Specification Corner

Alabama DOT
Evotherm is now allowed as a WMA additive. RAP is no longer allowed in OGFC. We have added a specification for thin lift HMA. We have two pilot projects for performance based mix design on local (county) roads that will let in 2020 and the associated tests are Ideal-CT and High Temperature IDT.

Colorado DOT
CDOT is beginning to experiment with the Ideal-CT test to become familiar with it and see where our current mixes are for the CT Index.

Florida DOT
Roadway density is now 40% of a contractor's pay factor (up from 35%). The ultimate goal is 45%. 5% was removed from the asphalt binder pay factor.

Indiana DOT
INDOT has gone to full implementation of Superpave 5 in 2020. We target 5% air voids in the design and in the field. We’ve achieved this by reducing design gyrations to 50. For a "no cost" specification change, we are seeing an average density of 94.4% (previously 93.2%).

Massachusetts DOT
MassDOT has just released an updated version of our Standard Specifications at https://www.mass.gov/lists/construction-specifications. This update standardizes our use of the Superpave mix design methodology and quality assurance requirements for HMA pavement construction.

Minnesota DOT
In 2020, we will let four to five projects using Superpave 5 following the INDOT procedure.

Montana DOT
We have no major changes planned. Previously we had indicated a move towards AASHTO M 332 MSCR for our binder specification, however that hasn't happened. We are still interested in moving that way but haven't made much progress for various internal reasons.

Oklahoma DOT
We’re adding ΔTc (-6), maximum REOB 5%, and maximum PPA 0.5% to our Binder Specification and implementing balanced mix design with Hamburg and Ideal CT (min. 80). We are writing a new split sample/referee special provision. Currently, we are conducting trials of mixes with dry process crumb rubber, highly-modified binders, and aramid fibers. We are exploring alternates to T-283. 0.5% antistrip agent in all HMA/WMA is an option. We are considering the possibility of going to only liquid additives for WMA.

Ontario MOT
We’ve been testing recovered asphalt cement for acceptance on a trial basis on a few jobs since 2019 and using the HMA regression method to increase asphalt content on a trial basis. After a decade of pause, the ministry is revisiting hot in-place recycling with a long list of candidate jobs. We’ve been conducting mix performance tests on production HMA on trial basis for a few jobs this year for informational purposes.

Tennessee DOT
We are moving forward with phase 2 of our intelligent compaction specification which adds data access for the inspector, weekly QC reporting, eliminates the separate pay item, and is planned to grow from roughly 35 projects the last couple years to approximately 50 this year.