Typically, we perform field density testing of soils and stone base material per ASTM D 6938 using nuclear density gauges to determine the moisture content and in-place density. Soil testing can be performed on a full time basis when multiple lifts of fill will be placed during our inspection or on an as-needed basis when the contractor only places one or two lifts in a day. Some projects require verification of nuclear density results by performing sand cone tests per ASTM D 1556. When laboratory proctors are not available, we can determine the maximum density of the tested soil in the field by comparison of a one point proctor with established family of curves per VTM-12.
Prior to the placement of fill soil we evaluate the suitability of the existing subgrade by observing proof rolling operations performed by the contractor using loaded rubber tire vehicles. Areas of unstable soil are identified in the field and, if required, test pits are excavated to determine the depth, extent and cause of the unstable soils. We then recommend the best means of stabilization, whether drying, stabilizing the soils with lime or cement or undercutting. During site work activities, we can monitor borrow pits and fill soil materials, soil moisture content, truck counts, topsoil stripping, as well as monitor lift thicknesses, slope reconstruction and placement of stabilization geotextiles.