Single-fiber electromechanical pull-out testing and its application to studying the interface between steel fiber and cement

The experimental technique of single-fiber electromechanical pull-out testing was introduced and used to study the interface between steel fiber and cement. The technique involves measuring both the contact electrical resistivity between fiber and matrix and the shear bond strength in a fiber-matrix interface sample. Samples that are identically prepared differ in contact resistivity and bond strength, which correlate. The correlation allows determination of even small differences in bond strength due to differences in sample preparation conditions, such as fiber surface treatment, cement curing age and admixtures to the cement paste. It also gives information on the structure of the interface and allows the bond strength to be non-destructively determined by measuring the contact resistivity.