Predicting the Compactability of Artificially Cemented Fine‑Grained Soils Blended with Waste‑Tire‑Derived Aggregates

Abstract

This study investigates the possibility of extending the specific gravity ratio (SGR) modeling framework, originally developed for predicting the compaction properties of unamended fine-grained soils (with no binder) blended with tire- derived aggregates (TDAs), to artificially cemented soil–TDA blends. This was achieved by performing comprehensive statistical analyses on a large and diverse database of 87 fine-grained soil–binder–TDA compaction tests, covering a wide range of soil plasticity and including a variety of chemical binders (cement, lime, fly ash, slag, and liquid polymers) and sand-sized (0.075–4.75 mm) TDA prod- ucts. The optimum water content (OWC) and maximum dry unit weight (MDD) for any fine-grained soil–binder–TDA blend (constant binder type and content) can be expressed as functions of the OWC and MDD measured for the soil– binder mixture (with no TDA), along with the soil–binder (SB) to soil–binder– TDA (SBT) SGR, as wSBT opt = wSB opt (SGR)𝛽M and 𝛾SBT dmax = 𝛾SB dmax (SGR)𝛽D , respectively. It was demonstrated that reliable predictions (across different fine-grained soils, binders, TDA particle sizes/shapes, and compaction energy levels) can be achieved by adopting the same unique reduction rate parameters of βM = − 0.967 and βD = − 0.509 used for non-cemented soil–TDA mixtures. Attempts were also made to identify causal links between these reduction rate parameters and basic soil properties. It was shown that βD can be expressed as a linear–log function of soil activity. The 95% lower and upper (water content) agreement limits between the predicted and measured OWC values were obtained as − 1.70% and + 2.01%, both of which can be deemed acceptable for practical applications (e.g., preliminary soil–binder–TDA mixture-design evaluations). For the MDD predictions employing soil activity, these agreement limits were calculated as − 0.50 and + 0.54 kN/m 3 ; these small MDD limits are also deemed acceptable for practi- cal applications.