Title:
Strength and Freezing-and-Thawing Resistance of Concrete Incorporating Condensed Silica Fume
Author(s):
Takeshi Yamato, Yukio Emoto, and Masashi Soeda
Publication:
Symposium Paper
Volume:
91
Issue:
Appears on pages(s):
1095-1118
Keywords:
air entrainment; compressive strength; concretes; drying
shrinkage; flexural strength; freeze-thaw durability; mortars
(material); permeability; porosity; pozzolans; silica.
DOI:
10.14359/10114
Date:
2/1/1986
Abstract:
This report gives results of laboratory investigations to determine the strength characteristics and the pore size distributions of mortar and concrete incorporating condensed silica fume from a Japanese sourse. This report also gives results of the shrinkage, permeability and freezing and thawing resistance of concrete incorporating silica fume. A series of mortar mixes was made with a water-to-cement plus silica fume ratio of 0.65, and the percentage of silica fume used as partial replacements for normal portland cement of 0, 5, 1O, 20 and 30 % by weight. A total of twenty three concrete mixes were made with the water-to-cement plus silica fume ratio(W/C+S) ranging from 0.25 to 0.55, and the percentage of silica fume used as partial replacement for cement of 0, 5, 10, 20 and 30 % by weight. All mixes were not air-entrained except mix with the W/C+S of 0.55 which was air-entrained. A superplasticizer was used for all the mixes incorporating condensed silica fume. Condensed silica fume improved the compressive strength of the mortar and the concrete at 28 and 91 days and the impermeability of the concrete. The drying shrinkage of the condensed silica fume concrete was comparable to that of the control concrete without silica fume. Non air-entrained silica fume concretes with the W/C+S of0.35, 0.45, and 0.55 showed low durability factors, although the air-entrained concrete with a W/C+S of 0.25 performed satisfactorily to the repeated cycles of freezing and thawing. The air-entrained concrete incorporating 20 and 30 % silica fume with a W/C+S of 0.55 showed very poor durability as compared with the control concrete.