Indiana just told the cement industry it won’t accept any blended cement with more than 10% limestone.
That’s a first - and it’s not sitting well with the people who pushed Type IL cement in the first place.
For the first time, a state DOT pushed back on Type IL cement—and the industry fired back. Indiana’s Department of Transportation says it’s protecting performance after bridge decks started scaling. The American Cement Association says the DOT’s new limits are unnecessary, confusing, and unscientific. So, who’s right—and what does it mean for the rest of the country’s concrete?
What You’ll Learn
• Why INDOT limited Type IL limestone content to 10%
• The ACA’s objections — and what’s left unsaid
• How PCA’s 2021 carbon-neutrality roadmap and the federal Buy Clean program accelerated the switch to Type IL
• Why the “one-to-one replacement” claim may have been oversold
• How variable limestone content (≈7.6–12.4%) affects consistency and performance
• Why admixtures and curing aren’t substitutes for good practice
• What INDOT’s maintenance and inspection programs get right
• Why other DOTs may follow Indiana’s lead next
Chapters
00:00 – Introduction & ACA Briefing Overview
01:00 – INDOT’s 10% Limit and Industry Response
04:00 – How Type IL Cement Took Over the Market
07:30 – PCA Roadmap & Federal Buy Clean Pressure
10:30 – Complacency and the One-to-One Myth
14:00 – What Really Drove the 2021–2023 Flip
18:00 – Cement Chemistry and QC in the Field
22:00 – The Variability Problem: 7.6% vs 12.4% Limestone
26:30 – Are Admixtures and Curing the Real Culprits?
30:00 – INDOT’s Data-Driven Maintenance Approach
32:00 – Why Other States Are Watching Closely
Guest Info
Dr. Jon Belkowitz – Chief Technical Officer, Intelligent Concrete
Email: jon@intelligent-concrete.com
Website: https://www.intelligent-concrete.com
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Podcast Partners
Intelligent Concrete
At Intelligent Concrete, we combine lab precision with field expertise to help you understand what your concrete is telling you. Our services include mix troubleshooting, forensic and petrographic testing, performance-based specification and admixture development, and training for engineers, contractors, and producers. Whether you’re chasing consistency, durability, or answers after a failure, Intelligent Concrete delivers the data and insight to solve problems and improve performance.
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Credits
Produced by Jodi Tandett & Concrete Logic Media
Music by Mike Dunton — https://www.mdunton.com
Connectivity
Host: Seth Tandett
Concrete Visionary | Business Development at Baker Construction | Host of the #1 Concrete Podcast
LinkedIn: https://www.linkedin.com/in/sethtandett/
YouTube: https://www.youtube.com/@concretelogicpodcast
Website: https://www.concretelogicpodcast.com
If you learned something new, share this episode with your team and help more engineers and builders think logically about concrete.
Until next time, let’s keep it concrete!
Reference Links
• ACA Briefing: “Portland-Limestone Cement Limits in Indiana Department of Transportation Specifications” (October 2025 Update) — https://tinyurl.com/TypeIL
• INDOT Recurring Special Provision 901-M-069 (Effective December 1, 2025): https://www.in.gov/dot/div/contracts/standards/rsp/sep25/900/901-M-069%20251201.pdf
• INDOT Testing Memos Referenced in ACA Briefing:
• 21-05 • 22-02 • 23-01 • 24-03 • 25-02 (Available at https://www.in.gov/indot/doing-business-with-indot/contractorsconstruction/division-of-materials-and-tests/current-testing-memos/)
