Multicriteria analysis of the components of ecological paving stones made from plastic and glass waste, and granular reinforcements

The use of plastic waste as a resource in construction applications is an opportunity for environmental protection, conservation of natural resources and reduction of pollution. Unfortunately, they don't always withstand the stresses to which they are subjected, leading to subsidence and collapsing. An analysis of the causes using the Pareto curve shows that 74.47 % of the causes of this collapse are due to poorly formulated mixes and poor choice of raw materials for the composite. The compressive test carried out on the first sample of pavers studied showed a maximum compressive strength value of 4.6 MPa, which is below the standard requirements. As a result, the pavers were considered unsuitable for use on a T5 road. Through the use of the SUPERDECISION software, we were able to identify two favourable constituent materials - glass/glass waste and gravel - for the production of composite paving stones. By adding low-density plastic waste, collected, cleaned and crushed in the form of aggregates, we obtain a compressive strength of 7 MPa with gravel and 8 MPa with glass waste. These values are below the recommendations of the NF EN 1339 standard (Rc ≥ 20 MPa) for T5 traffic. The best composition for ecological paving is therefore (PET/PP/PEBD) + sand + glass (50/12.5/37.5). Analyzing these results shows that the raw materials used for ecological paving should be adapted to the loads.