Adhesion of Polypropylene Fiber to Cement Matrix

In this research, the adhesion of polypropylene (PP) fibers to cementitious matrix has been investigated and the chemical bonding and mechanical interlocking between PP fiber and hardened cement paste has been studied. Furthermore, thermodynamic work of adhesion and loss-function (dissipation energy) has been calculated in the PP-cement matrix model system. To investigate the work of adhesion, the pull-out test has been used. Also, the surface free energy and contact angle of the PP monofilaments and cement matrix have been measured using a tensiometer and the fiber-cement interfacial interactions and thermodynamic work of adhesion and loss-function were calculated. Scanning electron microscopy (SEM) analysis was used to study the fiber-cement matrix interfacial transition zone (ITZ). The results showed that the application of theories of polymer-polymer adhesion in fiber-cement matrix systems was feasible. To verify the accuracy of the method, the adhesion of two other fibers (nylon 6,6 and acrylic polymer) was studied. (C) Koninklijke Brill NV, Leiden, 2012