Correlation between adhesion energy of release agents on the formwork and demoulding performances

摘要

To ensure an easy demoulding of the concrete, the release agent must form a homogeneous film on the formwork to resist the casting concrete. The adherence of oil with the support was studied via the solid/ liquid energy adhesion. This energy was calculated using the Zisman equation involving the angle of drop and the surface tension. Various formulations were studied, in order to establish correlations between their composition and the interfacial properties. Formwork release tests were performed to assess cladding aesthetics; it was possible to define a minimal level of adhesion energy to meet the facings quality after concrete demoulding.