Title: Cement Paste Optimization for High Performance Concrete

Author(s): G. Giaccio and R. Zerbino

Publication: Symposium Paper

Volume: 207

Issue:

Appears on pages(s): 489-508

Keywords: cement type; flow time; high performance concrete; mineral additions; saturation dosage; superplasticizer

DOI: 10.14359/12408

Date: 10/7/2002

Abstract:
The characteristics of cement paste are very important for the workability, the mechanical properties and the durability of concrete, particularly in High Performance Concrete (HPC). Several problems of concrete such as slump loss, retardation in setting time or excessive heat of hydration, are directly related with some characteristics of the cement paste. This paper presents the results of a study made on cement pastes to select cementitious materials and chemical admixtures, and adjust mixture proportions before the concrete mixture design. Changes in the fluidity and the behavior of different super-plasticizers combined with cementitious materials including cements of different fineness, and different types or contents of mineral additions (calcareous fillers, natural pozzolans or silica fume) were comparatively studied by using the Marsh cone. It was found that the saturation point (defined as the dosage of superplasticizer over which the flow is not substantially modified) may change significantly with the type of superplasticizer, the fineness of the cementitious material and the incorporation of mineral additions (especially silica fume). Moreover, a quick and easy procedure was applied to analyze the behavior of different cement pastes regarding hydration process, setting time and heat development during the first ages.