Effects of poly(vinyl alcohol) on fiber cement interfaces. Part I: Bond stress-slip response

Abstract

This is the first part of a two-part article describing the effects of adding poly(vinyl alcohol) (PVA) to a cement based matrix to improve the bond at the fiber-matrix interface. Two types of fibers were used, steel and brass fibers (simulating brass-coated steel fibers) in a series of pull-out tests where the load versus global slip up to complete pull-out was recorded. The measured slips was that at the section where the fiber penetrates the matrix. The first article describes the mechanical effects of the addition of PVA, while the second article presents the microscopic observations. Correlation between the two studies is pointed out in the second part and conclusions are drawn. In particular, it is observed that the addition of PVA in the amount of 1.4% by weight of cement matrix leads to a significant improvement in the bond strength as well as in the frictional resistance, thus pull-out work, after the peak load.