New TDOT Spec Book & TCAi Bot
Date postedMay 8, 2026
The new spec book became available on April 1, 2026. To assist members, TCA launched a members-only TCAi bot specifically programmed to quickly read and answer questions about this new specification book. Log in here to try out your question.
Key Note in New Spec Book:
Class DS vs. Class D: Class D remains an option, but only in limited instances and requires plan notes to justify its need. Class DS will now be the predominant mix and will be "fast tracked".
Key Updates from TCA Small Meeting Producer Feedback:
- PEM (Performance Engineered Mixes): There is a pending proposal to remove footnote 3 regarding freeze-thaw testing. Additionally, it has been proposed to allow PEM for any mix except Class DS.
- Material Substitutions: Provisions are already in place for fly ash and coarse aggregate substitutions during supply chain issues without requiring new trial batches, provided the material is on the approved list. substituted aggregates must be within .15 of the original Specific Gravity (SG).
- Cement Updates: Discussions regarding cement substitutions are ongoing. Please note that AASHTO has rejected the adoption of Type 1C cements, and TDOT will follow this lead. There is also discussion regarding reducing the tolerance from +/- 2.5 to 1 or 1.5.
Call for Case Studies
TDOT is seeking examples and case studies from commercial projects using Type 1C cement. If you have information to share, please let us know.
TDOT Audits
As a reminder, TDOT audits are generally triggered by low breaks, QCP changes, or significant turnover. These audits are intended to be collaborative rather than punitive.
Local Programs
TDOT is not serving as third-party testing for local programs and does not require daily reports. TDOT is no longer approving/reviewing mix designs for testing cylinders for local programs. They only need project batch reports to ensure work completion. Some city engineers use TDOT forms or write TDOT standards into local contracts, so they might be using the daily report, but TDOT does not need it. We are encouraging TCA members to clarify these issues with local municipalities to ensure everyone is on the same page.
TDOT welcomes your feedback and participation. TCA hosts 2-3 small group meetings annually to facilitate direct dialogue between producers and TDOT. These meetings directly impact discussions at Regional meetings. If you would like to be part of the TDOT Liason Committee, please let us know. We look forward to continuing our work together to build Tennessee with strength.
View slides from the recent TDOT regional meetings here.
Mark your calendar for the December TDOT Annual Meeting!
December 9, 2026 – Nashville Auditorium
9:30-11:00 AM Concrete Annual Meeting (for all Regions)
1:00 - 2:30 PM Aggregate Annual Meeting (for all Regions)