Comparative study of the yield stress determination of cement pastes by different methods

Archive ouverte : Article de revue

Bala, Mokrane | Zentar, Rachid | Boustingorry, Pascal

Edité par HAL CCSD ; Springer Verlag

ACL. Different methods have been proposed inthe literature to determine the yield stress of cementgrouts. These methods may present wide differencesespecially for thixotropic materials such as cementpastes. In this paper, different mixtures of water–cement–superplasticizer were studied for various w/cratios and superplasticizer dosages. From shear tests ofthe mixtures in a rheometer, yield stress was deter-mined in different ways: by identification on theexperimental flow curve or by modelling flow curvethrough different rheological models. The conven-tional rheological models as Bingham model andHerschel–Bulkley model are not in agreement in themajority of the cases studied especially at low shearrates where thixotropy can be observed. In order toenhance the modelling in this area and allows toaccurately determine the yield stress, we compared theresults obtained through the conventional rheologicalmodels to that obtained by a thixotropy model. Fromthe obtained results, it turns out that the latter allows tobetter predict the behaviour of thixotropic cementgrouts and their yield stress.

• Contient
• Sujet
• Description
• Oeuvre