HIGHWAY NEEDS OF THE NATIONAL DEFENSE
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application of the same or even lesser loads. Some of the road effects of vehicular load are cumulative.
Applied loads may cause slight movements of the stone particles composing a so-called nonrigid road surface. If, by reason of the manner of load application, these movements tend to occur in the same directions under successive load applications, the condition of the road surface may rapidly deteriorate. In this manner corrugations are formed in gravel road surfaces.
Photo by Ansgar Johnson
Because this section of Idaho State Route 25 lacks adequate foundation, the surfacing breaks up regularly every spring. The mud has been scraped aside and replace by sandy soil as a temporary expedient. On such roads, the spring break-up means a seasonal restriction on permitted loads, yet 30 percent of the 2,300 vehicles using this road daily are trucks.
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