County engineer reports concrete 'blow ups,' DOT coordination and Pleasant Grove progress

County Engineer Brian Carter told supervisors on July 7 that recent extreme heat and humidity contributed to several "concrete blow ups" on county roads, requiring overtime repairs, temporary signage and in some cases full‑depth patches.

"The only time it seems that concrete blows up is when it's somewhere between 90 and a 100 degrees and sky high humidity … and somewhere between 04:00 in the afternoon and 06:00 in the afternoon," Carter said, describing the conditions that trigger repeated pavement failures. He said crews placed signage to keep traffic slow to avoid full road closures and that repeated failures can exhaust available warning signs.

Carter said county staff are working toward an agreement with the Iowa Department of Transportation for typical agreements on sections of road being reconstructed along Route 61 northward to the county line, and that he expects a formal agreement to be placed on a future agenda this summer or early fall.

On the Pleasant Grove project he said initial rock base has been placed in one lane, progress slowed by recent rain, and crews are working sequentially to get base rock in place to avoid washouts. He also noted staff continue to pursue a survey of a public health property discussed previously and will follow up with consultants and city feedback before finalizing easements and layout.

Carter suggested a possible construction tour for supervisors when mainline paving is scheduled so board members can observe the operation in the field.