Self Expanding Cork Type III fillers are an exclusive formulation, produced from clean select granulated cork particles bonded together securely with a synthetic resin. Self Expanding Cork expands upon exposure to moisture and weather to develop an interference pressure seal within the concrete joint. Self Expanding Cork Type III fillers are suitable for filling expansion joints in areas such as irrigation canals, culverts, dams, reservoirs, sea walls, waste water treatment plants, flood walls, spillways, filtration plants, bridges, swimming pools, subways, and more. Self Expanding Cork Type III fillers are compatible with most hot-pour and cold applied joint sealants.