The Indiana Department of Transportation (INDOT) and state lawmakers are actively addressing performance and durability concerns impacting concrete pavements across Indiana’s road and bridge networks writes Kara Kenney for WRTV. Issues such as premature cracking, surface scaling, and the premature breakdown of friction-enhancing grooves, or tines, have been observed in relatively new projects completed in 2023 and 2024. While INDOT emphasizes that these observations do not pose an immediate safety risk, with safety being their top priority, they confirm the challenges are primarily related to the expected lifespan and durability of the infrastructure. Documents from the agency, including a memo from October 2024, have cited “durability concerns” with recently placed concrete bridge components, signaling a statewide effort to understand and rectify these early-onset challenges.
The core of the investigation appears to focus on the increased use of Type 1L (Portland Limestone) cement, which INDOT began allowing on projects in 2015 and which became the primary cement type used in the state by 2022. This newer cement is widely valued for its environmental benefits, specifically its ability to reduce CO2 emissions compared to traditional cement. However, national experts have noted that Type 1L is generally softer and more porous. Experts consulted on the issue suggest that proper training is crucial, noting the difference in material composition means contractors need specific guidance on how to use the newer cement effectively on job sites to ensure optimal performance. The Indiana Ready Mix Concrete Association (IRMCA) has expressed full commitment to working with INDOT and fully supports an independent, third-party investigation to determine the root cause of the performance issues.
Responding proactively, INDOT is collaborating with the industry to look at improved training, sharing of information regarding Type 1L, and adjusting best practices. A significant step taken by the agency was the implementation of a 10% cap on limestone content in cement for state contracts, effective September 10. While INDOT views this as a positive step toward a solution, they acknowledge that the investigation into the complexities of Type 1L cement and construction methods is ongoing. Legislators have also highlighted the urgency of the matter, with eleven lawmakers sending a letter to the Legislative Council in May 2025 citing the “increasing performance failures in concrete pavements” and warning of accelerated maintenance schedules and unexpected costs for infrastructure designed for a multi-decade service life.
Despite the challenges being experienced with these newer mixes, concrete remains a fundamental component of resilient infrastructure, valued for its strength and longevity, as evidenced by its use in home foundations and major commercial projects. INDOT’s current research, which includes third-party testing, is aimed at ensuring that the state can continue to utilize the environmental benefits of Type 1L cement while guaranteeing the expected multi-decade service life for its essential roadways and bridges. The commitment from both the state and industry partners highlights a unified effort to solve the issue, ensure quality control, and maintain the integrity of Indiana’s transportation network for the traveling public.