Key Insights
Quick Facts
- Name: I-10 Widening Project (Phase 2)
- Location: Baton Rouge, Louisiana
- Customer: Kiewit/Boh, AJV (Kiewit Infrastructure South Co. + Boh Bros. Construction Co., L.L.C.)
- Client: Louisiana Department of Transportation and Development (LADOTD)
- Size: 2.5 miles / $195.1 million
- Our Solution: Arcosa Lightweight supplied fine-graded lightweight aggregate from its Livingston, Alabama plant. The material was used to backfill critical retaining structures, reducing weight and improving constructability on poor subgrade.
- Why Lightweight Works: Arcosa’s lightweight aggregate offered a combination of low density and high internal friction angle, which reduced lateral earth pressure on retaining walls and minimized settlement, allowing for more efficient wall design and long-term performance.
Final Results
-
The lightweight backfill enabled engineers to reduce the size of the retaining wall cross-section while maintaining load-bearing performance. The use of Arcosa Lightweight helped control settlement and improved
Key Quote
— Jack Moore, P.E., Geotechnical Manager, Arcosa Lightweight
Context:
- Considerations: The site presented poor subgrade conditions and strict performance requirements for retaining structures. Lightweight aggregate was chosen to reduce the load on compressible soils and help meet compaction targets during construction.
- Lessons Learned: When working with marginal soils near critical infrastructure like abutments, lightweight aggregate can reduce pressure on retaining walls, limit settlement, and enable more efficient structural design.
See how Arcosa Lightweight materials perform in large-scale transportation projects with complex soil conditions and structural load demands.
Arcosa Lightweight Aids I-10 Widening to Alleviate Louisiana Traffic Bottleneck
Arcosa Lightweight Aggregate is playing a pivotal role in Phase 2 of the Louisiana Department of Transportation and Development’s I-10 widening project in Baton Rouge.
The $195.1 million construction effort is being delivered by Kiewit/Boh, AJV—a joint venture between Kiewit Infrastructure South Co. and Boh Bros. Construction Co., L.L.C., with James Construction Group, LLC serving as a major subcontractor.
The team brings decades of experience on complex interstate projects across Louisiana, including the reconstruction of 19 miles of the I-10/I-12 corridor over the past 20 years.
The current work widens a 2.5-mile section of I-10 from six to eight lanes and includes the installation of new sound reduction walls between the I-10/I-110 split and east of Acadian Thruway. Completion is expected by 2028, with traffic modeling predicting peak-hour travel time reductions between 2 and 18 percent.
Lightweight Aggregate: A Strategic Solution
Arcosa’s lightweight aggregate was selected for the project because of poor soil conditions and settlement-prone subgrade—specifically for backfilling on the abutment wall at I-10 westbound at Dalrymple Drive.
Jack Moore, P.E., geotechnical manager for Arcosa Lightweight, says lightweight aggregate fill is an effective way to reduce load demands on structures and bring added economy to challenging designs.
The material used for the I-10 project was produced at Arcosa’s Livingston, Alabama plant. Moore describes it as a blend that’s graded similar to coarse sand and behaves like a quarry backfill—“only it’s probably half or less the weight of that type of material,” he notes.
He points out that the soils underneath the widening area were far from ideal.
“They were settlement prone. That’s why they chose lightweight aggregate—to reduce the load on poor soils and manage settlement more effectively.”
Behind the bridge abutment, Moore explains, the cast-in-place wall retains the approach embankment. Because lightweight aggregate was used as backfill, the wall experienced less lateral earth pressure. “That allowed the team to reduce the cross-section of the retaining wall. It’s a good example of how the material’s low density and high internal friction angle can reduce the size of structural components.”
Proven Performance in Louisiana
Moore says this isn’t Arcosa’s first application of lightweight aggregate for LADOTD projects. “We’ve done several DOTD projects where lightweight aggregate fill was used behind mechanically stabilized earth structures,” he says.
One of the most notable examples is the Picardy Avenue Interchange in Baton Rouge, which opened in late 2006. The $50.6 million project created a new overpass and frontage roads connecting Bluebonnet Boulevard and Siegen Lane—improving access to the Mall of Louisiana and reducing congestion along that stretch of I-10. “It used modular block retaining walls for on-ramps and exit ramps,” Moore says.
He also points to another project from early 2025. “LA 531 was completed in the the summer of ’25 and was a similar application to the I-10 project profiled here,” he says. “That one also involved challenging soils and used lightweight aggregate to reduce settlement and structural load behind retaining walls.”
A Model for Other DOTs
Moore believes the I-10 project can serve as a reference point for other transportation departments tackling similar challenges. “They can see that lightweight aggregate fill is a viable solution for difficult site conditions,” he says.
“Today, most of the easy places to build on have already been developed. What remains are often widening projects with questionable soils. Lightweight aggregate helps reduce structural demand and adds cost efficiency to the project.”