6.8 : Flow Table Test

The flow table test is an established method used to assess the workability of concrete, particularly useful for evaluating highly flowable concrete mixes. This test employs an apparatus that consists of a wooden board topped with a steel plate, collectively weighing 35 pounds. The board is connected to a base via a hinge and measures 27.6 inches on each side.

Concrete is placed within a truncated cone mold that is 8 inches high with an 8-inch base diameter and a 5-inch top diameter. The concrete is gently compacted, the excess is cleared away, and the mold is removed after 30 seconds.

The test procedure involves jolting the table 15 times at 4-second intervals by lifting the upper board to a height of 1.6 inches. This action causes the concrete to spread out from the initial cone shape. After the jolting, the extent of the spread of the concrete is measured parallel to the two edges of the table. The average spread is calculated to assess the concrete's workability. Specific values of spread are used to categorize the concrete's workability as either medium or high. This test provides crucial data on the concrete's ability to flow and settle under its own weight, reflecting its suitability for various construction applications where high fluidity and even distribution are necessary.