In civil engineering, an increasing demand for lightweight concretes exists, because a lower density results in significant benefits for structural elements. Polystyrene foams may be used in the fabrication of lightweight concretes with a large density range. In this work, the influence of fine grained sand (<1mm) additions of 5, 10 and 20% on the properties of a composite of cement with styrofoam additions of 20, 40 and 60% has been studied. The composites were characterized by their density, porosity and compressive strength after 28 days. The density of the composites varied between 1250 and 1600 kg/m³ with a strength of 18 and 9 MPa for additions of 20 and 60% styrofoam, respectively. The increase of the fraction of sand from 5 to 20% promoted the increase in bulk density and modulus of the composites. The effect of the addition of sand on the porosity and mechanical strength exhibited variation indicating the packing factor of the particles as the main responsible for this behavior. The composites investigated exhibited a uniform distribution of the polystyrene spheres, allowing their use for non-structural purposes.
composite particulate; cement; styrofoam
