Rheology of High-Performance Concrete: Effect of Ultrafine Particles

• Published in: Cement and concrete research 1998-05, Vol.28 (5), p.687-697
• Main Authors: Nehdi, M., Mindess, S., Aı̈tcin, P.-C.
• Format: Article
• Language: English
• Subjects: Applied sciences; Buildings. Public works; Concretes. Mortars. Grouts; Exact sciences and technology; General (composition, classification, performance, standards, patents, etc.); Materials
• ISSN: 0008-8846; 1873-3948
• DOI: 10.1016/S0008-8846(98)00022-2

The effect of ultrafine particles used as partial replacements for cement on the rheology of high-strength concrete (HSC) was investigated. Various proportions of 3 μm and 0.7 μm mean particle size limestone fillers, a finely ground silica, and silica fume were individually used as partial replacement for cement in 0.33 water/binder (w/b) ratio concrete mixtures. In addition, concrete mixtures were made with triple-blended composite cements containing different proportions of limestone filler and silica fume. A rheometer and the slump test were both used to measure the rheological properties at different ages, and the induced bleeding of the various concrete mixtures was investigated. An effort was made to explain why the production of HSC is made rheologically easier when ultrafine particles are added to the concrete mix. The effect of ultrafine particles on the superplasticizer requirement and the effect of time on the rheological characteristics of HSC were also examined. Likewise, the advantages of using triple-blended binders containing microfillers of various particle sizes were investigated.