Experiments and dimensional analysis of waste tire-based permeable pavements

This study investigates the stress–strain response of a novel high-porosity semi-bound soft–rigid permeable pavement blend prepared using rock- and tire-derived aggregates (RDA and TDA) bonded by a polyurethane (PUR) binder. A series of unconfined compression tests were performed on 36 mix designs (with different RDA and TDA proportions, PUR contents and curing durations) to identify the variables governing the stress–strain response. The greater the TDA content, the lower the mobilized strength (UCS) and stiffness (E₅₀), both following an exponentially-decreasing trend. Meanwhile, an increase in PUR content (i.e. increase in the number of inter-particle bonds) and/or curing duration enhanced the UCS and E₅₀. Unlike the UCS which often achieved a stabilized state at seven days of curing, the development of stiffness extended into higher curing durations. Applying the dimensional analysis concept, a practical modeling framework was proposed and validated (using an independent database) for the UCS and E₅₀, allowing these parameters to be simulated as a function of the blend's basic properties – that is, RDA (or TDA) content and its mean particle size, PUR content, curing duration, and dry density. The proposed models can be used with confidence for preliminary design assessments and/or semi-bound soft–rigid optimization studies.