ANALYSIS OF FRICTION AND LUBRICATION CONDITIONS OF CONCRETE/FORMWORK INTERFACES

Concrete friction plays a fundamental role during various stages of construction and public works operations, including pumping, formwork filling and the production of facings. A tribometer for fluid materials has thus been developed to better study this friction. Tests performed with certain modifications of interface conditions show that friction is governed by interfacial characteristics (e.g. type of demoulding agent, roughness, velocity, pressure). The investigation showed that the tribometer is sensitive to obtain a real understanding of the mechanical behaviour of the Self-Consolidating Concrete (SCC). The tests and observations made reveal that friction mechanisms depend on the properties of the interface. The interface appears to undergo two types of phenomena which depend of the pressure. The demoulding oil generates a reduction of the friction between the SCC and the formwork. Parameters specific to facing appearance are also addressed in this paper.