Bøger af Stefan Kubens

Dispersing admixtures play an important role in today¿s concretetechnology. Around eight billion cubic metres of concrete aremade each year and most of it contains dispersing admixtures.These chemical compounds, added at low dosages during concretemixing, make fresh concrete more liquid and improve its workability.A precise way to determine the workability of concrete is to measureits rheological values yield stress and plastic viscosity. Fromready mixed concrete plants and concrete element plants it is knownthat rheological values of mortar and concrete can sometimes varywhen a new cement batch (i.e. a new production date) is used. Theaim of this study is threefold. Firstly, to measure and evaluate theeffect of variations during routine cement production on the rheologyof mortar and concrete. Secondly, to identify the constituentsin cement which lead to fl uctuations in rheology. Thirdly, to quantifythe changes in rheology due to variations in cement properties.These questions are essential for cement and concrete producersto guarantee a homogeneous concrete production, but also for thescientifi c community to reach a deeper understanding of cementadmixtureinteractions.