Discussion of "compaction and strength behavior of tire crumbles-fly ash mixed with clay" by Akash Priyadarshee, Arvind Kumar, Deepak Gupta, and Pankaj Pushkarna

The dimensional analysis concept was successfully extended to the clay–tire crumbles–fly ash CBR problem, thereby leading to the development of a simple and practical dimensional model capable of predicting the CBR (at both unsoaked and soaked conditions) as a function of the mixture’s basic index properties, i.e., stabilizer content, initial placement (or compaction) condition, specific surface area, grain-size distribution, and curing time. The predictive capacity of the proposed dimensional model was examined and further validated by statistical techniques. The proposed dimensional model contains a total of four model (or fitting) parameters, which can be calibrated with little experimental effort and further implemented for predictive purposes. The model parameters can be adequately estimated by a total of four unsoaked or soaked CBR tests. Four scenarios consisting of the clay soil with no additives, a desired clay–tire crumbles mixture (no fly ash), a desired clay–fly ash mixture (no tire crumbles), and a desired clay–tire crumbles–fly ash mixture are recommended for the calibration phase. The choice of tire crumbles and fly ash contents are arbitrary; however, from a statistical perspective, median contents are expected to yield a more reliable estimate of the model parameters (Mirzababaei et al. 2018).