The thermal and mechanical performance of cement-based composites with enhanced thermal insulation properties Z. Pavlík, M. Záleská, M. Pavlíková & R. Černý Department of Materials Engineering and Chemistry, Faculty of Civil Engineering, Czech Technical University in Prague, Czech Republic Abstract Cement-based composites are characterized by their good mechanical properties but they often lack a thermal insulation capability. In this paper, crushed waste polypropylene (PP) originating from PP tubes production is applied for the preparation of composites with enhanced thermal insulation properties which can be used for a reduction of heat transfer in contemporary buildings. In the composite design, the natural aggregate is substituted with the plastic waste in amounts of 10, 20, 30, 40, and 60% by mass. A reference mixture without plastic addition is studied as well, for the sake of comparison. For the researched PP granular aggregate, thermal conductivity, thermal diffusivity and volumetric heat capacity are measured in dependence on powder density and material compacting using an impulse technique. In this way, the possibility of improvement of thermal insulation properties of cement-based composites is accessed. The assessment of heat transport and storage properties of plastic waste represents new information for the proper design and development of lightweight composites suitable for the improvement of the thermal stability of buildings. For the developed composites, basic physical, mechanical, and heat transport and storage properties are measured. The thermal transmittance and thermal resistance are then calculated, assuming a typical arrangement of a building floor structure. The application of PP results in an improvement of thermal insulation properties with an acceptable decrease of mechanical resistivity. This gives a good prerequisite for further investigations of composite materials with enhanced thermal insulation function. Keywords: recycled plastic aggregate, cement-based composite, heat transport, thermal resistance, thermal transmittance. www.witpress.com, ISSN 1743-3533 (on-line) WIT Transactions on Engineering Sciences, Vol 83, © 2014 WIT Press Advanced Computational Methods and Experiments in Heat Transfer XIII 251 doi:10.2495/HT140231