Characterizing tribological behavior of fresh concrete against formwork surfaces

Abstract

The friction of concrete on the interior skin of formworks takes place during the pouring of concrete into the molds. The present work investigates the friction of a granular material (i.e. fresh concrete) against metallic and polymeric surfaces. Interfacial behavior between different formulated concretes and formwork skins is characterized using a plane-plane tribometer dedicated to concrete tribometer. The formwork surface is measured before and after testing to quantify the wear issue. A Coulomb friction law is observed within the range of tested normal pressures. Tribological tests reveal that friction mechanisms depend on the interface properties. Two underlying mechanisms are hypothesized to explain the wearing of the formwork skin: a granulate-formwork solid-solid friction and a capillary-dominated friction.