Reconstruction of Urban Highways

Due to the ever increasing traffic volumes, the repair of concrete pavements has become one of the most difficult problems. One of the means to help resolve this problem is the use of a high early strength concrete. At the Department of Civil Engineering of the K.U.Leuven a research program has been executed to design a concrete mix that meets among other performances the following compressive strength requirements : after 2 days, the strength of concrete, stored at +7°C and determined on cores, drilled out of a concrete block, has to reach 40 N/mm2, after 7 days the strength must at least be equal to 50 N/mm 2 . From the experimental program, it follows that besides the use of a superplasticizer, ... a portion of the commonly used blast furnace slag cement in concrete for pavements has to be replaced by normal portland cement if concreting is executed at low ambient temperature conditions.