Effects of ambient temperature and compaction delay time on the performance of cement-stabilised sand–gravel and the determination of allowable construction delay time

Abstract

ABSTRACT Compaction delay time (t d) refers to the period from the mixing of inorganic binder–stabilised materials to the completion of compaction; this process is affected by ambient temperature (T a). To characterise the effects of T a and t d on the performance of cement-stabilised sand–gravel (CSG) during construction, the reliability of the vertical vibration compaction method (VVCM) is evaluated and the effects of T a and t d on the mechanical strength and freeze–thaw resistance of CSG are investigated. Next, a predictive model for the allowable construction delay time is developed based on a non-loss principle with respect to pavement performance. The results show that the correlation between the mechanical strength of CSG laboratory specimens subjected to VVCM and field core samples can reach ∼90%. Higher T a and longer t d significantly reduce the mechanical strength and freeze-thaw resistance of CSG. Notably, when t d exceeds the initial setting time of cement, the average reductions in compressive strength, splitting strength, and freeze-thaw resistance of CSG are ∼29.3%, 31.3%, and 20.4%, respectively. The allowable construction delay time decreases linearly with increasing T a, showing a correlation of up to 99%. The predictive model can effectively determine the allowable construction delay time at any temperature.