies have been conducted on rutting behaviour of nanoclay modified asphalt binder through Multiple Stress Creep Recovery (MSCR) test which have advantages over Superpave rutting factor test. In addition, the fatigue failure is another serious concern for asphalt binder, particularly in the low to intermediate temperature. Liu et al. (2011) conducted research on the fatigue performance of binder modified with organo modif
