With the development of new materials for use in buildings and infrastructure we aim at addressing fundamental issues of the construction industry, including reduction of the environmental footprint, use of recycled, marginal and alternative materials, and design of multifunctional materials. A special challenge for the application of advanced building materials is posed by the different length scales, spanning from the nano- and microstructure up to the scale of the structure, on which their performance depends. This requires a multi-scale modeling approach, taking into account the coupled mechanical, physical, thermal and hygroscopic behavior. A further complication for modeling the properties of building materials comes from their often porous matrix (made, i.e., of concrete, wood, natural and artificial stone), causing a strong interaction with moisture that effects volume change, mechanical properties and durability.

Three dimensional microstructure obtained by Focussed Ion Beam Nanotomography of a cement paste made with blast-furnace slag cement (above) and segmented porosity from the same microstructure (below). The cube size is 14 µm while the voxel size is 20 nm (from Leemann, Loser, Trtik, Münch, cemsuisse report, 2010). From the pore structure of the cement paste, transport properties and shrinkage can be pre-dicted.

Empa's advanced knowledge in materials science and technology, high-level experimental and analytical equipment and computational modeling shall be used to address challenges in three areas:

Development of low environmental footprint construction materials by promoting cementitious materi-als and low CO2 concrete composites, applying alternative or recycled binders for new energy saving road materials, upgrading wood as high performance renewable construction material, and fostering the development of adaptive hygrothermal and highly insulating aerogels.

Surface modifications of construction materials by using physical, chemical and biological treatments; promoting the interaction of materials with coatings, adhesive and binders, to develop e.g. moisture regulating coatings for facades, and eco-friendly intumescent flame retardant coatings and layers.

Enhance fundamental understanding of porous building materials (physical, mechanical, chemical and biological processes, 3D characterization).