Standard Test Method for Determining the Peel Strength of GCCM Materials

Abstract

4.1 This test method is applicable for testing GCCM materials in both a cured and uncured state. This determines the peel strength of various layers of these multilayer materials to determine critical interface strength. It is used with a constant rate of extension type of tensile testing machine. 4.2 The peel strength provides a measure of the strength of the connection between the top and bottom layers due to any linking elements present between them (such as connecting fibers/yarns or other linking elements), or the strength of the connection between the additional functional layers attached to the top or bottom layer that are necessary for the GCCM to function as a composite. In particular: 4.2.1 Uncured peel strength is important when installing a GCCM because the top and bottom layers must be securely connected in order to constrain the cementitious material when dragging/tensioning the GCCM into position. If the top/bottom layers become detached during handling, the cementitious material is no longer constrained and may overhydrate or can potentially fall or wash out from the GCCM, causing the set composite to have poor mechanical properties. 4.2.2 Cured peel strength is important in an installed GCCM because if the top layer is insufficiently attached it may become detached due to hydraulic shear or wind loads, or become completely detached and washed downstream, causing blockages and environmental damage. If the additional functional layers are poorly attached to the top/bottom/other additional functional layers, the layers may no longer act as a composite, which could lead to durability issues and multiple potential failure modes.