Comparison of lightweight mortars manufactured with virgin or recycled polystyrene

In recent years, energy saving in buildings prescribes limits on thermal transmittance of opaque structures that can be achieved with the use of materials with low thermal conductivities. Mortars and concretes lightened with polystyrene pearls belong to this class. In this work, the performance of lightweight mortars manufactured with virgin polystyrene is compared with that of mortars manufactured with recycled granules of polystyrene at the same volume dosage. Six mortar mixtures with water/cement = 0.55 by replacing the 33% - 66% - 100% of sand volume with virgin or recycled polystyrene are manufactured. The obtained results show that, at the same volume dosage, the replacing of virgin polystyrene with recycled one improves the mechanical performance of mortars without significant variation in the capillary water absorption and water vapour permeability. The use of recycled polystyrene increases the equivalent thermal conductivity of mortars that can be compensated with a higher dosage of polystyrene. The use of recycled polystyrene allows a significant economical savings during the production phase of mortars and a certain insulation degree.