Determination of the in situ permeability of base and subbase courses

The development of a prototype in situ test device, designated the field permeability testing device for determination of the permeability of highway base and subbase courses is described and discussed. The feasibility of in situ permeability measurement techniques was investigted which led to the selection of the velocity method of in situ permeability determination for further development. A prototype field permeability test device was constructed and an extensive program of laboratory and field evaluations of this equipment was performed. It was concluded that the prototype field permeability test device developed satisfies project objectives and provides a convenient means for the determination of the in situ coefficient of permeability of highway bases and subbases with reasonable accuracy and reproducibility.