Modelling of the variation of granular base materials resilient modulus with material characteristics and humidity conditions

Abstract

This study aims to quantify the susceptibility of granular materials used in pavements to changes in moisture content and propose a correlation model to incorporate this susceptibility into seasonal analyses. The fines content and the percentage of fractured coarse aggregates were identified as direct indicators of the resilient modulus susceptibility to changes in water content. The results showed that the percentage of fractured coarse aggregates particles (FR) has a more significant impact on the resilient modulus (Er) of crushed granular materials used in pavement construction than the combined indicator of the fines content and sample volumetrics (n_f). Crushed granular materials with a higher percentage of fractured coarse aggregates are relatively insensitive to changes in the degree of saturation, but become more sensitive as the fine fraction porosity decreases. An adjusted model was proposed based on the existing formulation, but considers a complex parameter to describe and adjust the sensitivity of base granular materials to variations in moisture content with respect to fabrication characteristics, fines content and volumetric properties. The model shows that the variation of Er values is below ±10% for fully crushed granular materials. However, it reaches approximately ±12% for materials with 75% of crushed coarse aggregates and +40% and −25% for materials with FR ​= ​50%. This model could help select good aggregates characteristics and adjust grain-size distribution for environments where significant moisture content variations can occur in the pavement system, such as in the Province of Quebec (Canada). As it is based on parameters that can be easily determined or estimated, it also represents a valuable tool for detailed design and analysis that can consider material characteristics.