Utilizing Dielectric Constant and Electrical Conductivity to Estimate Cement Content in Stabilized Subgrade Soils

Abstract

Cement stabilization is a standard method used to strengthen fine-grained soils that are locally available and prepare them for pavement construction. Flexible pavements over cement-stabilized soils commonly experience mild reflective cracking originating from the shrinkage cracks on top of the stabilized layer. The severity of this form of reflective cracking is correlated to inadequate soil–cement construction practices which include thin stabilized layers, low compaction, deviations in cement content from the mix design, and rapid moisture loss. Consequently, these construction issues can significantly reduce the flexible pavement strength and overall life cycle. In this study, a non-destructive quality assurance method using a ground penetrating radar (GPR) and percometer was developed to capture stabilized soil’s inconsistent cement content and hydration rates. A predictive model derived from laboratory testing was created based on the distinct hydration rates, dielectric constants, and electrical conductivities associated with different water and cement contents. Laboratory testing shows that GPR can detect these inconsistencies in cement-stabilized layers within the first seven days after construction through non-destructive testing.