UPDATES - UNIFORM SOIL GROUPS, MAXIMUM DENSITY OF GRAVEL, PERCENT COMPACTION

A proposal to use uniform soil groups for ASTM, AWWA, and ASCE pipe installation standards, manuals, and documents was first presented at the ASCE Conference “Pipelines 2009.” Since then two ASTM standards and an AWWA specification have been changed to incorporate the proposed soil groups. Currently, work is under way to use the uniform soil groups in three AWWA manuals and one additional ASTM standard. ASTM D 4253 has been the standard for determining the laboratory maximum density for cohesionless soils. The procedure used a vibratory table that involves an expensive and time consuming calibration process. There is now a new improved procedure, described in ASTM D7382, that replaces the vibratory table with a vibrating hammer. Also known as an impact drill, the tool creates a pulsing, hammering motion while the shaft rotates. The equipment is more durable than the vibrating table and provides more consistent results. The procedure uses a standard sand as a calibration procedure.