This paper presents an experimental study, which has been lacking to date, into the properties and applications of waste glass–plastic cementitious (WGPC) composites incorporating recycled aggregates as a full replacement of natural aggregates, with direct application in highly eco-efficient construction components. Detailed experimental assessments of the fresh properties, strength and durability characteristics of such composites are undertaken. Particular focus is given to the mix rationale and optimisation process as well as possible routes of exploitation of such materials in construction elements. The experimental assessments showed that such composite materials meet the strength and durability criteria for direct application in practice. The best balance in terms of strength and workability was achieved for a waste glass-to-plastic aggregate ratio of 92/8. The presence of relatively large amounts of recycled waste glass particles with small sizes acted as secondary hydration products and contributed to achieving an adequate strength of the material. Besides a lower unit weight and superior thermal properties compared with those of conventional concrete, WGPC components have shown a reliable behaviour under vehicle impact loading and potential wider application in sustainable non-structural construction applications.