A highway contractor has opened a cut in fine silty sand (SM).Because of the cut location and lack of drainage, surface water hasdrained into the cut, leaving the material very wet. Rubber-tiredscrapers are hauling material from the cut to an adjacent fill. Thematerial is being placed in the fill in 20 to 25cm lifts andcompacted by heavy sheep foot roller towed by a crawler tractor. Itis apparent that the specified compaction (95% of standard AASHTOdensity) is not being attained. The sheep foot roller not “walkingout and scraper tires are causing the compaction problem? Whatwould you suggest to the constructor to improve the compactionprocess? Ideally, concrete should be poured at temperatures between16°C and 38°C.
