DELIVERY DEVICE FOR CONCRETE ADMIXTURES AND PROCESS FOR RETARDING THE SETTING OF SURFACE PORTION OF CONCRETE

摘要

A delivery device for concrete admixtures, in the form of a film (1) of water-soluble material, having a concrete admixture incorporated within the film (1). The film can be attached to a formwork for concrete, e.g. by an adhesive (2A), and has a protective liner (4), which is removable to allow the water in the concrete to dissolve the film (1) and release the admixture into the concrete. The film (1) contains the required quantity of admixture and is weather-resistant and substantially time-insensitive. A process for retarding the setting of a surface portion of concrete by using the delivery device is also claimed.