Slump Test

The slump test is the most commonly used method of measuring the consistency of concrete. It is not suitable for very wet or very dry concrete. It does not measure all factors contributing to workability, nor is it always representative of the placeability of the concrete. however it is used conveniently as a control test and gives an indication of the uniformity of concrete consistency from batch to batch. Repeated batches of the same mix, brought to the same slump, will have the same water content and water-cement ration provided weights of aggregate, cement, and admixtures are uniform and aggregate grading is within acceptable tolerances.

The slump test should be performed in strict accordance with requirements of ASTM C 143: 2000. Tests are usually made at the point of placement and should be made whenever specimens are molded for strength testing. Slump tests may be carried out at the mixing plant in order to check the uniformity of batching operations.

References

Paul Klieger and Joseph F. Lamond, editors (1994) Significance of Tests and Properties of Concrete and Concrete-Making Materials (4th ed.) ASTM

Further Reading

[1] Modified slump test

[2] ASTM C 143 2000 Standard Test Method for Slump of Hydraulic Cement Concrete