Title: Interfacial properties of steel fiber at mortars with different water and binder ratios: backscattered electron image analysis and nanoindentation testing

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

Publication: NCR

Volume: 42

Issue: 8

Appears on pages(s): 127-142

Keywords: Steel fiber-reinforced mortar, Backscattered electron image analysis, Nanoindentation, Interfacial transition zone.

DOI:

Date: 12/15/2010

Abstract:
Backscattered electron image analysis (BSE-IA) and nanoindentation were adopted to study the properties in the interfacial transition zone (ITZ) of steel fiber with a diameter of 0.16 mm. Mortars with three different water and binder (w/b) ratios were made. A good sample preparation procedure that gave a surface roughness of less than 1 μm was used. It was found that the thickness of ITZ of steel fiber was 30 μm. BSE-IA and nanoindentation testing revealed that mortars with w/b 0.3 had less area % of porosity and higher hardness and elastic modulus at the ITZ than mortars with w/b 0.5. BSE-IA also showed that silica fume 10 % by cement weight did not densify the porosity in the ITZ as expected. This was in line with nanoindentation result which showed that mortar with 0 % silica fume had better interfacial bonding than mortar with 10 % silica fume for w/b 0.3.