Influence of the nature of the demoulding agent on the properties of the formwork-concrete interface

Release agents are a significant source of pollution in the construction and prefabrication industries. Conventional products are known to be toxic for humans and the environment. New formulations based on vegetable esters have appeared on the market to mitigate against this drawback. However, more knowledge is required about the properties and behaviour of these products to make them more attractive for industry. Understanding the phenomena that occur over the formwork - oil - concrete interface is a real challenge. The present paper begins with a physicochemical survey of release agents by defining the formwork - oil and oil - concrete interfaces. It then characterises the formwork - oil concrete interfaces by dynamic studies (tribometer). Physicochemical mechanisms are proposed.