Standard Specifications of Middle Performance Concrete for Highway Tunnels

Abstract

Expressway companies in Japan have developed middle performance concrete that uses stone powder and coal ash and compiled Construction Management Guidelines for it in August 2008. Stone powder and coal ash, however, do not satisfy the standard specifications for middle performance concrete owing to various factors including current distribution conditions and plant facility limitations. We, therefore, conducted studies to verify the properties and quality of middle performance concrete, using an admixture whose quality and availability do not depend on local conditions and reached a conclusion that such concrete is applicable as a standard material for highway tunnels. Furthermore, to evaluate the long-term durability of middle performance concrete, we also carried out a follow-up study of the middle performance concrete that uses coal ash and limestone fines, after construction, and found the concrete to be of greater density and higher quality than ordinary lining concrete.