Blog

What’s New with Concrete Specs at Caltrans?

By Charley Rea, VP of Policy and Communications

A few quick updates on the workings of the Concrete Task Group of the Pavement and Materials Partnering Committee (PMPC), the working group of Caltrans and materials producers to update specifications and test methods.

How to approve new criteria to evaluate alkali-silica reactivity (ASR) in supplementary cementitious materials (SCM). This will determine how SCMs are approved for the Authorized Materials List (AML). Getting the ASR criteria established is important for approving new sources of SCMs. One focal point has been the availability of harvested fly ash, for which Caltrans has been limited to approving on a project-by-project basis. At this point, it is expected the criteria for new SCM materials will be completed by the end of the summer. While the changes may not be in the specifications until 2026, it is expected a Construction Procedure Directive (CPD) will be issued to allow their immediate use. 

These are three other changes that may be coming soon: 

Completion of a specification change to allow a fixed value of compressive strength for acceptance of concrete pavement strength. The changes to Section 40 are expected to be done later this summer, and should appear in the 2026 standard specifications.

Also, being worked on are changes to 1) better define how to investigate low strength test results and 2) allow automated technology for ad mixtures at concrete plants. These relatively narrow changes may come in the form of a Decision Document that can be implemented readily.

Finally, Concrete producers should also be aware that there are a series of specification changes to Sections 51 and 90 that will come out in the Fall 2025 edition of the specifications. A summary is provided in this document.