The American Society for Testing and Materials (ASTM) has developed two standard methods for measuring the consistency of unhardened mortar: the flow table procedure (ASTM C 109) and the cone penetration procedure (ASTM C 780). ASTM is now considering standardizing a third method, the Conway penetration procedure.
THE FLOW TABLE PROCEDURE
The flow table procedure for measuring mortar consistency is intended for laboratory use only. The test procedure is described in ASTM C 109, Standard Test Method for Compressive Strength of Hydraulic Cement Mortars. The flow table itself is described in ASTM C 230, Standard Specification for Flow Table for Use in Tests of Hydraulic Cement.
THE CONE PENETRATION TEST
The consistency of mortar in the field can be measured using the cone penetration procedure. The cone penetration procedure is described in ASTM C 780, Standard Method for Preconstruction and Construction Evaluation of Mortars for Plain and Reinforced Unit Masonry. Instead of the flow table, this test uses a cone penetrometer, which is a modified version of the Vicat apparatus used in ASTM C 187 to measure the consistency of hydraulic cement.
THE CONWAY PENETRATION PROCEDURE
ASTM is now studying another method of measuring mortar consistency as an alternative to the C 780 test method. Called the Conway penetration procedure, this method was first recommended by Tim Conway of Santee Cement Company. If the Conway method is adopted either it or the cone penetrometer may be used.