Portland cement based fast-setting concrete demonstration, district 07, Los Angeles County

mmpPDFResearch PaperPortland cementHigh early strength cementMaterials testsCalifornia. Dept. of TransportationCalifornia. Dept. of TransportationNTL-HIGHWAY/ROAD TRANSPORTATION-MaterialsUS Transportation CollectionThe California Department of Transportation currently uses fast-setting concrete to accommodate short working windows. The current special provision for fast-setting concrete requires that the concrete reach a flexural strength of 2.8 MPa (400 psi) before opening to traffic. This special provision is a performance specification that allows the contractor to be creative with materials as long as the specified strength is attained. Development of a portland cement based mix that cam be placed and opened to traffic in four to six hours has been elusive. In a continuing effort to demonstrate the effectiveness of fast-setting concrete using non-propriety cements, Translab and Industry have evaluated several portland cement based concrete mixes. MasterBuilders, Inc., appears to have developed an admixture system that meets or exceeds the requirements of the special provisions. With the assistance of Teichert Ready Mix, National Ready Mix, and Chumo Construction, MasterBuilders provided Translab the opportunity to evaluate this mixture by placing three different slabs. This blend of chemical admixtures and cement was found to be user-friendly by both the concrete producers and the construction crews placing and finishing slabs, and provided ample for delivery trucks to be washed out. 2 Tables, 5 figures, 13 p