The Cohasset Road Widening Project was a transformative endeavor to enhance transportation infrastructure and support economic development in the City of Chico. Spanning approximately 2.3 miles, the project converted a two-lane road that had a history of severe vehicle accidents into a four-lane thoroughfare, improving the safety of the roadway significantly. With the better accessibility to the City of Chico, the expanded highway also works to reduce congestion and connectivity issues faced by businesses, residents, and the wider community.

Recognizing the success and the impact of the work, the Northern California / Western Nevada Chapter of the American Concrete Institute (ACI) presented the project with the ACI Award for Excellence in Concrete Construction – Flatwork last year at the chapter’s annual gala.

Along with new concrete pavement, improvements included enhanced intersection lighting for safety and xeriscape landscaping features.

The project covered the section of Cohasset Road between the Sycamore Creek Bridge and Ryan Avenue, building four new 12-foot lanes and eight-foot shoulders. Street lighting, right and left turn pockets, and enhanced storm drainage improvements were installed at intersections to enhance traffic flow and safety.

Vanguard Construction was the contractor on the Cohasset Road Project and performed all of the work.

The scope of work included full roadway excavation, earthwork, and the placement of aggregate base and Portland cement concrete (PCC) paving. Underground work included the installation of sewer main extensions to better serve existing industrial and commercial properties along the corridor. Storm drainage improvements, including roadside bio-swale ditches, culverts, and detention basins, are now mitigating erosion and enhancing water management along the roadway.

Vanguard’s nearby batch plant expedited the schedule thanks to swift material delivery.

The concrete was produced in Vanguard’s mobile batch plant, set up a half mile from the project alignment. This assured great control of the material thanks to minimal transport time and the use of dump trucks versus ready mix trucks.

The reflectivity of the new concrete pavement keeps it cooler than asphalt. Side-by-side summer temperatures reading were 99.5 degrees for concrete pavement and 121.8 degrees for asphalt, a 22.3-degree difference!

Vanguard paved with a concrete mix developed with an aggregate gradation that met the “Tarantula Curve” limits, helping assure the mix would respond well to the vibrations of their Gomaco paver right out of the gate. The mix also met early strengths for maturity opening, which facilitated construction traffic and early traffic accessibility.

Pan Pacific cement was used in the mix, as well as Nevada Cement Natural Pozzolan, which helped with Alkali Silica Reactivity concerns, and furthered the sustainability benefits. The Vanguard crew indicated that this SCM – Supplementary Cementitious Material – helped with the finishability of the concrete pavement.

In addition to roadway improvements, the project relocated the existing Class I bike trail

10 feet to the west of its current location and expanded it to a width of eight feet, with two-foot-wide shoulders. Connected to the Chico’s extensive bicycle network, two-wheeled commuters can now easily and safely travel to the employment centers at the Chico Regional Airport from surrounding residential neighborhoods, saving a little more CO2 from going into the atmosphere.

Along with Vanguard performing the construction work, the City of Chico was the owner and managing agency, Mark Thomas & Company designed the project, and PSOMAS served as the construction manager.

Big thanks and a tip of the hard hat go out to Brendan Ottoboni, Director of Public Works – Engineering, City of Chico, for most of the content for this story. And to Clay Slocum, Director of Engineering, California Nevada Cement Association, for his kind assistance.