ABSTRACT
Precast sandwich-elements made of ultra-high performance concrete as outer and inner shell material and air hardened foam concrete is subject of development and investigations. These multifunctional precast elements are intended to be used as wall elements for house constructions. For the optimisation of the foam concrete in terms of heat insulation and compressive strength, the concept of UHPC with optimized packing density of the fines (<125 µm) was combined with the aeration of concrete using aluminium powder or paste. Due to the packing density optimisation and the use of silica fume as reactive powder an autoclave hardening process is not necessary to gain a reliable strength. Moreover, parts of the quartz aggregates were replaced by lightweight aggregates in order to increase the heat insulation. Therefore, perlite in grain sizes from 40 µm to 3 mm were used gaining a good density (–0.5 t/m3) to strength (– 5 MPa) ratio already after 7 days (stored at 20°C, 65% r.h.).
