Multi-functional Concretes for Structural Wall Elements

Abstract

Due to the increasingly stringent specifications based on global energy saving regulations [4], structural construction, which initially only had mechanical functions, by now also have to have insulation features. An established standard solution are wall elements with heat insulation network systems attached to the supporting system. These heat insulation network systems usually consist of several layers of diverse material groups, mostly prepared of expanded, heat-insulating polystyrene foam (EPS). This construction is both expensive and energy consuming and makes a sorted recycling after removal almost impossible, requiring dumping in almost all cases. Another conventional construction material with good heat insulation characteristics is aerated concrete, which however has to be autoclaved with a high energy input. Commercially available, physically or mechanically foamed concretes are seldom used due to their low compressive strength and fluctuating characteristics. An alternative for the construction of both supporting and heat-insulating walls is the combination of chemically foamed, air-hardening, mineral-bound foam (CAMF) and ultra-high performance concrete (UHPC). CAMF has been structurally optimized towards having good heat insulation characteristics and, due to its stability, can at the same time take the load transfer of the wall elements. The UHPC is attached as a shell to protect the CAMF and can additionally be used as a designed or functionalized surface.