Experimentalgebäude aus Infraleichtbeton - monolithisch und hochwärmedämmend

High thermal insulating Infra lightweight concrete -experimental building constructed with weight-optimized exposed concrete

Combining the physical characteristics of lightweight concrete that provides highly efficient heat insulation with the appearance of a state-of-the-art architectural concrete makes it possible to construct buildings that merge the expression of concrete with the energy efficiency specifications for external structural components. The aim of the research project conducted by the University of Kaiserslautern was the development of highly insulating monolithic lightweight concrete construction components made of exposed concrete. The composition of the Infra lightweight concrete, (i. e. recycled expanded glass and blast furnace cement reduced in Portland cement clinker) developed with regard to sustainability aspects, had to meet high requirements in terms of bulk density, durability and thermal conductivity. The self-compacting lightweight concrete had to reconcile conflicting requirements, such as a sufficiently high compressive strength and a low bulk density, as well as a low water absorption rate despite the expanded cement matrix. The self-compacting flow properties without separation were achieved by the use of a PCE-super-plasticiser in combination with a stabiliser. The desired low bulk density required the use of a foaming admixture to expand the cement matrix. To improve durability, further shrinkage-reducing and water repellent admixtures were used. For dry bulk densities of well under 700 kg/m³, a thermal conductivity value of λ = 0.15 W/(m·K) was achieved. The transfer possibilities presented by the findings from the laboratory were verified by the construction of a research building made of Infra lightweight concrete at the premises of the University of Kaiserslautern. Continuous measurements via multi ring sensor electrodes (MRSE) provided information on temperature and moisture changes during exposure to natural weathering.