A unique experimental method for monitoring aggregate settlement in concrete

A unique experimental method for monitoring the settlement of aggregate in fresh concrete is introduced and demonstrated. Using nuclear medicine techn iques, real-time images of aggregate settlement due to vibration are obtain ed. These images are used to study the rheological properties of the vibrat ed concrete mix. The technique developed allows the experimental verificati on of a number of assumptions regarding the rheology of fresh concrete and the implications of the accepted rheological model of fresh concrete. Addit ionally, the effects of vibration on aggregate settlement are clearly shown , including effects resulting from the location of the vibrator and the siz e and density of the aggregate. (C) 2000 Elsevier Science Ltd. All rights r eserved.