Northwest Arterial reconstruction Dubuque with MIRAFI

The three-mile Northwest Arterial in Dubuque, Iowa, carries over 25,000 vehicles per day and serves critical nearby infrastructure, including two hospitals, two fire stations, and nine schools, earning three prestigious awards from the Iowa Asphalt Paving Association for its excellence in construction and design.

Overview

The Northwest Arterial is a critical transportation corridor in Dubuque, Iowa, serving as a primary route for commuters, emergency services, and school transportation. With its high traffic volume and proximity to essential infrastructure, maintaining the roadway’s integrity is vital for public safety and mobility. The City of Dubuque launched a major reconstruction initiative to rehabilitate the corridor while adhering to a constrained budget, supported by a combination of local and federal grants.

Challenge

During excavation, crews encountered widespread subgrade instability, with several sections exhibiting moisture-sensitive soils and poor load-bearing capacity. Traditional remediation techniques, such as scarifying and drying, were attempted but failed to deliver consistent results. Full-depth subgrade replacement was evaluated but quickly ruled out due to its high cost and potential derailment of the project's timeline. With the clock ticking and traffic detours already in place, the City urgently needed a reliable, cost-effective solution that could be implemented quickly and performed under demanding conditions.

Solution

Solmax, in partnership with Quick Supply, collaborated closely with the City’s engineering team to develop a geosynthetic-based stabilization strategy. Leveraging InfraSolve®, Solmax’s advanced pavement design software, the team modeled several design scenarios using:

• MIRAFI® RS380i

• MIRAFI RS580i

• MIRAFI H₂Ri

Each option was tailored to specific subgrade conditions, enabling the City to apply the most efficient solution to each segment of the corridor. This targeted approach minimized material waste and maximized performance. After thorough evaluation, MIRAFI RS580i was selected for its:

• High tensile modulus for superior reinforcement

• Excellent separation and stabilization characteristics

• Proven field performance and ease of installation

• Compatibility with InfraSolve for predictive performance modeling

The material was delivered promptly, allowing construction to resume without delay and avoiding costly schedule overruns.

Results

The deployment of MIRAFI RS580i successfully stabilized the problematic subgrade areas, allowing paving operations to proceed smoothly. An engineer with the City of Dubuque praised the installation saying, "we were very impressed with the performance of the geosynthetic and had no further subgrade stability issues going forward.” The project was completed on time and within budget, earning widespread recognition, including several awards from the Asphalt Paving Association of Iowa (APAI):

• 2023 Award for Quality Paving – New Construction

• 2023 Perpetual Paving Award

• 2023 Robert M. Nady Award of Excellence

The Northwest Arterial Reconstruction Project exemplifies how innovative engineering, strategic partnerships, and advanced materials can overcome complex infrastructure challenges. By integrating geosynthetics and performance-based design tools, the City of Dubuque delivered a resilient, high-quality roadway that will support the community’s needs for decades to come-without compromising on cost or schedule.