Influence of Fly Ash on the Durability of the Surface Texture of Concrete for Road Construction

Project Number 270

Due to the constantly increasing traffic concrete roads are cumulatively built besides asphalt roads. However, due to the existing regulations of the Federal Institute for Road Construction (Bundesanstalt für Straßenbau, BAST) the use of fly ash in concretes for road construction is not permitted as up to now no practical proof of such concretes is existing about a sufficient resistance of the concrete surface to simultaneous exposure to frost-thaw and mechanical load.

Apart from the frost-thaw resistance of concrete in road construction with fly ash the research project shall examine especially the behaviour of the surface mortar with combined attack of abrasion, frost-thaw and chemical attack of salts. For these fundamental investigations two concretes with different water cement ratios are used. – To evaluate the improvement of the workability and formability by using fly ash with sands poor on fines a concrete with these sands will be produced. Concretes are examined, whose composition is varied by using two cements, two fly ashes and two sands. Until the examination the concrete samples are stored in four different climates at an age of 56 days.

Starting on September 1, 2005, and finishing on August 31, 2007, the project is carried out by the Chair of Building Material and Material Testing. The project is managed by Prof. Peter Schießl and is technically supervised by a working group of the Working Panel “Power Plant By-products”.