Koss Construction Company’s asphalt and two concrete paving divisions teamed up in the summer of 2011 to complete a much-needed upgrade on 18 miles of US-50 West of Cimarron in Gray County, KS. Originally a 30’ roadway consisting of two 12’ lanes, 3’ shoulders and limited by-pass and turn lanes, Koss converted this corridor into a “super-two” facility, added two, one-mile long passing lanes with shoulders and constructed six new by-pass and turn lanes, including a center turn lane at Ingalls, KS. Work on the project began shortly after award of the contract in the spring of 2010. Subcontractors moved over 330,000 cubic yards of excavation and borrow while extending over 80 drainage structures more than 1300 feet. Let by the Kansas Department of Transportation with multiple surfacing options, the base bid called for nominal milling to correct cross slope and a 2” HMA overlay. All newly constructed widenings and shoulders called for 6” of fly ash stabilization. Koss utilized product alternatives that included 9” NRDJ PCC paving on a 4” cement treated base for the new driving surfaces. The adjacent 6” PCC shoulders were placed on a 7” granular base. All PCC paving was finished 2” above the milled surface to accept the new overlay. The existing shoulder improvements consisted of a relatively new product called roller compacted concrete (RCC), a plant mixed “zero slump” concrete placed and compacted to grade just like asphalt and in this case, to the top of the milled surface. Koss faced several challenges on the project with the biggest being traffic. All work was performed under traffic without closing any side roads or any portion of the highway with the use flaggers, pilot cars, lane shifts and barrier wall.