This study investigated the nanomechanical properties of asphalt binders modified with reclaimed asphalt pavement (RAP) using an atomic force microscope (AFM). RAP was blended at rates of 25%, 40%, and 60% with a virgin PG 64-22 asphalt binder. Both Superpave tests and AFM analysis found that adding more RAP increased the binder stiffness and high temperature grade. The 60% RAP blends showed over a 70% increase in elastic modulus compared to the unmodified binder. AFM also revealed changes in morphology and correlations between mechanical properties and nanostructure with RAP modification and aging.
Edgard Hitti with Granite Construction delivers a presentation on modified asphalt binders, including the benefits and proper use of binders, types used, and how they are tested and graded. Presentation delivered on Nov. 7, 2019 at the California Asphalt Pavement Association Fall Asphalt Pavement Conference in Sacramento, Calif.
Edgard Hitti with Granite Construction delivers a presentation on modified asphalt binders, including the benefits and proper use of binders, types used, and how they are tested and graded. Presentation delivered on Nov. 7, 2019 at the California Asphalt Pavement Association Fall Asphalt Pavement Conference in Sacramento, Calif.
One of our most highly rated presenters walks you through highlights of recent changes to Caltrans Section 39 asphalt specifications, including incorporation of elements of “Superpave” testing and acceptance. Toni Carroll is the Northern California Area Manager, Technical Services, for Vulcan Materials.
Presentation by Joe Peterson of Caltrans on the Caltrans move to "Superpave" delivered at the CalAPA Fall Asphalt Pavement Conference Oct. 24, 2013 in Sacramento, Calif.
Presentation by Cathrina Barros of Caltrans on Testing Accreditation and Independent Assurance delivered at the CalAPA Fall Asphalt Pavement Conference Oct. 24, 2013 in Sacramento, Calif.
Presentation delivered at the CalAPA Spring Asphalt Pavement Conference April 9-10, 2014 in Ontario. Topic: The use of Reclaimed Asphalt Pavement and Recycled Asphalt Shinges is explored in-depth.
Presentation by Dr. Adam Hand, University of Nevada, Reno, on the latest research and performance data on the use of RAP, RAS and other Durable Asphalt Pavement Mixes. Presentation delivered during the CalAPA Fall Asphalt Pavement Conference Oct. 26-27, 2016 in Sacramento, Calif.
Presentation by Bob Humer of the Asphalt Institute on "Recommendations for Mix Design Using RAP/RAS" for the CalAPA Spring Asphalt Pavement Conference & Equipment Expo, April 20-21, 2016, in Ontario, CA.
Dr. John Harvey, director, University of California Pavement Research Center, reviews the most recent research with regard to Reclaimed Asphalt Pavement during a presentation delivered during the CalAPA Spring Asphalt Pavement Conference March 7-8, 2024 in Ontario, Calif.
Mohamed Elkashef, Ph.D, representing the University of California, Davis Pavement Research Center (UCPRC) delivers a presentation on UCPRC's research related to the use of RAP in asphalt mixes. Presentation delivered on Nov. 7, 2019 at the California Asphalt Pavement Association Fall Asphalt Pavement Conference in Sacramento, Calif.
Presentation by the University of California Pavement Research Center on research results and recommendations for high RAP and RAS mixes in California. Presentation delivered at the California Asphalt Pavement Association (CalAPA) Regional Technical Committee meetings held April 3, 2019 at five locations via virtual meeting technology.
One of our most highly rated presenters walks you through highlights of recent changes to Caltrans Section 39 asphalt specifications, including incorporation of elements of “Superpave” testing and acceptance. Toni Carroll is the Northern California Area Manager, Technical Services, for Vulcan Materials.
Presentation by Joe Peterson of Caltrans on the Caltrans move to "Superpave" delivered at the CalAPA Fall Asphalt Pavement Conference Oct. 24, 2013 in Sacramento, Calif.
Presentation by Cathrina Barros of Caltrans on Testing Accreditation and Independent Assurance delivered at the CalAPA Fall Asphalt Pavement Conference Oct. 24, 2013 in Sacramento, Calif.
Presentation delivered at the CalAPA Spring Asphalt Pavement Conference April 9-10, 2014 in Ontario. Topic: The use of Reclaimed Asphalt Pavement and Recycled Asphalt Shinges is explored in-depth.
Presentation by Dr. Adam Hand, University of Nevada, Reno, on the latest research and performance data on the use of RAP, RAS and other Durable Asphalt Pavement Mixes. Presentation delivered during the CalAPA Fall Asphalt Pavement Conference Oct. 26-27, 2016 in Sacramento, Calif.
Presentation by Bob Humer of the Asphalt Institute on "Recommendations for Mix Design Using RAP/RAS" for the CalAPA Spring Asphalt Pavement Conference & Equipment Expo, April 20-21, 2016, in Ontario, CA.
Dr. John Harvey, director, University of California Pavement Research Center, reviews the most recent research with regard to Reclaimed Asphalt Pavement during a presentation delivered during the CalAPA Spring Asphalt Pavement Conference March 7-8, 2024 in Ontario, Calif.
Mohamed Elkashef, Ph.D, representing the University of California, Davis Pavement Research Center (UCPRC) delivers a presentation on UCPRC's research related to the use of RAP in asphalt mixes. Presentation delivered on Nov. 7, 2019 at the California Asphalt Pavement Association Fall Asphalt Pavement Conference in Sacramento, Calif.
Presentation by the University of California Pavement Research Center on research results and recommendations for high RAP and RAS mixes in California. Presentation delivered at the California Asphalt Pavement Association (CalAPA) Regional Technical Committee meetings held April 3, 2019 at five locations via virtual meeting technology.
Presentation by Dr. John Harvey, University of California Pavement Research Center, Davis & Berkeley, on Pavement Research and Practical Applications. Presentation delivered during the CalAPA Fall Asphalt Pavement Conference Oct. 26-27, 2016 in Sacramento, Calif.
Molecular Docking is the process of combining documents using bioinformatics techniques to enable the study of molecules. Useful especially in enzyme and ligand docking. This presentations uses Autodock Vina, Chimera and other related software packages
Responding to the public’s demand for more sustainable operations, many agencies are permitting ahigher percentage of Reclaimed Asphalt Pavement (RAP) in pavement mixes and are considering the use of Recycled Asphalt Shingles (RAS). Hear from a renowned national expert on the very latest in RAP and RAS trends, research and practical applications.
Simultaneous detection of nitrosamines and other sartan-related impurities in...TejasSonawane19
Since July 2018, the pharmacological class of “sartans” has been the subject of considerable media
and analytical interest, as it became known that they are contaminated with nitrosamines such as Nnitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA) and N-nitrosodiisopropylamine (NDiPA).
Previous compendial methods are not able to detect these new contaminants. Using the latest and innovative Quality-by-Design (QbD) approach, it has now been possible to develop an analytical method that
enables to investigate sartans, such as valsartan and losartan. Also a large class of different nitrosamines
in the ppb range and sartan-related impurities can thus be determined simultaneously in a single analysis
using supercritical fluid chromatography (SFC). By using SFC, a broad spectrum of nonpolar and very polar
impurities can be separated and analyzed in under 20 min. The analytical method developed is validated
for limit testing according to ICH Q2(R1) and fulfills default thresholds of EMA and FDA for testing of drug
substances and genotoxic impurities. Additionally, it can also be adapted to other pharmaceuticals that
may be contaminated with nitrosamines, since tetrazole synthesis as the underlying cause of nitrosamine
contamination is important for a set of other non-sartan drug substances.
Retrofitting of Beam-Column Joint using Carbon Fibre Reinforced Polymer and G...Satyam Vijay Bhosale
Retrofitting of an existing building is immensely essential for the deteriorated and damaged structure in Engineering and Medical fields. It refers to endowing the structure with a service level higher than that initially planned by modifying the structures, not necessarily damage area. Beam-column joints, being the lateral and vertical load transferring connections in reinforced concrete structures are particularly vulnerable to failures and hence the satisfactory performance of these joints is key to control the performance of connecting structural members during any event.
The project involves the study of the load carrying capacity of the beam-column joint after the application of the CFRP (Carbon Fiber Reinforced Polymer) and GFRP (Glass fibre Reinforced Polymer) sheets. Five beam-column joint models were cast out of which one model was the control specimen and others were cast for the purpose of the retrofitting. Four specimens were retrofitted by L-shape and straight configurations. The project focused on the effect of using the CFRP sheets and GFRP sheets for enhancing the strength and ductility of the beam-column joint. The wraps were provided to prevent the shear failure of the beam-column joint. The failure criteria including ultimate capacity, mode of failure, initial stiffness, ductility and developed ultimate strain in the reinforcing steel and respective sheet were considered and then compared.
At the California Asphalt Pavement Association (CalAPA) Spring “Technical Tune-Up” Educational Workshop held April 5, 2022 in Brea, a presentation titled, "Superpave Mix Design – What Agencies Need to Know" was delivered by
Dave Aver, QC Associate (ret), City of Santa Rosa.
In 2015, Caltrans adopted the “Superpave” mix design methodology for asphalt pavements. This session will
provide an overview of the Superpave method and provide the difference to the Hveem mix design methodology.
2022 CalAPA Spring Educational Workshop presentation on mix design
Rashid_Feroze_AState_2016_Poster
1. Nanomechanistic Investigation of RAP-Modified Asphalt
Binders by Using an Atomic Force Microscope (AFM)
Feroze Rashid1 and Zahid Hossain2
1M.Sc. Candidate at Arkansas State University and 2Assistant Professor of Civil Engineering
MOTIVATION & CHALLENGES
Addition of Reclaimed Asphalt Pavement (RAP) with virgin asphalts
alters the properties of base binders, resulting in different in-service
performance. However, Superpave tests are reported to have limitations in
characterizing modified asphalts. Hence, alternative tools such as Atomic
Force Microscope (AFM) have been utilized by pavement researchers and
professionals. In this study, binders from two field RAP samples were blended
at the rate of 25%, 40%, and 60% with a PG 64-22 binder and tested by
following conventional Superpave test protocols and an AFM technique. As
expected, the addition of RAP binder with the base binder increased the
stiffness, thereby increasing the high PG temperature up to 85oC for 60% RAP.
The elastic modulus of 60% RAP was over 70% higher than that of the base
binder, as found from the AFM tests. The modulus was found to be correlated
with the morphology. The nanoscale properties were in agreement with
microscale properties of the tested binders with more detailed results.
ABSTRACT
Understand atomic level properties of RAP
Waste into construction materials => Material sustainability
Facilitate constructing more durable and longer lasting pavements
Huge cost savings for taxpayers with low environmental impact
The FHWA promotes using RAP in new pavement construction
Overcome the limitations of Superpave Test Methods
Developed based on unmodified asphalts only
Does not consider molecular level properties event though asphalt is a
highly complex chemical with long chains of hydrocarbons
Reported to have limitations, specially in cases of modified asphalts
Recover asphalt binders from field RAP samples
Observe the micro-level changes of properties from the Superpave tests
Observe nano-level properties from AFM
Compare virgin versus RAP-modified binder properties
Correlate micro- and nano-level properties
OBJECTIVES
What is an AFM ?
• Atomic Force Microscope
• An advanced technology, nano-scale measurement
• Can get morphology and mechanistic properties at atomic level
AFM system Construction of Force-Distance Curve
Why AFM ?
• Can detect changes of nano-structures and phase differences
• Find correlations between mechanical properties and morphology
• Can visualize changes structure and properties
INTRODUCTION
Material collection (Field Core Samples and Virgin Binders)
Extraction and Recovery from RAP
Blending of RAP
Testing
Superpave
• Viscosity
• Complex
modulus
AFM
• Morphology
• Elastic Modulus
• Adhesion
• Deformation
AASHTO T 319-08
Aging
25%, 40%, and 60% RAP
RTFO and PAV Aging
TEST SETUP
Sample
Sample
Description
Source of
Materials
Remarks
Control PG 64-22
Ergon, Memphis,
TN
Unmodified
RAP-A
25%, 40%, and
60% by weight
I-30, Arkadelphia,
AR
Field performance
GOOD
RAP-B
25%, 40%, and
60% by weight
I-40, Russellville,
AR
Field performance
POOR
EQUIPMENTS AND MATERIALS
• Rotational Viscometer (RV)
• Rotational Thin Film Oven
• Pressure Aging Vessel
• Dynamic Shear Rheometer (DSR)
• Dimension Icon AFM
• PFQNMTM Mode
• RTESPA Probe
(25 N/m stiffness)
RESULTS AND DISCUSSION
0
500
1000
1500
2000
2500
135°C 150°C 165°C 180°C
Viscosity(mPa-s)
Temperature (0C)
Control
PG64-22+RAP-A(25)U
PG64-22+RAP-A(40)U
PG64-22+RAP-A(60)U
PG64-22+RAP-B(25)U
PG64-22+RAP-B(40)U
PG64-22+RAP-B(60)U
58
64
70
76
82
88
Control 25% 40% 60%
HighPGTemperature(oC)
Blend type (% RAP)
RAP-A
RAP-B
Change of Viscosity with the Amount of RAP
High Temperature (Rutting) Resistance
RESULTS AND DISCUSSIONS
• RAPs increased the high PG temperatures of blends
• 60% RAP-B increased the high PG up to180C
• Both RAPs improved the rutting resistance
• Addition of RAP-A produced 2.7 times extra
viscosity, which is 4 times for RAP-B
• RAP-B is stiffer than RAP-A
Control Binder
• Three distinct phases (Dispersed, Interstitial, and
Matrix; also called as Catana, Peri and Perpetua phase)
• Dispersed phase has lower area coverage DMT
(Derjaguin, Muller, Toporov) modulus ranged from
360 to 450 MPa
• Modulus of any specific aged blend
increases with the amount of RAP-A
• Modulus of any specific RAP-A blend
increases with aging
• RAP-A increases the modulus from
511 MPa (25%, unaged) to 803 MPa
(60%, PAV-aged)
Modulus of RAP-A BlendsMorphology of RAP-A Blends
• Changes in bees is an amplified
view of changes in the bulk (Ramm
et al. 2016)
• Bees change in size and number
with blend age and amount of RAP
• PAV aged binders have fewer bee
• Surface roughness varied from 50
nm to 70 nm
• The modification by RAP-B has
similar impact on the modulus as
RAP-A
• 60% unaged RAP-B blend showed
maximum increase (70%) in
modulus out of all unaged samples
• The maximum modulus for RAP-B
blend is 824 MPa (60%, PAV-aged)
Modulus of RAP-B Blends
Blend ratio and aging condition
DMT Modulus (MPa)
Average Adhesion
(nN)
Average
Deformation (nm)
Average of entire
specimen
Dispersed and
Interstitial
Matrix
Control Unaged 367 380 – 450 367 – 390 35.39 11.00
RAP-A
25%
Unaged 511 520 – 570 370 – 430 42.20 3.21
RTFO 580 610 – 680 450 – 510 41.30 4.97
PAV 583 570 – 700 380 – 530 32.70 3.70
40%
Unaged 590 520 – 730 425 – 500 36.75 3.84
RTFO 624 570 – 690 450 – 510 39.50 3.81
PAV 667 625 – 755 370 – 570 31.60 6.74
60%
Unaged 633 600 – 710 460 – 590 44.00 2.92
RTFO 675 594 – 765 380 – 550 34.00 5.96
PAV 803 820 – 970 620 – 670 22.60 3.26
RAP-B
25%
Unaged 536 570 - 605 420-460 37.40 5.82
RTFO 525 560 - 650 360 - 500 34.82 6.87
PAV 564 690 - 870 291 - 506 18.60 2.00
40%
Unaged 582 630 - 680 450 - 590 38.70 4.05
RTFO 616 685 - 720 475 - 600 28.25 7.07
PAV 757 875 - 1065 524 - 680 28.60 3.58
60%
Unaged 631 640 - 821 473 - 591 49.80 6.84
RTFO 632 612 - 863 492 - 611 37.50 3.60
PAV 824 744 - 985 495 - 690 28.00 5.65
• DMT modulus varied from 500 to 800 MPa for both RAPs
• RAP introduced extra adhesion while aging reduced it
• Increased adhesion after aging is due to the introduction of additional polar
molecules (Ramm et al. 2016), which is not true for all cases and could be
due to the result of reorganization of polar molecules
• RAP-blended binders had lower deformation than the control
• No specific trend of changes in the deformation values with respect to RAP
content or aging condition
• Stiff probe (spring constant 25 N/m) could be a reason behind not getting a
trend of change
• Effects of Rejuvenator: reduced average modulus values; increased
adhesion; reduced the stiffness; most of the “bee” structures disappeared
• Southern Plains Transportation Center (SPTC)
• Arkansas State Highway and Transportation Department
• Arkansas State University, University of Texas at Austin (Dr. Bhasin)
• National Science Foundation for the Major Research Instrument Award
• Suppliers of test materials
ACKNOWLEDGEMENTS
• Both of the RAPs increased the high PG temperatures of the blend
• Sixty percent (60%) RAP-B showed maximum 180C increment
• Control and RAP-A had three phases in the morphology while additional
small protrusions were noticed in RAP-B blends
• The control showed average modulus of about 350 MPa, which was 650
MPa in case of 60% RAP-modified binder
• Aging of asphalt further increases the modulus (around 800 MPa)
• Catana and Peri-phases showed higher modulus than Perpetua
• RAP modification and aging stiffen the binder
• Rejuvenator changed the structure and morphologies of the blend
• Rejuvenated blends showed lower modulus and stiffness, higher adhesion.
• Both of test methods showed consistent test results
• The AFM is a viable tool to characterize asphalt binder in a detailed
fashion
CONCLUSIONS
RejuvenatedRAP
40% RAP1
Unaged
702 610-800 700-780 10.2 1.56
Rej. RAP1 584 630 - 750 150-530 32 9.12
40% RAP2
Unaged
550 560-575 550-575 15.00 3.00
Rej. RAP2 410 420-500 90-350 23 3.00
40% RAP3
Unaged
637 635-660 570-630 15.57 3.65
Rej. RAP3 429 410-530 250-320 16 3.38
40% RAP4
Unaged
611 600-650 520-590 16.40 3.14
Rej. RAP4 304 300-340 170-245 20.6 1.52
• Observed small protrusions in
addition to three phases
• The dispersed phase diminishes as the
binders age for 25% and 40% blends
• For 60% RAP-B blends, bees were
almost absent
• The changes in RAP-B blends are
different than RAP-A blends
Morphology of RAP-B Blends