Estimation of the content of ground granulated blast furnace slag and different pozzolanas in hardened concrete

Methods for estimating the content of ground granulated blast furnace slag (GGBFS), fly ash and other pozzolanas in hardened concrete were investigated including a selective dissolution procedure, a method based on scanning electron microscopy (SEM) combined with image analysis and a XRF method. The results reveal that the content of GGBFS in concrete can be estimated with all methods. The accuracy of the selective dissolution method can be increased by consideration of the dissolution behaviour of the respective aggregate. SEM investigations combined with image analysis additionally enable the estimation of the content of pozzolanas like fly ash or calcined clay.