Region 2: Materials
The Materials Division has the responsibility for pavement management and pavement design. The division monitors, tracks, and performs analysis on pavement in the region two highway network. The materials division is also responsible for developing and overseeing materials related specifications for construction projects.
The division oversees the materials testing and acceptance programs in Region Two. It maintains the required laboratory testing certifications, accreditations, and testing equipment calibrations needed to qualify for federal funding eligibility. The division also performs mix design verifications of asphalt and concrete for use on construction projects and acceptance testing for concrete compressive strength.
Goal: Specification Improvement
- Concrete for bridge decks
- PCCP - Special Provision Update
- HMA acceptance testing - using contractor QC tests
Concrete for Bridge Decks
Revised requirements for bridge deck concrete. Revisions include reduced allowable shrinkage to .03 percent, reduced water/cement ration to .40 and the addition of fibers to mix (4 lbs macro fiber and 2 lbs fibrulated fiber per yard). These changes should help mitigate issues UDOT is currently experiencing with shrinkage cracks on the bridge decks. UDOT Structures Division is pursuing changes to the Standard Specifications which incorporate these requirements.
PCCP - Special Provision Update
Over the last few years we have utilized several different versions of a special provision for PCCP on the projects. This year we have combined all of the changes, incorporated lessons learned, and updated the special provision. The main changes moving forward are:
1. Use of thickness cores for compressive strength acceptance. This will reduce the work load of testing technicians and reduce the testing issues associated with preparing concrete cylinders.
2. Requirement of steel verification updated to a frequency of 1/3 of steel placed and clarification of equipment used for varification.
3. Requirement of sand equivalent of 75. This should reduce issues we have encountered with inconsistent concrete strength.
4. Requirement of optimized gradations. This should provide a better overall mix with increased durability.
HMA acceptance testing - using contractor QC
This year we developed a special provision that provides for the use of contractor QC tests being incorporated into the acceptance testing after UDOT validates the contractor tests are consistent with those performed by UDOT. This should reduce the work load on UDOT testing technicians as well as encourage closer monitoring of the contractor QC test results. These should help provide a more consistent product.
Require use of rapid setting concrete for utility adjustments
This year we have required the use of rapid setting concrete on the utility adjustments within asphalt mill and fill paving projects with high volume traffic. This will allow UDOT to reopen the travel lanes to traffic without the use of steel plates to cover the concrete while it cures for 7 days. Initially, it is expected to be more expensive than traditional methods but as industry adapts, the costs are expected to decrease.
Goal: Update/Maintain Region Lab and Field Labs Testing Equipment
- Upgrade Nuclear Density Gauge storage area
- Upgrade Asphalt Rice machines
- Upgrade core saw for project crews
- Replace Pavement Coring Rig
Upgrade Nuclear Density Gauge Storage area.
Region Two has 28 Nuclear Density Gauges. The number of gauges has exceeded our ability to store and care for the gauges. Currently, the gauges are stacked 3 high in each locker. This makes it difficult for the technicians to lift the gauges into the lockers. Plans are underway to extend the existing building to provide adequate room to secure and store the gauges. This should be completed by the end of the fiscal year.
Upgrade the Asphalt Rice machines.
We have purchased an AutoRice machine for each project crew materials lab. Last year we purchased two of these machines to try out in the Region Materials Lab. It is widely known that the theoretical maximum specific gravity (Rice test) is one of the most important tests in the asphalt industry. Rice test results are critical for pavement quality, mixture design, and laboratory mixture performance determination. This machine automatically controls vacuum pressure and vacuum time, and monitors shaker vibration frequency. This machine can help achieve better accuracy and repeatability. The cost to equip the project crew labs is $11,498.
Upgrade the core saw for the project crews
The current saws are old and are becoming a safety hazard to operate. Further they are not large enough to cut six inch diameter core samples. The cost of the saw was $3889.