Project Overview: REGEN Fiber Reinforces Iowa River Railroad Bridge 

In early 2025, Kraemer North America began construction on a new CRANDIC railroad bridge crossing the Iowa River in eastern Iowa, near Amana. This project is part of a strategic improvement effort for the more than 120-year-old rail line, which carries up to four trains a day, some weighing as much as 14,500 tons. Supporting that kind of heavy traffic requires durable, high-performance concrete, and REGEN Fiber played a central role in making that load-bearing possible.

Beyond the numbers and test results, we’ve also create a video that brings you onto the jobsite during the first pier cap pour on the Amana bridge project. concrete vet Dave Swanson walks through how the crew staged trucks, pumped a 4,000 PSI fiber-reinforced mix through dense rebar, and carefully managed head pressure to ensure proper consolidation.

You’ll see the concrete flow into heavily reinforced forms, watch how vibration locks the mix into place, and hear real-time feedback from the ready-mix producer and pump operators about how easy REGEN Fiber is to work with.

Project Overview 

To meet the structural demands, crews turned to fiber-reinforced concrete for bridge pier caps, using REGEN Fiber’s reinforcement fibers made from recycled wind turbine blades. Between March and May 2025, the project team completed three pier cap pours, each designed with a 4,000 PSI mix dosed at 5 lbs of fiber per cubic yard. In total, approximately 150 cubic yards of fiber-reinforced concrete were placed, delivering strength, pumpability, and long-term durability for this critical infrastructure.

The first pour in March placed 51 cubic yards of concrete supplied by Croell, Inc. and managed by general contractor Kraemer North America. The second pour in April added another 52 cubic yards, and the third pour in May contributed approximately 47 cubic yards, bringing the cumulative total for these projects to about 150 cubic yards reinforced with REGEN Fiber.

Fiber Performance 

Material performance on the jobsite exceeded expectations. Crews noted that the fibers dispersed evenly throughout the mix with no balling, and once placed, they were nearly invisible, even upon close inspection. Unlike other fibers that can leave a “hairy” or fuzzy surface finish, REGEN Fiber delivered a clean, smooth appearance. Pump operators and ready-mix producers also reported that the fibers moved seamlessly through equipment, even in cold spring conditions, ensuring reliable placement and consolidation.

Strength testing and field observations reinforced those impressions. In a preliminary test pour, 7-day cylinder break results came in 1,000 psi higher than typical, suggesting that REGEN Fiber contributes to early tensile and flexural strength gains in addition to long-term performance such as crack resistance. These results highlight how recycled fibers can serve as both a sustainable and functional solution in demanding heavy civil applications.

Project Wrap Up 

The CRANDIC Iowa River bridge project marks the first use of REGEN Fiber in a large-scale infrastructure setting, and the outcome speaks for itself: smooth finishes, predictable pumpability, clean placement, improved longevity, and a resilient product designed to last. By incorporating recycled wind turbine blades into critical concrete elements, the project not only strengthens a historic bridge but also supports the circular economy and reduces embodied carbon in public infrastructure.

With three pier caps now complete, the Amana Railroad Bridge is well on its way to serving rail traffic for another 100 years, with REGEN Fiber reinforcing every load.