Title: Performance Characteristics of Fiber Reinforced Condensed Silica Fume Concretes

Author(s): V. Ramakrishnan and V. Srinivasan

Publication: Symposium Paper

Volume: 79

Issue:

Appears on pages(s): 797-812

Keywords: compressive strength; fiber reinforced concretes; flexural strength; metal fibers; performance; plasticizers; silica; water-cement ratio; workability.

DOI: 10.14359/6726

Date: 5/1/1983

Abstract:
This paper presents the results of an investigation to determine the performance characteristics of fiber reinforced concretes containing condensed silica fume. The plastic concrete properties studied are slump, air content, unit weight, and Vebe-time. The hardened concrete properties investigated are compressive strength, flexural strength, toughness index, tensile strength, pulse velocity, static modulus of elasticity, and absorption co-efficient. These hardened concrete properties are compared at ages 3 to 90 days. A total of 17 mixes were made using type I cement, with the addition of condensed silica fume, steel fibers, and superplasticizers. Seven cement contents varying from 160 to 560 kg/m3 (270 to 945 lb/cu.yd.) were investigated with W/C ratios varying from 0.28 to 1. In all mixes condensed silica fume was added at 20 percent by weight of cement and steel fibers at 47.5 kg/m3 (80 lb/cu.yd.). The results indicate that the addition of condensed silica fume and steel fibers had reduced the workability consid-erably, however the workability can be restored with the addition of an appropriate amount of superplasticizer. In general the finishability of fiber reinforced concrete is improved with the addition of condensed silica fume. The unit weight of fiber reinforced condensed silica fume concrete is higher than the normal concrete. The addition of condensed silica fume is beneficial for fiber reinforced concretes with low cement content; it was shown that high strength fiber reinforced concretes could be made with low cement contents. The moisture absorption capacity of the con-crete is reduced with the addition of condensed silica fume. For the selected 20 percent addition of condensed silica fume, there is an optimum cement content and water content that considerably improves the performance characteristics of the steel fiber rein-forced concrete.