Interstate 8 in California covers 287 miles, running from San Diego to the Arizona border. The section of the interstate in the I-8 Pavement Replacement and Road Improvements Project is located between Viejas Creek in the Town of Alpine and the Pine Valley Bridge, to the east, in the heart of Cleveland National Forest. This section of roadway was constructed in the late 1960s and early 1970s.

Improving the Roadway with CRCP
This 10-mile stretch of Interstate 8 has a traffic volume of approximately 100,500 vehicles per day. Over the 50+ years since the road was paved, that amounts to a lot of wear, especially from 18-wheelers. To improve the pavement in this section of I-8, Continuously Reinforced Concrete Pavement (CRCP) was selected to replace the existing pavement. CRCP provides a superior, long-lasting roadway that reduces the need for repair and replacement in the future, thereby reducing impacts on the traveling public and exposure to traffic by the construction crews.

If you’re not familiar with CRCP, Continuously Reinforced Concrete Pavement (CRCP) is constructed with steel reinforcing bars placed within the concrete along the entire length of the pavement. CRCP naturally forms tight transverse cracks to transfer loads evenly.

With the old pavement removed, the outer lane and shoulder are prepared for the new base.

Extending Service Life
The result is a continuous, smooth-riding surface capable of withstanding the heaviest traffic loads and the most adverse environmental conditions. The lifespan for CRCP pavement may be up to 70 years, far exceeding that of existing road surfaces.

Safety
Safety for the traveling public, including safety and protection for highway workers, is priority number one for Caltrans and measures have been taken to ensure that. Throughout the project, construction has taken place behind reinforced concrete barriers, also known as K-rail, which serves to protect construction crews and also expedite the construction schedule. The speed limit in the construction work zone speed limit has been reduced to 55 MPH, and advanced warning traffic signs have been in place for the duration of the project to notify drivers well before they reach the project site.

K-rail safely separates the Granite crew at work from the active traffic lanes.

Caltrans Project Manager Malikyar Abdul detailed the importance of Interstate 8 to the State of California. “I-8 is the primary route used by Imperial County agricultural producers to transport their products to San Diego County areas, provides access to suppliers of the agricultural support industries, and connects distribution centers and consumers between the San Diego region and the Mexicali/Calexico region and beyond. Imperial County’s agricultural products include cotton, sugar, beets, alfalfa, and table vegetables such as asparagus, broccoli, and carrots. Most of these perishable products are transported during seasonal peak periods as crops are harvested.”

Optimized aggregate and sand piles lead to the onsite Granite batch plant.

Abdul continued. “Interstate 8 has been designated by Caltrans District 11 as a State Highway impacted by the North American Free Trade Agreement (NAFTA). The portion of I-8 from I-5 to the Arizona border is a designed route in the National Network for Surface Transportation Assistance Act (STAA) for trucks. The segment of I-8 from Interstate 15 in San Diego County to the future junction with State Route 7 east of El Centro is included in the Statewide List of Lifeline Routes. A lifeline route is a route that is deemed so critical to emergency response/lifesaving services of a region and the state that it must remain open immediately following a major earthquake, along with detour and emergency response activities.”

The erected Granite batch plant ready for operation.

Phased Approach
The I-8 Pavement Replacement and Road Improvements Project was split into five stages, beginning in September 2022, and concluding in March 2024.

Stage 1
Stage 1 included improvements of the Sweetwater, Japatul Valley, and Horsethief Bridges, along with approach and departure slabs for these bridges. Additional work included individual slab replacements and 1,000 feet of CRCP on each side of the bridges. Completed in December 2022, motorists have now been experiencing an improvement in ride quality in this section over the past two years.

Stage 2
The scope of work in Stage 2 included 3.5 miles of new CRCP in the Number 3 lane and the outside shoulder, the asphalt pavement in lanes 1 and 2 on Horse Thief Bridge was removed and replaced with CRCP, and new CRCP was placed in Lane 2. Stage 2 was completed in December 2023.

Stage 3
In July of 2023, Stage 3 featured the removal of the asphalt in Lane 2 and new CRCP placement in Lanes 2 and 3. The asphalt was also removed from Lanes 1 and 2 on the Las Blancas Bridge and replaced with CRCP. Stage 3 work concluded in December 2023.

The epoxy-coated CRCP rebar is given a final check before the placer/spreader and slipform paver roll in.

Stage 4
Currently underway, the scope of work in this stage is focused primarily on the remaining bridge rehabilitation projects on the three structures, some old CRCP replacement, and new shoulder paving.

Granite’s Gomaco RTP-500 Rubber-Tracked Placer smoothly negotiates the uneven adjacent terrain to get the job done.

Stage 4 proved to be especially difficult due to the landscape moving through the mountains. This stage was the replacement of lane 2 and lane 3, and installation of an asphalt shoulder. The mountainous terrain did not allow for a typical haul road and placement with a rubber track placer (RTP). The concrete paver and placer/spreader had to be specifically modified to allow for paving through such tight conditions. The traffic configuration did not allow for any lane closures either.

Working through the night in the desert environment, paving continues at the Highway 79 on-ramp.

There was also a considerable amount of work to build the necessary track grade for both machines. In some areas, there were slopes greater than 300’ to the bottom of the valley. Granite had to ensure that the track grade and haul road were strong enough to support loaded trucks while they were moving to the paving spread. However, a portion of the paving was performed with the RTP, as the terrain allowed for haul roads to be pioneered and installed for conventional paving. Targeted completion for this work is this winter.

Pictured here in Stage 4, Phase 2 is the new 14-foot-wide slipformed slab.

Stage 5
Following that in the winter of this year, final striping and clean-up will take place in the Stage 5 work that concludes the project.

Working safely behind K-rail, Granite gained a lot of efficiency paving 26 feet wide with their Wirtgen slipform paver.

Funding
The extensive project, which began construction in June 2022, is scheduled to be complete in winter 2024/2025. The total project cost is $57.6 million, including support and construction costs. This is a State Highway Operation and Protection Program (SHOPP) funded project; SHOPP project funding is a mixture of Federal and State funds, including the Road Maintenance and Rehabilitation Account created by Senate Bill 1 (SB 1), California’s Road Repair and Accountability Act of 2017.