Concrete stress members compound layered sheathing - has heated inner plastics layer swelling into cavities in outer insulating layer

摘要

Concrete load bearing structures are prestressed, when concrete is hard, by stress members (1) sheathed in two or more layers of plastics. The inner layer is deformable and joins firmly onto the outer layer under heat hardening. The outer layer is of heat insulating material (3) with linked hollow spaces, sealed on the concrete (5e side by a membrane, but open on the plastics layer side. The plastics (2) has a propellent reacting to heat, which causes it to swell and penetrate the hollow spaces and consolidate the insulating layer to transmit bonding forces. This makes favourable heat insulation qualities available during heating.