| Priority |
Adequately
Addressed |
Needs
Improvement |
| |
| 1. Construction Issues (tender mixes, segregation, compaction, permeability) |
| 77 |
2 |
15 |
| Tender mixes need to be put to rest. Find a solution, even if it means recommending fine mixes |
| Permeability needs a standard test method. |
| What causes the tender zone? What compaction is needed to prevent permeability problems? |
| All of our coarse mixes have a permeability problem. |
| This is an asphalt issue, not just Superpave, that is a sleeping giant. |
| This is a critical area. |
| This also relates to N-des and VMA requirements. |
| We are concerned about permeability and its importance on pavement durability. |
| |
| 2. Mixture Strength Test |
| 77 |
3 |
13 |
| There is a desperate need for this. |
| Where is it? Superpave is implemented and there is no test. |
| ETG needs to make sure the research results are implementable. |
| ETG should get involved after NCHRP study is completed. |
| This may be the most critical need. |
| What is a good test? |
| NCHRP is looking at gyratory, field shear, and APA. We need something. |
| We need something that is simple, accurate, and available in the near future. |
| We need something now. Even ongoing projects will take time to evaluate. |
| NCHRP 9-19 is looking at this. There are several projects. Are they coordinated? |
| We need a strength test before the next millenium. |
| The number one issue is some sort of simple performance test - ASAP. |
| |
| 3. VMA Criteria and Effects with Different Aggregates and Gradations |
| 77 |
1 |
16 |
| We need to find realistic values that relate to performance - for Superpave not Marshall. |
| Is a maximum VMA needed? |
| Do coarse mixes need the same VMA as fine mixes? |
| VMA specified may be higher than needed. |
| Different aggregate sources may need different specifications. |
| It is impossible to achieve VMA with our aggregates that have good performance. |
| VMA has no "research" basis for Superpave. |
| VMA for coarse gradations is different than fine. |
| Should gradations above and below restricted zone have same VMA criteria? |
| This is related to N-des. Until N-des is settled, VMA research has little use. |
| This is a significant issue that needs action by the ETG and a formal NCHRP study. |
| |
| 4. AASHTO T 283 Moisture Damage |
| 73 |
4 |
13 |
| Current method needs to be dropped. |
| Lime slurry is used. Best practices needs to be developed. |
| We still do not have a moisture damage test after all these years. |
| Repeatability is a big issue. |
| Moisture damage is mysterious in many instances. |
| Validation needs to be addressed. |
| Procedure is too open. Either fish or cut bait with T-283. |
| With permeability problems, a moisture test is essential. |
| The ETG should do everything possible to get a reliable test procedure. |
| |
| 5. Field Verification Guidelines |
| 69 |
2 |
14 |
| What guidelines exist? Is anything being consistently followed? |
| We need some example specifications and acceptance payment schedules. |
| The NCHRP product is good but tries to do everything. It should be broken down into smaller pieces and be included in AASHTO Standards. |
| Has not been issued in standard AASHTO format. |
| What verification guideline exists? |
| States can handle this on their own. |
| |
| 6. N-design Refinement / Validation |
| 68 |
3 |
14 |
| N-des may need to be related to aggregate structure. |
| Does the current N-des levels ensure enough binder for durability? |
| Low volume roads need to be addressed. |
| Under traffic, does the mix compact down to 4%? This assumption needs to be answered before validation can occur. |
| The new N-des table needs to be validated. |
| The ETG should organize validation through ETG states. |
| Refinement of the N-des table was a step in the right direction. Validation is now needed - experimentally and in the field. |
| |
| 7. Gyratory Compaction Equipment (not all SGCs are the same) |
| 61 |
8 |
9 |
| This should be handled at the state level. A correction factor should be used. |
| Calibration procedure needs to be clear. |
| This is becoming a big issue. |
| Are we expecting too much from the SGC? This issue should be addressed because it is the primary measuring device for Superpave. |
| Calibration needs to be better addressed. |
| Method to calibrate is needed. |
| |
| 8. Forensic Investigations of Superpave Mixes (WesTrack rutting, Indiana flushing, Arizona moisture damage, etc.) |
| 58 |
7 |
10 |
| Better distribution of these investigations is needed. |
| These types of investigations provide the most useful information for the future. |
| Develop a standard format for reporting and investigating. |
| Information has not been well distributed. |
| There is a lot of hearsay. We need impartial fact finding efforts. |
| ETG cannot resolve these issues. |
| These efforts need to be more timely and have better distribution of results. |
| It takes forever to get a report out. |
| |
| 9. Flat and Elongated Test and Criteria |
| 56 |
1 |
16 |
| Does this relate to performance? 3:1 should be used. Use flat and elongated. |
| More efficient test device is needed. Procedure is not clear. |
| Is this test necessary? Does it relate to performance? |
| Aggregates in our state are not a problem. |
| The allowable percentage needs to be addressed. |
| The allowable percentage is too low. |
| 3:1 ratio should be investigated. |
| Need to get consistent date before making decisions. |
| Procedure and specifications are not in sync. |
| |
| 10. Superpave Performance Prediction Models |
| 51 |
5 |
11 |
| This has dragged on. Either commit to do it or abandon it for a new approach. |
| Most states know little about these models. |
| This will take a very very long time to complete. The ETG will be disbanded. |
| Is this realistic? |
| This is being addressed - maybe by 2005. |
| It is best to leave this one alone. |
| NCHRP 9-19 and 9-20 are addressing this issue. |
| |
| 11. RAP Usage |
| 49 |
9 |
8 |
| The mix and binder effects need to be addressed by the RAP specifications. |
| Effect on binder quality needs to be addressed. |
| Need to have better performance data. |
| Practical guidelines are needed - especially for the binder. |
| How does RAP effect high volume Superpave mixes? |
| NCHRP is doing something but more is needed. |
| Previous ETG guidance was adequate. |
| NCHRP 9-12 is evaluating this. ETG should review and make recommendations to AASHTO SOM. |
| |
| 12. AASHTO Provisional Standards - Test Procedures (TP) |
| 48 |
13 |
3 |
| There is a breakdown in communicating this information. |
| These issues need to be addressed more frequently. |
| Changes need to be balloted. Copies are hard to get in timely fashion. |
| ETG has done a great job in this area. Need to continue good work. |
| ETG should continue to review and comment on these standards periodically. |
| |
| 13. AASHTO Provisional Standards - Specifications (MP) |
| 47 |
12 |
4 |
| There is a breakdown in communicating this information. |
| This needs to be addressed more frequently. |
| These are tied to every other issue in this survey. |
| ETG should continue to review and comment on these standards periodically. |
| |
| 14. Integrate Mix Design and Pavement Design |
| 46 |
1 |
13 |
| This is an interesting approach. It may need to be integrated with warranties. |
| Great concept, but when will it be reality? |
| This needs to be based on in-place properties, which are different than QC field data. |
| Not sure this could become accepted nationally. |
| This is being addressed - maybe by 2005. |
| This is outside the scope of ETG. |
| Good luck. This needs flexible national guidelines so it can be modified on a regional basis. |
| |
| 15. Importance of N-max |
| 46 |
8 |
9 |
| N-max should be eliminated. |
| Does this relate to field performance? Is it needed? |
| Is N-max a needless step? |
| Does it actually mean anything? Should it be production criteria? |
| N-max should be eliminated until (if) its purpose can be demonstrated. |
| |
| 16. Importance of N-init |
| 45 |
8 |
9 |
| Is this related to field performance? |
| The change was good for low volume roads. More work is needed. |
| What is N-init supposed to do anyway? |
| Does N-init actually mean anything? Should it be a production criteria? |
| N-init should be eliminated until its purpose can be demonstrated. |
| |
| 17. New Technologies (ignition furnace, 2-D and 3-D imaging, etc.) |
| 45 |
9 |
7 |
| Ignition furnace correction factor needs to be addressed (especially with lime). |
| States need to know what is available so they can evaluate potentially useful technologies. |
| We need to be aware of these technologies. The ETG should focus on making what we have work better. |
| Use of ignition furnace and guidelines are a primary concern. |
| Let's focus on the basics before we get into 3-D. |
| Practical new technologies (ignition furnace) should be a top priority; impractical (virtual pavements) should not be considered. |
| It is good to keep the ETG informed. |
| |
| 18. Fine Aggregate Angularity Test and Criteria |
| 45 |
7 |
10 |
| Gsb is too variable to have an accurate test. FAA does not relate to performance. |
| Can the test be made to get results faster? |
| This does not correlate with performance. Stop spending resources on it. |
| The method needs to be specified. |
| We need one standard method. |
| Test has raised problems - Gsb |
| Flat and elongated fine aggregates test better. |
| Purdue University is conducting a pooled fund study, also NCHRP 4-19(2) |
| |
| 19. Gyratory Compaction Equipment - Ruggedness Testing |
| 44 |
11 |
5 |
| Superpave Centers should address this. |
| Sensitivity to intermediate sized aggregates needs to be addressed. |
| With one manufacturer in the state, this is not a problem. |
| If not all SGC are the same, then this step is mandatory. |
| Heights need to be controlled closer than standard indicates. |
| |
| 20. Compaction Slope from the Gyratory Compactor |
| 44 |
9 |
8 |
| Needs more research. |
| Is this a useful tool or not? More education is needed. |
| Basic research is needed. |
| NCHRP 9-16 is looking at this. |
| NCHRP 9-16 is looking at this. Some strength test is needed. |
| |
| 21. Superpave Software for Volumetric Properties |
| 44 |
11 |
6 |
| This will have little benefit to states. We are already using our own. |
| Where is it? We have already implemented Superpave. |
| What software? |
| Can we get the private sector to develop this? It has taken too long. |
| This needs to be more user friendly for technicians. |
| What software? The design was addressed, but what about the field? |
| The national software needs to allow for local criteria. |
| The software needs review, and then it needs to get on the street ASAP. |
| Where is it? It should allow for the design at different air void levels. |
| |
| 22. Restricted Zone |
| 41 |
11 |
6 |
| Should we respect the restricted zone or not? We need an answer. |
| If all other properties are met, what good does it do? |
| Each state should handle it on its own - let it be optional. |
| Addressed in NCHRP 9-14. |
| Addressed in NCHRP 9-14. ETG should make a recommendation to AASHTO. |
| It probably should be dropped. |
| |
| 23. Addressing the Use of Solid Additives in HMA |
| 39 |
8 |
8 |
| We need to be proactive to address this. |
| Solid additives are not allowed in our state. |
| Do fibers benefit the mix? |
| We need to know the impact on performance. |
| When a mix test comes, additives can be handled. |
| This is not a critical issue. |
| Previous ETG guidance was adequate. It should be reviewed and updated periodically. |
| |
| 24. Use of SMA with Superpave |
| 39 |
11 |
3 |
| This is being handled and works. |
| Maryland has handled this. |
| I thought Superpave was the answer. Why consider SMA? |
| The ETG should review this issue so research results can be incorporated into the various standards. |
| |
| 25. Lead States Guidelines |
| 38 |
12 |
3 |
| This is a good forum for introducing and screening changes. The ETG should follow the Lead State example. |
| A few of the issues needed more review and background information. |
| It is not clear who should take the lead on resolving conflict between AASHTO standards and Lead State Guidance. |
| |
| 26. Coarse Aggregate Angularity Test and Criteria |
| 37 |
9 |
6 |
| We need a better performance predictor than a "percent crushed" test. |
| This test is OK. |
| A non-subjective method is needed. |
| Procedure could use improvement. |
| NCHRP 4-19(2) is likely to investigate this. Results will not be available for some time. |
| |
| 27. Uniform Implementation of Superpave Nationally |
| 34 |
9 |
3 |
| Uniform implementation has not worked. |
| States want and need flexibility to use materials they have in order to produce economical mixes. |
| Would be nice but not a reality. |
| People will use what works best for them. If it is Superpave, then they will use it. |
| If there is something better, they will use that. |
| One size will never fit all conditions in this vast and diverse country. |
| Not a reality. |
| It is not happening unless we make it happen. We are always going to do what we want anyway. |
| A losing battle… |
| Is one set of criteria appropriate for the entire country? |
| |
| 28. IDT and SST Ruggedness Testing |
| 30 |
4 |
8 |
| There are still problems getting this equipment to work. |
| Most states know little about this equipment. |
| Adequate funding is required to come closer. |
| I don't know. |
| Is this over-engineering? Will this process work or even be cost effective? |
| IDT is OK. I have no hope for the SST. |
| Asphalt Institute completed this. |
| These tests seem impractical from a production point of view. |
| |
| 29. Please list other issues that you think are important that should be addressed by the ETG: |
| (3) What aggregate quality properties are really needed? |
| (3) Field QC/QA (VMA and performance test) |
| (2) Fatigue (especially with coarse mixes). |
| (2) Performance of fine mixes (they did better at WesTrack) |
| Proper mixing and compaction temperatures. |
| Proposed research from the Lead State Guidance regarding AASHTO T 166. |
| Proactive in collecting and exchanging data. |
| Conditioning of plant produced mixes. |
| Precision statement on TP-4. |
| Reduce variability of standard test procedures used for volumetrics, i.e. Gmb and Gmm. |
