Title: Influence of Different Types of Silica Fume Having Varying Silica Content on the Microstructure and Properties of Concrete

Author(s): V. G. Batrakov, S. S. Kaprielov, and A. V. Sheinfeld

Publication: Symposium Paper

Volume: 132

Issue:

Appears on pages(s): 943-964

Keywords: admixtures; capillarity; cement pastes; diffusion; permeability; freeze-thaw durability; hydration; microstructure; porosity; silica fume; strength; water-reducing agents; Materials Research

DOI: 10.14359/2348

Date: 5/1/1992

Abstract:
Results of an investigation of cement paste structure, and strength, permeability, and frost resistance of concrete with admixtures of silica fume type are given. The admixtures are waste materials from metallic silicon, low-grade ferrosilicon, ferrosilicon chrome production, containing SiO2 in the amount of 92, 70, and 66 percent, and surface area of 25.0, 44.9, and 18.5 mý/g, respectively. The influence of the admixtures on the cement paste microstructure results in an increase of gel porosity volume, decrease of capillarity porosity, and in an increase of strength. Thus, concrete strength increases and its permeability decreases. Physical and chemical properties of the silica fume-type admixtures insignificantly affect gel pore volume, whereas they have significant influence on capillary porosity. An increased dosage of high-range water-reducing admixture (HRWR) is a beneficent factor in increasing hydration degree and gel porosity, decreasing capillary porosity volume, and, consequently, increasing strength. Concrete frost resistance with silica fume dosages up to 10 percent of cement mass is not lower than the reference concrete with the same amount of binder.