Fundamental Properties of Asphalts and Modified Asphalts, III

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Work Conducted This Quarter A Topical Report, anticipated to be delivered early in the next quarter, summarizes findings from the past two to three years of research. This report describes the present state of practice for the investigation of the compositional nature of asphalts and aggregates, as studied by atomic force microscopy and presents modeling approaches for integrating asphalt/aggregate physichemical properties into continuum-damage models of pavement performance. Finally, this report will suggest how work elements from the ARC work plan; ARC Work Element Subtask M1b-2- Work of Adhesion at Nano-Scale using AFM, ARC Work Element Subtask M2a-2-Work of Cohesion Measured at Nano-Scale using AFM, Work Element Subtask F1d-7-Coordinate with AFM Analysis, and Work Element F3a-Asphalt Microstructural Modeling [Western Research Institute 2008], will be coordinated with this task. Work Plan Next Quarter • Research conducted to date in this subtask has been primarily concerned with defining and measuring compositional properties of material thin-films which exhibit and/or cause crazing phenomena. This is thought to be a result of material discontinuity (heterogeneity) caused by variations in wax and asphaltene content in the film. It is hypothesized that this heterogeneity may be considered an indicator of cracking and embrittlement in asphaltic materials. Thus, a natural avenue for future research would then be to conduct measurements at micron and nano-scale that focus more on physical/rheological properties of thin films related to the stiffness and embrittlement propensity, in addition to continuing compositional/chemical characterization of these materials, in order to draw correlations between compositional and rheological properties. • In the next quarter, a revised SARA separation method will be employed to separate asphalt into saturate, aromatic, polar aromatic, and asphaltene fractions. In this procedure, iso-octane asphaltene/maltene separations will be conducted, and the maltenes from this separation will be further separated employing the modified SARA separation procedure. Based on the information gained from these studies, a revised method for ASTM 4124 will be submitted to the ASTM D4 committee for approval. • A solidification stage is being assembled as part of the atomic force microscope by employing both a heating stage and a cooling stage fabricated along with micrometer positioning devices, figure 2-3.2. This apparatus will be used to impart a thermal gradient across an asphalt thin-film resulting in a moving solidification front (liquidsolid) interface that may be monitored in time with AFM. Furthermore, an automated wetting apparatus will also be assembled to better control the spin casting procedure and to observe and quantify lubrication dynamics (see figure 2-3.3). Finally, metrology and nanoindentation accessories have been added to the existing AFM equipment to enhance capabilities to include micro/nano-rheological testing of material thin-films. 50
a. Sample, b. cold stage, c. hot stage, d. micro positioner, e. micro positioner, ΔV- thermal controller, ΔT-digital thermoter. f. digital positioning stage on which the solidification stage sits Figure 2-3.2. Diagram of a proposed solidification stage to be assembled to work with existing AFM equipment 51
Page 1:
Fundamental Properties of Asphalts
Page 5: TASK 1. COORDINATION The goals of t
Page 8 and 9: Support of FHWA Strategic Goals The
Page 11 and 12: SUBTASK 2-2. AGING SUBTASK 2-2.1. I
Page 13 and 14: To further evaluate how water influ
Page 15 and 16: SUBTASK 2-2.2. SUPPORT OF THE MECHA
Page 17 and 18: Work Conducted This Quarter Introdu
Page 19 and 20: greater than 100 micrometers are co
Page 21 and 22: limestone. Major RA elemental oxide
Page 23 and 24: Log G* at 10 rad/s 8 7 6 5 25°C y
Page 25 and 26: Table 2-2.2.3b. Experiment status m
Page 27 and 28: Table 2-2.2.4b. Experiment status m
Page 29 and 30: (a) (b) PA Intensity (arbitray unit
Page 31 and 32: PA - Carbonyl total peak ht. (1700
Page 33 and 34: SHRP RA (granite) PA spectra of RA
Page 35 and 36: Mastics Several asphalt mastics wer
Page 37 and 38: 4000.0 3600 3200 2800 2400 2000 180
Page 39 and 40: • LTA1 (long term aging Level 1):
Page 41 and 42: The increase in carbonyl at the cen
Page 43 and 44: figure 2-2.2.19 to show the correla
Page 45 and 46: The majority of the results were pr
Page 47 and 48: Hirschfeld, T., 1976, Computer Reso
Page 49 and 50: SUBTASK 2-3. NANOTECHNOLOGY: AFM AN
Page 51 and 52: comprised of tens of thousands of d
Page 53: to the aggregate fine particle inte
Page 57 and 58: Problems and Solutions to Problems
Page 59: SUBTASK 2-4. LOW-TEMPERATURE PROPER
Page 62 and 63: Background The addition of polyphos
Page 64 and 65: All different aging times were shif
Page 66 and 67: Log a A 2.5 2.0 1.5 1.0 0.5 AAM-1,
Page 68 and 69: KAO Gripper. The minor resonance wa
Page 70 and 71: Dadey et al. [1988] proposed Scheme
Page 72 and 73: Problems and Solution to Problem No
Page 75: SUBTASK 2-6: VALIDATION SITE MONITO
Page 79: TASK 4. INFORMATION DEPLOYMENT SUBT
Page 83: SUBTASK 4-3. RESEARCH DATABASE—CO
Page 89: SUBTASK 4-5. SUPPORT OF THE MECHANI
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