Influence of organic admixtures on the rheological behaviour of cement pastes

• Published in: Cement and concrete research 2006-10, Vol.36 (10), p.1807-1813
• Main Authors: Phan, T.H., Chaouche, M., Moranville, M.
• Format: Article
• Language: English
• Subjects: Applied sciences; Buildings. Public works; Cement concrete constituents; Cement paste; Cements; Concretes. Mortars. Grouts; Exact sciences and technology; High-Range Water Reducers; Materials; Other special applications (sand concrete, roller compacted concrete, heavy concrete, architectural concrete, etc.); Properties and test methods; Properties of anhydrous and hydrated cement, test methods; Rheology; Viscosity Modifying Admixture
• ISSN: 0008-8846; 1873-3948
• DOI: 10.1016/j.cemconres.2006.05.028

The rheological properties of cementitious pastes used to proportion Self-Consolidating Concretes (SCC) have been examined, in particular, the influence of High range water reducing admixture (HRWRA) with that of Viscosity Modifying Admixtures (VMAs) have been compared. HRWRAs are known to have dispersing effects on the cement particles through steric and/or electrostatic repulsion, while the effects of VMAs are expected to stabilise the paste by increasing the viscosity of the aqueous solution. Both transient and steady state rheological behaviour of the cementitious pastes proportioned with different dosages of HWRA and VMA were considered. Experimental results show that the influence of VMAs on rheological properties is actually minor compared to that of HRWRAs. These results are discussed in the framework of rheology of concentrated suspensions.