AN IMPROVEMENT OF BOND STRENGTH BETWEEN FERROCEMENT SKIN AND CORE MATERIAL OF FERROCEMENT FORM

Abstract

Ferrocement Form supporting structural elements (Beams) is subjected to flexural forces due to the beam’s self weight. The bond between the Ferrocement form skin and the core material results in the mobilization of the tensile bond strength at the interface which is a plane bond. The study attempted to improve the bond strength by proposing an interlock bond at the interface. This was achieved by characterizing the bond strength according to the material strength used as the Ferocement skin and that of the core material. Experimentation was conducted in the Laboratory using normal Mortar, Granite mortar and self-compacting concrete- mortar interfaces as replicas to simulate Ferrocement Forms with in-filled/ core materials. Cubes were cast from the mixes of these materials and their compressive strength determined. Similarly, Cylinders were cast from the mixes of these materials and tensile the bond strengths determined by a direct tensile method for both the plane bond (control) and the proposed interlock bond. Results indicate that bond strength values for both the plane and interlock bond depends on the compressive strength of the interface materials. It also show that for the plane bond, bond strength values ranged from 1.57 N/mm2 – 1.97 N/mm2 at 28 days curing and for the interlock bond, its bond strength values ranged from 1.70 N/mm2 – 2.17 N/mm2 at 28 days curing age. The granite Mortar used at the interface of the Ferrocement skin and core material with an interlock bond has a bond strength value of 2.17 N/mm2 compared with similar interface material but with a plane bond, value of 1.97 N/mm2. The interlock bond strength improved by 9.22 % over that for the plane bond and granite mortar as interface material for Ferrocement Form is a promising material.