Use of the Soil Modulus for Compaction Control of Compacted Soils

Abstract

Insufficient compaction conditions can cause significant roadway infrastructure maintenance costs. Conventional compaction control, using nuclear methods, is based on the discrete in situ determination of the dry density and moisture content. Recently, there has been an increase interest in alternative methods for compaction control using intelligent compaction technologies. This method enables the continuous measurement of the soil modulus and the degree of compaction on the layer that is being compacted. Thus, the efficiency of the compaction process can be maximized. Although the adoption of this method is very promising, it constitutes a change of project specification for the contractors (i.e. use of the soil modulus instead of the dry unit weight). Furthermore, the role of dry unit weight, moisture content and matric suction on the soil modulus is still not well understood. This paper presents a review study of the effect of soil types, prepared under standard the same Proctor compaction energy, on the small-strain shear modulus. The results suggest that there seems to be a close relationship between the fines content and small strain shear modulus on the dry side of the optimum, whereas, its effect seems less evident on the wet side of the optimum.