Transition points in steel fibre pull-out tests from magnesium phosphate and accelerated calcium aluminate binders

Abstract Results are reported on the pull-out characteristics of two distinct types of steel fibre from two different rapid strengthening matrices, magnesia phosphate and accelerated calcium aluminate. The procedure incorporated a novel method of identifying the force necessary to initiate whole fibre movement relative to the matrix, one of the key transition points in the force/displacement relationship. Significantly different force/displacement relationships were obtained with each fibre/matrix combination. The two types of fibre were of similar length and section diameter but one type was of regular circular cross-section and smooth surface finish whereas the other type was of irregular kidney shaped cross-section and rough surface finish. The two different matrices had similar strengths but were completely different chemically. The results are discussed in the context of transition points of fibre/matrix interaction.