A friction reducer (OD = 36 mm) combines two purposes. It connects the piezocone, electrical CPT cone or mechanical cone to the first CPT sounding tube and it reduces the lateral friction on the string of CPT sounding tubes during cone penetration testing.
The friction reducers are available either with cams or with a ring. The ring type friction reducer is primarily used in clays and clayey soils. The cam type friction reducer is mostly used in sands. For more background reading, please consult “Cone Penetration Testing in Geotechnical Practice” by T. Lunne a.o.
Friction reducers come in various sizes and lay-outs in order to meet the industry’s needs.