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83 Question 1: Do you know the crude source of oil used to produce the asphalt binder and refining process employed? If yes, please identify the source. FIGURE A1 Respondents Familiar with Crude Oil Source Additional Responses to Question 1, âDo You Know the Crude Source of Oil Used to Produce the Asphalt Binder and Refining Process Employed?â Response A majority of the crude refined in our area is Canadian Bitumen, Axeon This is not something typically reported to VDOT. We do not manufacture PG Binder We do not specify crude sources be identified. We have a list of two pages of crude oil sources. We have lots of different sources of asphalt with as many different sources. Varies by supplier Our binder suppliers may be willing to answer this question and many of the following survey questions. CDOT is not involved with the production and formulation of the binders we use, and, with a few excep- tions, simply test according to the PG specifications in AASHTO M320. All of our binder suppliers are listed on CDOT's âApproved Products Listâ available online here: http://apps.coloradodot.info/apl/ SearchRpt.cfm?cid=Asphalt. I have tried to answer the survey questions to the best of my knowledge from the agency side, but I would suggest contacting the suppliers directly for more information. The refineries buy crude on the open market and sources change. Also the refineries will buy asphalt on the open market and blend it in with what they produce. In some cases, we do, but our intent is that the oil meet specifications testing, and so where it comes from falls toward non-essential information. It is mostly from Western Canada (heavy crude from Cold Lake and light crude from Alberta) but there could also be blend of light oil from states, Venezuela, Saudi, etc. APPENDIX A Survey Questions and Results
84 Question 2: What refining process was used to produce the asphalt? FIGURE A2 Refining Processed Used to Produce Asphalt TABLE A2 Survey Response to Question 2, âWhat Refining Process Was Used to Produce the Asphalt?â Process Response Rate Responses Distillation 32.6% 15: CA, CO, DE, FL, GA, IL, KY, MN, MO, ND, OK, SC, SD, TN, TX Residuum Oil Supercritical Extraction (ROSE) Continuous Air-Blowing 2.2% 1 ND Blending 19.6% 9: CA, DE, GA, MO, NC, ND, OK, SC, SD Other 2.2% 1 NE Do not know 67.4% 31 Total 46 Additional Responses to Question 2, âWhat Refining Process Was Used to Produce the Asphalt?â Response Air-blowing is not allowed in our spec. As an agency we do not know about the crude or refining process Blending has been done in the past but it is rare. Contact binder suppliers for more information. Multiple manufacturers, likely multiple methods Varies by supplier We do not manufacture PG Binder We have a performance specification that they meet. degrees of modification. Also, air blowing is not allowed unless specifically ordered as such. depends on suppliers there are several asphalt suppliers in Ontario. Many of them do blending of different grades. Basically it is how the refinery is set up and whether they are running gasoline or heating oil. I am sure there are other processes employed, but from an agency perspective we do not ask or specify.
85 Question 3: Have you observed significant differences in the asphalt binder PG properties derived from your oil feedstock in the past 10 years? FIGURE A3 Survey Responses to Question 3 Additional Responses to Question 3, âHave You Observed Significant Differences in the Asphalt Binder PG Properties Derived from Your Oil Feedstock in the Past 10 Years?â Response Changes in testing requirements have caused changes in the asphalt binder I've only been employed for 4 years and have not seen significant differences Less sticky/M320 results are often close to the lower limit of the acceptable range (cold end) Stiffer binders; varying penetration values, more sources than ever being used. They seem to have less âgoodiesâ than before. We do not refine. We donât think we see major differences for last 5-6 years. higher âloss on heatingâ values sulfur added to some binders I haven't noted significant changes, as materials are meeting specifications. At least one refinery seems to have issues at times with blending. Testing is similarâit meets the specs, but there are some pavements that seem to have prematurely aged. There have been instances where a few projects have experienced premature oxidation (visual observation). They continue to meet the specification so it can't be that different. Our spec has not changed much dur- ing that time. we are the agency. We have noticed premature cracking on our highways and believe that PG quality is a major player. We recently completed a survey and have an Excel file with BBR data that might show cold temperature property trends. We test the product after it has been processed to meet our specifications, so from the agency's viewpoint, the product does not change. None significant, but most of the grades we use today are different from what we used 10 years ago, so it is not an apples to apples comparison. The physical properties change and one can see it sometimes quarterly as feeds change. Also in 15 years the binders have gotten stiffer, poorer low temps.
86 Question 4: Are the asphalt binder PG properties varying with seasonal or market fluctuations? FIGURE A4 Survey Responses to Question 4 Question 5: What rheological and analytical procedures are you employing in your laboratory for asphalt binder testing? Please mark all that apply. TABLE A5 Rheological and Analytical Procedures Employed Procedure Response Rate Respondents Rheologyâperformance grade (PG) test protocol 100% 46 Iatroscan SARA analysis 0.0% 0 Fourier transform infrared (FTIR) 23.9% 11: AL, AR, FL, GA, IL, MN, MS, TN, TX, VA, WY Gel permeation chromatography (GPC) 4.4% 2: LA, VA Functional group analysis 0.0% 0 X-ray fluorescence (XRF) 19.6% 9: CO, FL, IL, MA, MN, NC, SC, VT, VA Other (Please specify) 2.2% 1: FL Question 6: Are you conducting any of the following binder fractionation procedures? If yes, please describe what triggered the decision to conduct this test. TABLE A6 Binder Fractionation Procedures Employed Procedure Response Rate Respondents Selective precipitation 0.0% 0 Column fractionation 0.0% 0 Iatroscan SARA analysis 2.2% 1 NE Gel permeation chromatography 4.4% 2: LA, VA Compatibility/phase separation 0.0% 0 Do not fractionate 23.9% 11: AZ, DC, FL, GA, ME, MA, MI, NC, OR, PA, TN No answer 69.6% 32 Total 46
87 Additional Responses to Question 6, âAre You Conducting Any of the Following Binder Fractionation Procedures?â Response CDOT is not, but suppliers may be. GPC, Others (FTIR) if needed (for research or forensic investigation). Not regularly. No binder fractionation procedures are being conducted. This is beyond the DOT function. We are not doing any fractionation. We do not perform any of the above. We do not refine. We have only done it for a research project to review the effects of rejuvenators on binders We do not fractionate the binder since it is a moving target. Years ago I worked on TLC as a quick test. Research facility (LTRC) developed a method using GPC to determine polymer percent in modified asphalt and examine asphaltene/maltene ratios. We have uncovered asphalt reaction with preservative treated woods resulting in liquefaction of bitumen. Further chemical investigation is planned. Question 7: Are you working on new procedures for separating various components of the asphalt binder? If yes, please describe your new procedure TABLE A7 Respondents Working on New Procedures for Separating Various Components of the Asphalt Binder Response Response Rate Respondents Yes 4.4% 2 LA, VA No 95.7% 44 Total 46 Additional Responses to Question 7, âAre You Working on New Procedures for Separating Various Components of the Asphalt Binder?â Response Contact binder suppliers for more information. I do have a process for separating and collecting asphaltenes, but no other component. Unknown We have an x-ray procedure to identify REOB and PPA presence and quantity. VTRC is utilizing GPC to study the effects of oxidation on binders as well as utilizing it as a potential forensic tool for VDOT. Question 8: What procedures are you using routinely to estimate asphalt binder aging characteristics? TABLE A8 Procedures Used Routinely to Estimate Asphalt Binder Aging Characteristics Procedure Response Rate Responses TFOT, RTFO 100.0% 46 PAV 100.0% 46 Multiple PAVâs 0.0% 0 Penetration index 4.4% 2: AL, AR Oven aging/phase separation 2.2% 1: AL Viscosity temperature coefficient 2.2% 1: AL Other 0.0% 0 Total 46
88 Additional Responses to Question 8, âWhat Procedures Are You Using Routinely to Estimate Asphalt Binder Aging Characteristics?â Response CDOT uses the standard RTFO and PAV aging procedures in AASHTO M320. Per Superpave Binder Specification These are the conditioning requirements to follow M320. We perform RTFO and PAV test for acceptance according to frequency guide. We use Extended BBR test for evaluating effect of physical hardening There are upper and lower limits on viscosity for the binder Abson recovered from RAP materials in our spec. Question 9: What procedures are you using occasionally to estimate asphalt binder aging characteristics? What conditions initiate the additional investigation? TABLE A9 Procedures Used Occasionally to Estimate Asphalt Binder Aging Characteristics Procedure Response Rate Responses TFOT, RTFO 40% 17 PAV 40% 17 Multiple PAVs 10.9% 6: FL, IL, IW, MA, MN, NE Penetration idex 4.4% 2: AL, AR Oven aging/phase separation 2.2% 1: AL Viscosity temperature coefficient 2.2% 1 AL ÎTc, fracture energy 2.2% 1: FL Glover-Rowe 4.4% 2: FL, OK Do not test 10.9% 6: CO, MI, MS, NV, PA, VA No answer 39.1% 18 Total 46 Additional Responses to Question 9, âWhat Procedures Are You Using Occasionally to Estimate Asphalt Binder Aging Characteristics?â Response A 3rd has looked at Glover-Rowe parameter when using rejuvenators in research projects. CDOT only uses the routine tests to estimate asphalt binder aging. FDOT is also looking some of new properties such as Delta Tc, Fracture Energy, Glover-Rowe, etc. FTIR for research No additional procedures are currently being used beyond what is used routinely. No additional testing is performed to estimate binder aging characteristics. Penetration index is part of our specification for some AC binders. The same procedures as the ones using routinely. We are starting to look into it on our rejuvenator project. We perform the standard PG testing for quality assurance testing. none. research done by a sub looking at multiple PAVs If by multiple PAVs it is meant that extended PAV aging is done on an additional sample, this has been considered/discussed in relation to asphalt extenders.
89 Question 10: Are you employing any of the following modifiers/additives in final binder preparation to achieve specific asphalt binder grades? TABLE A10 Modifiers/Additives Used in Final Binder Preparation to Achieve Specific Asphalt Binder Grades Additive Response Rate Responses Softening agents 21.7% 10: FL, LA, ME, MA, MO, NH, NC, OK, PA, WI Antistripping agents 26.1% 12: AR, DE, DC, KS, LA, ME, MN, OK, SC, TN, TX, WI Rejuvenators 10.9% 6: FL, KS, LA, MO, NE, OK Wax-based additives 15.2% 7: DE, FL, ME, PA, TN, TX, WI Polyphosphoric acid (PPA) 41.3% 19 Antioxidants 0.0% 0 Other 17.4% 8: AZ, KY, MI, UT, VT, VA, WV, WI No answer 32.6% 15 Additional Responses to Question 10, âAre You Employing Any of the Following Modifiers/Additives in Final Binder Preparation to Achieve Specific Asphalt Binder Grades?â Response As a user, we are not blending asphalts. We know suppliers are using some of these. Depends on suppliers N/A No air blown or PPA allowed unless approved by agency No, the supplier controls these materials. Softening agents and rejuvenators are only used for research projects. One supplier uses PPA. Specification call for use of SBS only 64-22 to 76-22 Suppliers using polymers as well This more suitable for terminals. We do testing for acceptance of project material. To our knowledge these items are being used by suppliers in this area. Unknownâquestion for binder suppliers We allow PPA up to 1.0% We do not manufacture PG Binder We do not refine. We don't typically require modifiers but some suppliers use them to meet specifications. We're not employing the additives, the suppliers are. manufacturers are not required to disclose maybe others, not sure The refineries make the AC to meet the specified grade. They have used PPA and will back blend with lighter stock. Compaction aids (waxes, wetting agents & antistrip) are paving related and dictated by the job, aggregate and plant. WMA Technologies (organic/wax based, chemical based (typically low water surfactant additive), water. The DOT does not prepare binders for use on projects. Missouri allows antistripping agents and wax-based additives (warm mix) but they are not used to achieve the desired binder grade. We have observed that some antistripping agent can affect the binder grade. We are looking into rejuvenators to achieve specific grades, and do allow PPA (at a max of 0.5% by weight of binder). The producers may be adding other additives to the binder to meet grade, but we only have specifications requiring or limiting some of them.
90 Response we have performed a pilot project using Evoflex. We have used Evoflex with a high recycle asphalt and it seemed to have graded back to a PG64-22. This was only on a trial basis and is not approved for full time use at this time. We don't actually manufacture the binders but I'm sure most of these are used by our suppliers. OR DOT does not monitor binder for any of the additives above, although suppliers may be utilizing one or more of the additives above. We require anti-strip for moisture-resistance properties, not grade modification. Companies have experi- mented with other modifiers (rejuvenators, softening agents, etc.). Antistripping agents are commonly used to meet TSR specification requirement. Rejuvenators have been used on 5 trial projects. We require antistripping additive for northern Ontario. We allow a limited quantity of PPA. We use a lot of PGXX-34 and some PGXX-40 therefore we know that softening agents (oils, etc.) are being used Contact binder suppliers for more information pertaining to specific formulations. PPA is currently not allowed in any binder used by CDOT. We allow SB, SBS, or SBR as modifiers. We also allow antistrip additives, but they are not commonly used. We suspect PPA is being used, but it isn't allowed by our specifications. We do not use liquid anti-stripping agents for on-system pavements. PPA/acid is restricted with less than 0.5% in our spec. Question 11: If you extracted binder from mixtures containing recycled materials, which mixtures have you examined? If yes, com- ment on your results. TABLE A11 Recycled Materials Extracted from Mixtures Recycled Material Response Rate Responses RAP 65.2% 30 RAS 47.8% 22 REOB 10.9% 6: FL, MI, NH, NC, OH, PA Rejuvenators 15.2% 7: NM, FL, KS, MO, NE, NY, VA RAP/RAS 4.4% 2: MO, NC No answer 26.1% 12: AL, AR, CO, DC, IL, ME, MA, MS, NV, NJ, UT, VT Total 46 Additional Responses to Question 11, âIf You Extracted Binder from Mixtures Containing Recycled Materials, Which Mixtures Have You Examined?â Response Binder extraction and grading has been performed on the rejuvenator trial projects. Binders sent out for spot checking of REOB CDOT does not test extracted binder. Difficult to obtain consistent grading, stockpiles of recycled materials change daily. Have also performed extractions on mixtures using both RAP and RAS. I hate post-consumer RAS but we have to use it. No RAS allowed PG binder grade testing PPA Performed by HMA Producer RAS has been and rejuvenators are planned to be studied on a trial basis. We are currently doing a research project analyzing extracted RAP binder and rejuvenators.
91 Response crumb rubber Polymer and Rubber have also been extracted with the understanding that Rubber particulates do get trapped in the filter paper. Typically done as a forensic investigation when issues during field production and construction occur. This work for RAS was due to legislative interest in allowing the use of RAS. Industry has also been showing interest in increasing the use of recycled materials. We haven't performed in-depth examination of extracted binder for recycled materials. We have used GPC to examine field core samples to verify polymer presence. We have extracted the asphalt from high recycle mixes mainly consisting of 9% RAP and 4% RAS to check the final grade of the asphalt. We will be checking more of these mixes this summer. Depending on the degree of aging, these mixes can be hard to distinguish from typical binder properties. See: http://l92018.eos-intl.net/L92018/OPAC/Common/Pages/GetDoc.aspx?ClientID=ML92018&Media Code=3073725 Question 12: If you are employing polymer additives, which type are you using? TABLE A12 Polymer Additives Employed Response Rate Responses SBS 71.7% 33 Radial (r-SBS) 15.2% 7: AR, LA, ME, NV, NJ, OH, SD (SBR) 26.1% 12: AR, CO, GA, KY, LA, ME, MI, NC, OH, SD, TN, TX Crumb rubber 30.4% 14: AZ, CA, GA, FL, GA, IL, LA, MO, NH, OH, OK, PA, SC, VA Polyethylene copolymers 0.0% Other plastomers 6.5% 3: NY, PA, SC Hybrid (GTR + SBS) 4.4% 2: AZ, FL No answer 17.4% 9: AL, KS, MS, ND, OR, UT, VT, WI, WY Total responses 46 Additional Responses to Question 12, âIf You Are Employing Polymer Additives, Which Type Are You Using?â Response Contact binder suppliers for more information pertaining to specific formulations. Limited tests on plastomersâHoneywell Products Not sure if SBS is linear or radial. Not sure if it's linear or radial SBS Our TR+ specifications require both SBS and Ground Rubber SBS & SBR. We test final grade se we do not necessarily know PG of base asphalt. Suppliers modify AC. The refineries are allowed to use SBS and SBR, and some of the others but not crumb rubber We do not manufacture PG Binders We do not specify type of polymers. It is up to asphalt suppliers We do not test for polymer additive types, only for PG qualification. crumb rubber is allowed, but has not been used Meeting our specification normally requires the use of SBS polymer. They are free to use what they want to meet the specification. Crumb rubber/wet blend rubber is being investigated on a trial basis. Polyethylene is allowed but not typi- cally used.
92 Response We are working on a county project that will use GTR. The base grade varied from PG 58-28 to PG 64-22 with a goal of PG 70-22 or better using 5, 10, 20% GTR by weight of binder. Other polymers are permitted in combination with the crumb rubber to produce a PG 76-22. Currently we are not told which polymer. We do not require a specific polymer, but require elastic recovery. No supplier of PG binders is currently using SBR. SBS (don't know what type), SBR, and Crumb rubber are being used. We specify meeting grades not spe- cific polymers. We specify a PG 64V-28 using any additive to make it. We specify SBR at 2% to result in a PG 70-28, Crumb Rubber is specified using ASTM D 6690 We don't restrict the types of polymers that can be used. Most asphalt-rubber binders are not PG graded. Other = approved use of Elvaloy, but actual use is very limited if any at all. We specify SBS block copo- lymers, but we have not specifically specified linear or radial, so we are unsure which type (linear or radial) asphalt binder suppliers are using. OR DOT uses AASHTO T301 with an elastic recovery requirement of 50% on RTFO conditioned binder. OR DOT does not monitor type of polymer utilized. Basically everyone in the area uses SBS polymers. The % varies with the crude. One plant makes a con- centrate and blends with 70-22 and the other uses 64-22 as the base. Question 13: If you are employing rejuvenators to restore aged asphalt binder, which type are you using? TABLE A13 Rejuvenators Employed to Restore Aged Asphalt Binder Rejuvenator Response Rate Responses Abietic acid esters (Hydrogreen) 10.8% 5: KS, KY, MO, NE, NC Aromatic oils (Cyclogen-L) 4.4% 2: NE, NY Soft asphalt binders 10.8% 5: AZ, FL, MN, NC, WY REOB 2.2% 1: FL, Banned in ME Evoflex 8.7% 4: KS, KY, MO, OK Soybean oil 2.2% 1: NE Lubricating/extender oils 2.2% 1: CO None 19.6% 9: DE, DC, GA, IL, IN, IW, MA, NV, PA No answer 47.8% 22 Additional Responses to Question 13, âIf You Are Employing Rejuvenators to Restore Aged Asphalt Binder, Which Type Are You Using?â Response Ingevity characterizes EVOFLEX CA as a âfatty acid derivative.â Also utilizing Evoflex sold by Ingevity. Choice would be up to producer but we ban recycled engine oil based products. DNA FDOT does not limit or specify the type of rejuvenator the producers may use. Hydrogreen and Evoflex have been the options on the rejuvenator trial projects. N/AâREOB banned No None Not sure if rejuvenators are being used and which ones, if used. These are for specific purposes and projects.
93 Response We currently do not specify rejuvenators. We do not manufacture PG Binders We do not specify rejuvenators We do not specify. I know softer binder and REOB are likely to be used We have experimented with Hydrogreen and Evoflex but have not accepted them for approved use. None Rejuvenators must meet ASTM 4552 Recycling Agent Rejuvenator agent is not allowed, except in hot in-place recycling and CIR projects (special provision only). The manufacturer of our ARA and ARA-1P rejuvenating emulsions, Ergon Asphalt & Emulsions, Inc., will be able to better answer this question. Have not started employing yet, but in research project we are looking at soybean oil, aromatic oil, and abietic acid esters. Question 14: How do you quantify the presence of modifiers/additives in final asphalt binder composition? TABLE 14 Procedures Used to Quantify the Presence of Modifiers/Additives in Final Asphalt Viscosity FTIR GPC MSCR XRF Do Not Measure Softening agents MO IL IL, NC, VT Antistripping agents SC DC, MO Rejuvenators MO Polymers MO, SC, TN, TX GA, IL, MS LA AZ, AR, KT, LA, ME NE, NV, NC, ND, PA, SC, TN, TX, VT AR, CO, IL, NE, NC, VT, WY Polyphosphoric acid (PPA) SC SC Recycled materials SC, TN, TX IL, ME PA, IN, TX N/A 28 Additional Responses to Question 14, âHow Do You Quantify the Presence of Modifiers/Additives in Final Asphalt Binder Composition?â Response 4C Ductility and Toughness and Tenacity AASHTO T 301 for polymers CDOT only uses the XRF to verify the lack of any PPA modification in our binders. Crumb rubber through certification. Antistripping agents measured on site. FTIR not internally but through outside entities occasionally Moisture-resistance testing on mix determines if adequate anti-strip additive is used. Polymers are usually most characterized by elastic recovery test. RecycledâNot commonly tested, restricted by aged binder in mix design We are beginning the process to start XRF testing We may start using XRF for PPA and REOB detection. We use â+â specsâphase angle, softening point, elastic recovery We use ER for polymer and PPA. XRF, GPC, and FTIR are being looked at for these types of applications. elastic recovery test for polymers we have specifications for polymers
94 Response Recycled materials such as RAP or RAS when blended with virgin binder, still need to meet the specified final grade of PG binder. Two PG+ tests: recovery and separation. Mandate amine-based antistrip addition during PQL and verifi- cation to assure binder won't change PG grade. We use AASHTO M 320 plus specification including elastic recovery, an original DSR phase angle requirement, and direct tension. We occasionally use wet chemistry for PPA. Amine anti-strips are easily detected with the nose. The ter- minal BOL is required to list all additives and modifiers. we test the final product for rheology. We have tried using XRF to detect PPA. It wonât give accurate results due to low dosage. We tried FTIR for antistripping agents. Similarly, the low dosage is hard to detect Field TSR (QC & QA) are required for acceptance; this is a check on the presence of antistripping agents. Daily binder samples are required. Samples are taken just prior to the binder entering the mixing drum and contain all of the additives, if used. DSR samples are performed on these samples to confirm the PG binder grade. The Missouri DOT has developed a test method for determining the amount of PPA used in the asphalt binder. Use this test when PG binder grade is not confirmed through DSR testing. Most of the additives, if requested, are based on a certified statement from the producer that they meet the specification requirements. We have limits on REOB and PPA. Otherwise, our spec does not require specific modifiers, except that we have an elastic recovery requirement. Question 15: Do you measure the compatibility between modifiers and asphalt final binder after storage or aging? Please cite the measurement technique employed in the comments box. TABLE A15 How Compatibility Between Modifiers and Asphalt Final Binder Is Measured After Initial Blending After Storage After Aging Do Not Measure Softening agents SC Antistripping agents SC MO, SC MO, SC SD Rejuvenators SD Polymers FL, IL, KS, SC GA, IL, LA, OH, SC SC SD Polyphosphoric acid (PPA) SC OH, OK, SC SC Rubber FL N/A 29 Additional Responses to Question 15, âDo You Measure the Compatibility Between Modifiers and Asphalt Final Binder After Stor- age or Aging?â Response ER only All binder must pass some type of stability/settlement test, regardless of composition. Contact binder suppliers for more information pertaining to specific formulations. No Supplier is relied upon to confirm compatibility of their formulations. We don't measure compatibility. We may run separation of polymer test after 48 hours of oven-aging. We sample and test the asphalt binder directly from the contractors HMA plant. We use the PG+ separation test. it is up to asphalt suppliers. We test the final product for compliance to our specifications. Compatibility as previous noted between wooden bridge decks and asphalt overlays may become an issue.
95 Response Missouri has one binder supplier that utilizes PPA. They indicate the use of PPA on the bill of lading and advise the asphalt paving contractor they are supplying so they can account for the use of PPA in the mix design. We have had a few jobs where the asphalt paving contractor was not aware of the presence of PPA. The PPA neutralized the antistripping agent which negatively affected the field TSR. The PPA also reacted with the polymer, negatively affected the PG binder. The PMA and PPA asphalts are stable in storage and never had a problem in the lab or the HMA plants. Our PG+ spec includes a separation tests which is a difference in DSR results. This is similar to the old cigar tube softening point difference method. After initial blending at terminal (source samples taken by supplier and DOT), after storage: samples taken from contractor storage tanks, after aging using PAV in Binder Lab. We rely on the asphalt binder suppliers to perform any compatibility testing with the specific crude sources they are using and any binder additives they are using to meet specified requirements. Polymer separation test (softening point difference) is performed for SBR and crumb rubber modified PG 76-22. Polymer elasticity is based on phase angle and MSCR %Recovery. A separation < 15F is required for the rubber binder (cigar tube test). No. PG binder need to meet the grade specified (with our ER requirement according to grade). Antistrip agents need to work to allow mix to meet Hamburg requirements. binder QA samples taken at HMA production facility on the day of mix production and need to meet spec, so this accounts for some storage time Question 16: If using an additive, what specifications are used for the amount of additive for a given grade? TABLE A16 Specifications Are Used for Additive Amounts Upper Limit Defined Minimal Required Specified Level Do Not Specify Amount Softening agents MN Antistripping agents PA, SC, VA FL, NC, ND, SD, TN, TX AR, DC Rejuvenators SD TX Polymers AZ, MI, NV CT, IL, OH, SC, TN Polyphosphoric acid (PPA) CO, FL, GA, IA, MA, MS, NE, PA, SC, TN, TX, WY Other (rubber) AZ, FL N/A 16 Additional Responses to Question 16, âIf Using an Additive, What Specifications Are Used for the Amount of Additive for a Given Grade?â Response Acid/PPA shall be less than 0.5% of the binder content. Anti-strip: 0.5% PPA: 0.75% Maximum Ground tire rubber: Min. 7% Antistrip: 1% Lime. PPA: 0.50 Max Antistripping agents are allowed but rarely used Binder grade and/or mix tests determine amount of modifier used. Maximum allowable for REOB and PPA No PPA is allowed in CDOT binder. Other: asphalt rubber by state specification Upper limit for REOBs We do not manufacture PG Binder We rely on ER test.
96 Response Levels of use for the most part are not specified but when additives are used I assume suppliers are dosing at a level of minimal needed for desired change. Anti-strip amounts come from the HMA plant. Polymer/PPA is very dependent on the crude source and the refinery determines the amount to meet the appropriate PG grade. Softening agents/rejuvenators the refineries probably use in blending to meet the PG grade. They are not used at the HMA plant. No amount is currently specified, XRF testing has indicated low presence of additives in MD supplied binders. We took two approaches during the rejuvenator trials: (1) specified level and (2) level defined by target grade for blended binder, Hamburg test and TSRST on mixture. Liquid antistripping agents are typically specified at a minimum level of 0.25% by weight of total binder in asphalt mixture or whatever the recommended minimum dosage is from antistripping agent manufac- turer. Polymer amount is determined by the asphalt binder supplier based on their crude stock, type of polymer, and production to meet the specified M335 grade (PG64E-22). PPA is typically specified at a maximum % of binder and is only specified as a polymer cross-linking enhancer or polymer catalyst, but this varies based on the polymer. (SBS vs. Elvaloy) Contractors have used Evotherm at a dosage rate typically of 0.5%. Evotherm has been used as an anti- strip agent and warm mix additive. Missouri focuses on the end result. They use whatever amount of antistripping agent is need to meet TSR requirements. Binder acceptance is based on meeting PG binder specifications. The supplier determines the amount of additives needed to comply with these requirements. Question 17: Are current PG grade criteria satisfactory in identifying compositional/chemical properties? If no, suggest criteria that should be added or changed. FIGURE A17 Current PG Grade Criteria Are Satisfactory in Identifying Compositional/Chemical Properties Additional Responses to Question 17, âAre Current PG Grade Criteria Satisfactory in Identifying Compositional/Chemical Properties?â Response Are we completely aware with how different components could affect binder performance? Current criteria are performance-focused. XRF may be logical criteria that could be added. Do not address durability. Do not use other additives in our binder Extended BBR, Extended PAV and DENT test FTIR Need existing equipment to tell us (XRF, FTIR, rheology) No opinion No suggestion Something to address adhesive properties of the asphalt binder Unknown. Unsure. We are in early stages of in-house researching XRF.
97 Response would likely need XRF testing or something similar to determine chemical composition The missing part is long-term aging. A one-point aging test like PAV does not tell us the whole story. In addition to M320 compliance, we require ash content not exceeding 0.8%. We also have acceptance criteria for MSCR, DENT, and ExBBR tests. We need to look at the chemical composition of our binders. It is my opinion that the PG64-22's are not the quality they used to be. This is based on the life of our asphalt pavements. MSCR % recovery identifies elastomeric polymer, but MSCR recovery curves were developed using SBS modifiers. Need additional curves for SBR, crumb-rubber, etc. if we are going to specify a % recovery for a specific Jnr (even more important if using the actual Jnr obtained rather than a maximum for a grade). We donât believe current PG grade criteria are satisfactorily identifying compositional/chemical proper- ties. REOBâs, PPA, etc. can go undetected in the PG grading system because it is purely rheologically based. The jury is very much out on how much any of these modifiers affect the long-term performance of the binder. It takes an actual examination of the chemistry to determine whether or not they are present. This one potential benefit of looking at utilizing Gel Permeation Chromatography (which weâre VTRC is doing) as well as employing our XRF at VDOT Materials to look at our binders. Delta Tc seems to be a quick method of using current test data to potentially identify a potential issue with low temperature cracking in asphalt binders. Any test should be quick and ideally based on current existing/common equipment. PG criteria have nothing to do with composition/chemical properties. PG criteria are physical criteria. A precise quantitative test procedure for type and % of REOB needs to be developed and standardized. We haven't had a problem using them to identify use of polymer, but trying to determine which additional tests to run, looking at SARA, AFM, FTIR, etc.to better analyze the binder. PG criteria currently seem to fail to capture some poorly performing binders. However, composition/ chemical properties are not of interest to us; we need good performance properties. CDOT uses the Ductility test (AASHTO T-51), Toughness and Tenacity test (Colorado CP-L 2210), and Elastic Recovery test (AASHTO T-301) as indicators for polymer modification on some grades of binder. A quick, easy field identification of modifiers (polymer & rubber) needs to be developed to determine what we are actually receiving on the job. The PG system or newer MSCR system does not identify chemistry. Basically fore either asphalt is some- thing that is black and sticky and has certain physical properties. For the most part current criteria measure physical properties which can indicate composition in some instances. It is satisfactory for the binder composition, the issues we see are more after the mix is put together and RAP is added. Question 18: Based upon internal research/knowledge, which physical properties are most sensitive to changes in the crude stock or binder chemistry? TABLE A18 Physical Properties Most Sensitive to Changes in the Crude Stock or Binder Chemistry Physical Property Response Rate Responses Initial rheology 26.1% 12 Aged rheology 34.8% 16 Ductility 13.4% 6 Forced ductility 10.9% 5 Elastic recovery 13.4% 6 Temperature susceptibility 4.4% 2 Stiffness 23.9% 11 Creep compliance 29.6% 8 Other 8.7% 4 No answer 43.5% 20
98 Additional Responses to Question 18, âWhich Physical Properties Are Most Sensitive to Changes in the Crude Stock or Binder Chemistry?â Response CDOT has not conducted any internal research on changes in crude or the chemistry of the binder. Don't have this knowledge within DOT Have not altered binder chemistry in the products we use It is up to our suppliers to know this. More appropriate to terminals or researchers. No opinion Toughness and tenacity We are not aware of when crude or binder chemistry changes. We do not deal with crude stock changes We do not manufacture PG binder We do not refine so no data vs crude stock Binder suppliers could probably give best answer to this question; we see final product Unknown Penn DOT does not know the crude stock of its asphalt binder suppliers or when or how often they may change this crude stock. Unknown. As an agency, we only specify for the end result. We do not get involved in the crude selection and changes. Asphalts using certain crude stocks (i.e., Mayan) may have difficulty meeting elastomeric requirements. Summer/winter blends may change properties as well when a refinery produces asphalt as a âside product.â As the crude stock varies and the main production product varies, so does the binder properties. Every- thing will meet a PG grade. However, the PG system was based on all pavements are made with 100% virgin binder. Using RAP/RAS means that not all PG binders are suitable. âDelta-Tâ may be related to âductility,â âstiffness,â and âcreep complianceâ Question 19: Is your laboratory developing alternate techniques to estimate binder performance? If yes, please summarize details FIGURE A19 Laboratory Is Developing Alternate Techniques to Estimate Binder Performance
99 Additional Responses to Question 19, âIs Your Laboratory Developing Alternate Techniques to Estimate Binder Performance?â Response Illinois DOT needs the ability to test for improved aging performance. Considering increasing the PAV aging time to identify poor performing asphalt. IDOT recently developed the IFIT SCB test to help iden- tify potentially poor asphalt mixes. Vermont DOT Is considering extended BBR, FTIR, DENT and DELTA Tc. West Virginia is Implementing MSCR Testing Michigan DOT is looking into MSCR New York DOT is starting to look more at mix performance tests Virginia DOT On-going research is studying GPCâs potential use as a performance indicator. Washington DOT is working toward implementation of AASHTO T 350 and M 332 including percent recovery. Florida DOT We are looking into the newer provisional standards, such as the LAS, tack test for the resi- due on the emulsions, binder fracture energy test recently developed by University of Florida Louisiana DOT LTRC research facility is our development arm for new techniques. We may participate in other ongoing research (i.e., NCHRP). Colorado DOT currently specifies the Ductility test (AASHTO T-51), Toughness and Tenacity test (Colo- rado CP-L 2210), and Elastic Recovery test (AASHTO T-301) as indicators for polymer modification on some grades of binder. Ontario MOT We have already implemented the DENT test (Double Edge Notch Tension Test-which is an AASHTO test now), MSCR, and Ash content (to limit REOB). We are phasing-in the ExBBR test (which is also an AASHTO Provisional test now). We are looking at XRF and FTIR tests to quantify REOB. We have also developed modified PAV procedure which is being evaluated at this moment. Question 20: What are your stateâs critical performance indicators for assuring good high-temperature performance? TABLE A20 Critical Performance Indicators for Assuring Good High-Temperature Performance Indicator Response Rate Responses G*sin Î´, RTFO 30.4% 14 DSR, RV 8.7% 4: DC, FL, LA, NY ASSHTO M320 21.7% 10 MSCR 13.0% 6: FL, LA, ME, NE, ND, WY APA, Hamburg 13.0% 5: GA, IL, KS, SD, WI MSCR + PG+ 4.3% 2: TN, TX No answer 13.05 6: AL, CT, IN, KY, NJ, NM Additional Responses to Question 20, âWhat Are Your Stateâs Critical Performance Indicators for Assuring Good High-Tempera- ture Performance?â Response PG high temp dynamic shear Binder complies with PG binder requirements (AASHTO M 320). Binders must pass high temperature PG grading. DSR G*/sin value equal to or greater than 1.0 at the specified test temperature. DSR on original and on RTFO binders (Phase angle, MSCR, etc.) Dynamic Shear G* and phase angle. G*/sin delta APA and Hamburg wheel tester for mixture G*/sin delta and the MSCR test
100 Response Grade choice is traffic dependent and we use either the PG or MSCR system to determine the initial binder grade. High temperature DSR meeting some minimum threshold. Initial DSR phase angle (replaced force-ductility) for presence of polymer, MSCR Jnr and % recovery (replaced elastic recovery). Jnr MSCR, original DSR and RTFO DSR. Meet PG and mix meets Hamburg Moving to performance testing of mixes, Hamburg wheel. Binder onlyâDSR/Jnr Original & RTFO DSR and elastic recovery Original DSR and MSCR PG grade upper limit, ER, rut testing. Penetration, ductility, viscosity and Marshall stability on asphalt concrete mix. Per the QC/QA asphalt binder program for NC, true grading of the binder is required for the high end DSRO, TRFO by the producer's AMRL lab. NCDOT also true grades the binder for samples received. This has been identified as an area of research for northern climates. Upper grading temperature on original and short-term aged binder (58, 64 or 70Â°C depending of the area and type of road). We are an M320 state with Direct Tension requirements deleted. We do not have rutting problem in Ontario. We rely on M320 results as well as MSCR compliance. rutting: agg properties, mix volumetrics, binder grads (on high end) and Hamburg (on some projects) we do not perform performance testing. Question 21: What are your stateâs critical performance indicators for assuring good intermediate-temperature performance? FIGURE A21 Critical Performance Indicators for Assuring Good Intermediate-Temperature Performance
101 TABLE A21 Critical Performance Indicators for Assuring Good Intermediate-Temperature Performance Indicator Response Rate Responses G*sinÎ´, PAVt 28.3% 13 ER 8.7% 4: CO, KS, OH, UT ASSHTO M320 15.2% 7: MO, NH, NY, NC, OK, OR, PA MSCR 13.0% 6: FL, LA, ME, NE, ND, WY MSCR + PG+ 4.3% 2: TN, TX Beam fatigue, AMPT 4.3% 2: GA, KS SCB 2.2% 1: WI No answer 30.4% 14 Additional Responses to Question 21, âWhat Are Your Stateâs Critical Performance Indicators for Assuring Good Intermediate- Temperature Performance?â Response Binders must pass intermediate temperature PG grading. DSR, BBR Elastic Recovery, Toughness and Tenacity, and PAV G*/sin(delta). Elastic recovery and PAV DSR. Fatigue cracking: binder elastic recovery and G*sin delta G* sin delta No spec currently for this G*sin delta Beam fatigue testing AMPT G*sin delta at PAV Intermediate DSR. Intermediate temperature DSR maximum, but our spec ties it heavily to the low temperature grade. M320 and DENT Moving to performance testing of mixes, Hamburg wheel, SCB. Binder onlyâDSR/Jnr Penetration, ductility, viscosity and Marshall stability on asphalt concrete mix. RTFO DSR > 2.2 There are no reliable tests out there to date. We are investigating some currently, but per PG Binder Spec- ification, we perform PAV DSR. We have an overlay test requirement on some mixtures (those that are designed to be more flexible). unknown We do not perform performance testing. Question 22: What are your stateâs critical performance indicators for assuring good low-temperature performance? TABLE A22 Critical Performance Indicators for Assuring Good Low-Temperature Performance Indicator Response Rate Responses BBR 34.8% 26 DSR 8.7% 4: DC, ME, MA, MN ASSHTO M320/M322 15.2% 7: MO, NH, NY, NC, OK, OR, PA MSCR + PG 13.0% 6: FL, LA, ME, NE, ND, WY No answer 17.4% 7: AL, CA, IL, IN, KY, NY, NJ
102 Additional Responses to Question 22, âWhat Are Your Stateâs Critical Performance Indicators for Assuring Good Low-Temperature Performance?â Response BBR and Direct Tension. We are also looking at different mix tests. BBR m-value (our binders seem to be creep-limitedâstiffness is generally well within limits) BBR maximum stiffness and minimum m-value. Almost all of our binders are m controlled. BBR stiffness value less than 300 MPa at a test temperature of â12 degrees Celsius. BBR m-value greater than 0.300 at a test temperature of â12 degrees Celsius. BBR, DSC Binders must pass low temperature PG grading. Ductility at 4C, BBR stiffness and m-value. Dynamic Shear and Creep Stiffness Lower grading temperature on long-term aged binder (â28Â°C, â34Â°C, or â40Â°C depending on area). Meet PG low on binder Moving to performance testing of mixes, DCT. Binder onlyâBBR No cracking in pavement in cold climate areas like the NC mountains PAV DSR < 5000 BBR: stiffness < 300, m value > 300 PAV TestingâBBR PAV-BBR PG low temp dynamic shear and creep stiffness. Penetration, ductility, viscosity and Marshall stability on asphalt concrete mix. Transverse cracking: binder grading (low end) evaluating DCT and SCB mixture cracking tests we do not perform performance testing. Question 23: Have you been able to identify field failures due to binder composition? If yes, describe failures. FIGURE A23 Can Identify Field Failures Due to Binder Composition
103 Additional Responses to Question 23, âHave You Been Able to Identify Field Failures Due to Binder Composition?â Response Have experienced issues with mixes using high amounts of RAP and RAS. I cannot recall anything specific to identify a failure. Is it foundation, poor construction or binder. Not by composition. Normally, identify issues related to the grade. Premature aging is seen sometimes. Is it binder? Maybe. Rapid embrittlement of mixes a couple of months after installation. Suspected, but never able to determine a smoking gun. Two research projects where cold-weather performance of PG 58-28 outperformed PG 52-34. Since there is no reliable field test, it is hard to determine if the failures can be attributed directly to the binder itself. We have had stripping, bleeding, segregation and other failures that have had binder âblamed,â but nothing definitive. We had a specification failure for DSR but not a field failure. PPA was used and with one ASA, it a true grade high temperature drop of 5Â°C. It was a chip seal emulsion that performed fine after placement, but the snow plows pulled up the emul- sion residue. The reason: excess diluent (diesel) Several mixes flushed/bled and did not set-up; binder composition with specific aggregate suspected as the cause; could not replicate issue in the lab Incompatibility between wood deck preservative and asphalt binders. Initial stages of failure identified. It is the opinion of our construction personnel that are binders are not of the quality they used to be 7â10 years ago. Our mix designs have basically not changed over the years, yet our asphalt mixes are only last- ing 7â9 years. It is apparent from inspection, that the polymer quantity or quality has changed over the last 7 years or so. Yes, and no on this question. At times the wrong binder has been supplied to a project or PPA was used with a limestone aggregate and was not compatible. In the past decade we noticed premature cracking (top-down mostly), starting in the wheelpaths and then propagating in a map cracking form. In many cases we recovered the binder and tested and noticed a great loss of low temperature grade (especially using ExBBR test) whis is an indication that the SHRP aging protocol is not sufficient on the low temperature side Question 24: What procedures have you used to remedy any field failures described above? Response No Answer (9) A Plan note was used on future project to allow no more than a 2C true grade drop. As explained earlier, we have introduced new advanced binder testing Change spec limits, change mix types etc. Disallow the use of REOB or other recycled oils. FDOT is looking into developing a field test for determining polymer/rubber presence and possibly quan- tity. This is to try and prevent dilution at the plants and ensure that we are getting the high performing binder that we have asked for by design. Fog seal, remove and replace. Have lowered the amount of RAP and RAS that can used in bituminous mixtures. If it is something related to raveling or top down cracking, we tried fog seals with rejuvenator.. Proposed procedureâremoval. Remove and Replace (2) Sent asphalt binder samples to TFHRC for REOB analysis. Take good samples. We have discussed the possibility of adding 0.2% virgin binder to our asphalt mixes and study them over a few years to see if this aids in longer pavement life. case by case
104 Question 25: Are you conducting ongoing research on binder characteristics that is not covered above and that you would be willing to share? If yes, please provide contact information. FIGURE A25 Conducting Ongoing Research on Binder Characteristics That You Would Be Willing to Share Additional Responses to Question 25, âAre You Conducting Ongoing Research on Binder Characteristics That Is Not Covered Above and That You Would Be Willing to Share?â Response Connecticut DOT is not currently conducting research on binder characteristics. Virginia DOT for GPC. Contact Ben Bowers: firstname.lastname@example.org Nebraska Department of Roads Please contact Robert Rea at 402-326-9934 to discuss further. Rhode Island DOT Contact Professor Michael Greenfield URI email@example.com Iowa DOT Rejuvenator research with David Lee at University of Iowa Oklahoma DOT Very early stages of in-house XRF testing for PPA and REOB. Texas DOT Contact Tom Scullion, Texas A&M Transportation Institute; Amit Bhasin, Center for Trans- portation Research at UT. Ohio DOT Just started binder/RAS/RAP study with Ohio University, Dr Munir Nazzal. Just started mix RAS/RAP cracking study with NCAT. Wyoming DOT. I performed research on asphalt binders at WRI for roughly the last 11 years. Lead author on about a dozen peer reviewed papers. Have a lot of ideas on binder research firstname.lastname@example.org Comments Provided by Canadian Respondents Question 1: Do you know the crude source of oil used to produce the asphalt binder and refining process employed? If yes, please identify the source. Commentsâ Ontario: It is mostly from Western Canada (heavy crude from Cold Lake and light crude from Alberta) but there could also be blend of light oil from states, Venezuela, Saudi, etc. SK Grade A crude typically from western Canada Question 2: What refining process was used to produce the asphalt? Commentsâ there are several asphalt suppliers in Ontario. Many of them do blending of different grades. Question 3: Have you observed significant differences in the asphalt binder PG properties derived from your oil feedstock in the past 10 years? Commentsâ QC: We didnât observed differences in the PG properties, but we have observed differences in the MSCR results Ontario: We are the agency. We have noticed premature cracking on our highways and believe that PG quality is a major player Question 4: Are you conducting any of the following binder fractionation procedures? If yes, please describe what triggered the
105 decision to conduct this test? Commentsâ Question 5: What rheological and analytical procedures are you employing in your laboratory for asphalt binder testing? Please mark all that apply. GNB: Functional group analysis Question 6: Are you conducting any of the following binder fractionation procedures? If yes, please describe what triggered the decision to conduct this test. NT: FTIR Compatibility/Phase separation NS: No fractionation procedures are conducted as part of the Departmentâs Quality Assurance program BC: We have uncovered asphalt reaction with preservative treated woods resulting in liquefaction of bitumen. Further chemical investigation is planned. SK: we are not conducting any of the binder fractionation procedures mentioned Question 7: Are you working on new procedures for separating various components of the asphalt binder? If yes, please describe your new procedure. Commentsâ Question 8. What procedures are you using routinely to estimate asphalt binder aging characteristics? Commentsâ Ontario: We use Extended BBR test for evaluating effect of physical hardening Question 9. What procedures are you using occasionally to estimate asphalt binder aging characteristics? What conditions initiate the additional investigation? Commentsâ Question 10. Are you employing any of the following modifiers/additives in final binder preparation to achieve specific asphalt binder grades? Commentsâ We require antistripping additive for northern Ontario. We allow a limited quantity of PPA. We use a lot of PG XX-34 and some PG XX-40 therefore we know that softening agents (oils, etc.) are being used. QC: Additives may be used by the asphalt binder suppliers to achieve our specifications. We do not request additives. NL: Liquid antistripping agents are used in all binders but not to achieve PG grades. Question 11: If you extracted binder from mixtures containing recycled materials, which mixtures have you examined? If yes, com- ment on your results. Commentsâ QC: The use of 20% or less of RAP has a low impact on the asphalt binder properties Question 12: If you are employing polymer additives, which type are you using? Commentsâ SK: SK does not use PG grade asphalt binder; typical asphalt used is 150â200 and 200â300. Rubber asphalt binder has been used in past. the base grade is 200â300 pen which is modified by addition of crumb rubber. Ontario: We do not specify type of polymers. It is up to asphalt suppliers QC: The majority of our asphalt binders are modified with polymers. The presence of polymers is controlled by an elastic recovery test. The suppliers choose the type of polymer used to meet the elastic recovery specification. SK: lime is used as anti-stripping agent for asphalt concrete mixes. Question 13: If you are employing rejuvenators to restore aged asphalt binder, which type are you using? Commentsâ QC: No rejuvenators are used. A maximum of 20% of RAP and 3% of RAS are allowed in our mix.
106 NS: Rejuvenator used for cold in place recycling treatments SK: cyclogen has been used on few occasions in past. Question 14. How do you quantify the presence of modifiers/additives in final asphalt binder composition? Commentsâ Ontario: We test the final product for rheology. We have tried using XRF to detect PPA. It wonât give accurate results due to low dosage. We tried FTIR for antistripping agents. Similarly, the low dosage is hard to detect. NS: Any additives need to be identified on weigh tickets Question 15: Do you measure the compatibility between modifiers and asphalt final binder after storage or aging? Please cite the measurement technique employed in the comments box. Commentsâ Ontario: It is up to asphalt suppliers. We test the final product for compliance to our specifications. QC: It might be done by the suppliers. Not by the Ministry. Question 16: If using an additive, what specifications are used for the amount of additive for a given grade? Commentsâ QC: The amount of additives used is determined by the suppliers. The final product shall meet all the specifications. Question 17: Are current PG grade criteria satisfactory in identifying compositional/chemical properties? If no, suggest criteria that should be added or changed. Commentsâ Ontario: In addition to M320 compliance, we require ash content not exceeding 0.8%. We also have acceptance criteria for MSCR, DENT, and ExBBR tests. QC: The PG grade is useful to evaluate the performance of binders at high and low temperatures, but itâs not a direct relationship between the rheology of the binder and the chemical composition of the binder. Other properties such as the elasticity and the adhe- sivity of the binder must be considered. SKL: Not applicable as PG grades are not used in SK. NL: For polymer grades MSCR or elastic recovery could be specified. Question 18: Based upon internal research/knowledge, which physical properties are most sensitive to changes in the crude stock or binder chemistry? Commentsâ Question 19: Is your laboratory developing alternate techniques to estimate binder performance? If yes, please summarize details. Commentsâ Ontario: We have already implemented the DENT test (Double Edge Notch Tension Test-which is an AASHTO test now), MSCR, and Ash content (to limit REOB). We are phasing-in the ExBBR test (which is also an AASHTO Provisional test now). We are looking at XRF and FTIR tests to quantify REOB. We have also developed modified PAV procedure which is being evaluated at this moment. QC: We have a method to measure the ash content of the binders. We also have a method to evaluate the adhesivity between a binder and an aggregate. For some binders, we added some criteria with this method in our specifications to be sure to get a binder with superior adhesive properties. These binders help to reduce stripping problems of the pavements. Question 20: What are your stateâs critical performance indicators for assuring good high-temperature performance? We do not have rutting problem in Ontario. We rely on M320 results as well as MSCR compliance. BC: This has been identified as an area of research for northern climates. QC: Upper grading temperature on original and short-term aged binder (58Â°C, 64Â°C, or 70Â°C depending of the area and type of road).
107 NS: Dynamic Shear SK: Penetration, ductility, viscosity and Marshall stability on asphalt concrete mix. NL: PG high temp dynamic shear Question 21: What are your stateâs critical performance indicators for assuring good intermediate-temperature performance? NS: Dynamic Shear SK: Penetration, ductility, viscosity and Marshall stability on asphalt concrete mix. Question 22: What are your stateâs critical performance indicators for assuring good low-temperature performance? SK: Penetration, ductility, viscosity and Marshall stability on asphalt concrete mix. QC: Lower grading temperature on long-term aged binder (â28, â34 or -40Â°C depending on area). NS: Dynamic Shear and Creep Stiffness NL: PG low temp dynamic shear and creep stiffness Question 23: Have you been able to identify field failures due to binder composition? If yes, describe failures. Commentsâ Ontario: In the past decade we noticed premature cracking (top-down mostly), starting in the wheelpaths and then propagating in a map cracking form. In many cases we recovered the binder and tested and noticed a great loss of low temperature grade (especially using ExBBR test) this is an indication that the SHRP aging protocol is not sufficient on the low temperature side Question 24: What procedures have you used to remedy any field failures described above? Ontario: As explained earlier, we have introduced new advanced binder testing Question 25: Are you conducting ongoing research on binder characteristics that is not covered above and that you would be willing to share? If yes, please provide contact information. Commentsâ