Title: Mix design and the effect of silica fume and steel fiber on rheological and mechanical properties of mortars

Author(s): Siaw Foon Lee, Xiao Hui Wang, Stefan Jacobsen

Publication: NCR

Volume: 41

Issue: 3

Appears on pages(s): 33-50

Keywords: Mortar, silica fume, steel fiber, rheological, mechanical properties, air-void content.

DOI:

Date: 6/15/2010

Abstract:
Mortars with water and binder ratio (w/b) 0.3 and 0.5, with and without 10% silica fume by cement weight and with 0, 0.3 and 1 vol% steel fibers were made to study the effect of silica fume and steel fiber on rheological and mechanical properties. Slump, yield stress and plastic viscosity of fresh mortars were measured. Three-point bending and compressive tests were performed on the mortars after 28-day curing. It was found that silica fume improved the cohesiveness of fresh mortars, increased the compressive strength but showed no obvious effect on the bending strength for both w/b either with or without 0.3 vol% steel fiber. The inclusion of 0.3 vol% steel fiber greatly affected the workability of fresh mortars with w/b 0.3 without silica fume compared to that with silica fume, and gave no effect on mortars with w/b 0.5. 10% silica fume and 0.3 vol% steel fiber increased the air-void content slightly. However, plots of strength as function of air void content over a small range did not show that air void gave a general reduction of strength.