Together with his team, Zwicky experimented with the content and granularity of the wood as well as diverse additives and subsequently subjected the various blends to rigorous tests. The main difference from classical concrete is that the gravel and sand content is replaced with finely ground wood. In other words, sawdust rather than small stones is mixed in with the cement. Thanks to the high wood content, the new building materials show good flame retardance and act as thermal insulation. “They weigh at most half of what normal concrete weighs — the lightest of them even float!” says Zwicky. Moreover, as the materials are based largely on renewable resources, after dismantling they can be reused as a source of heat and electricity. The wood content can be burnt in waste incineration, although for everyday use it conforms to fire protection standards.
Initial 1:1 stress tests show that the new wood-based concrete is also suitable for slab and wall elements and can provide a load-bearing function in construction. The process is also suited to prefabricated units. In this context, in particular, the Fribourg group would like to deepen their expertise through a broader range of tests. The researchers want to find out which wood-concrete composite is best for which applications, and how it can be produced efficiently.
Source: Science Daily