Fibre Reinforced Cement (FRC) is a durable, fire and corrosion resistant material widely used in the construction industry. Coupled with the low cost of Portland cement, these properties make it ideally suited for applications such as roofing tiles and sidings. However the production of cement is associated with a large CO2 ‘footprint’, for each tonne of cement produced nearly one tonne of CO2 is emitted. This has resulted in FRC becoming stigmatised as a ‘dirty’ material. In addition the high density of cement and hence FRC products results in high transport costs for the producers and high end user installation costs.
In order to improve the poor environmental impact of FRC and improve its specific properties, we will develop a cement based, nanotechnology enhanced material produced by a low energy consuming process. The material will consist of a cement based sandwich consisting of a foam cement core and fibre reinforced cement ‘skins’. The foam core will be produced using a nanoscale foaming agent to ensure the formation of an optimum closed cell foam structure with a micro-scale cell size with a narrow cell size distribution. Both the foam and the ‘skins’ will be reinforced with nanoclays to improve both the mechanical and transport properties of the material. The foam cement core will result in a lower density compared to existing FRC, whilst the reinforced skins will ensure the mechanical properties are improved. Added functionality in the form of decreased thermal conductivity and increased sound insulation properties will result from the foam core.
The material will be produced by a low energy multilayer extrusion process in which both the foam cement core and fibre reinforced skins are simultaneously formed such that no discontinuity is formed between them. By using a foam core and replacing part of the cement with materials such as fly ash and silica fume, the CO2 footprint of the material will be significantly reduced compared to existing FRC.