Cement To The Rescue

摘要

When estimators for subcontractor ARS Inc. (Littleton, Colo.) bid the Front Range Community College parking lot reconstruction project in Westminster, Colo., they figured 8-percent Type C fly ash would meet the specified 160-psi strength requirement. The 30, 000-square-yard project called for pulverizing and stabilizing the parking lot's existing 4-inch asphalt surface and clay/sandy clay subgrade 12 inches deep, and then resurfacing with 4 inches of new asphalt. Designers considered stabilizing the subgrade with lime but choose fly ash because of a short construction deadline. Lime requires a mellowing and remixing process, where cement or fly ash can be processed the same day it is applied. "We fast-tracked it because we had to get it done before the students came back to school," said Skip DeFal-co, president of DeFalco Lee Construction, Longmont, Colo.