State Route 52 Compaction Grouting

SR-52 in Kearny Mesa was completed in 1988.  It is San Diego County’s busiest east-west corridor with some 112,000 vehicles traveling in each direction on any given weekday.

The highway, which stretched about 5 miles east from Interstate 805 to Santo Road and cost about $33 million, was built in part over portions of the Miramar Landfill.

Before too long, the roadway started sinking. Maintenance crews went out and put down an overlay of asphalt, smoothing the roadway. Then parts of it sank as the ground underneath shifted again. That meant more asphalt. This has gone on every few years, costing taxpayers millions of dollars in repairs.

Now Caltrans is trying a different approach.

Condon-Johnson and Coffman Specialties, with help from GWCS, are drilling thousands of holes in the pavement, through all those layers of asphalt, and injecting columns of grout — a mixture of sand, water and cement — that will compact the underlying soil, fill in cavities and entomb some of the decomposing and ever-shifting trash.