VALENTINE,Neb. (AP) – Pavement work is expected to disrupt traffic on U.S. Highway 83 near Valentine in northern Nebraska.  The Nebraska Roads Department says the work will begin Monday.  New pavement will be laid as base work is completed on a nearly 8 1/2-mile stretch from north of Valentine to the South Dakota state line.  The department says a pilot car and flaggers will be used to guide motorists through the construction.  The nearly $2.8 million project is scheduled to be finished this fall.