What is the slump test and what does it measure?

The slump test measures concrete workability - the ease with which fresh concrete can be mixed, placed, compacted, and finished. A cone mold is filled with concrete in three layers, each rodded 25 times. The cone is lifted, and the vertical settlement (slump) is measured. Typical slump values: 25-50mm for pavements, 75-100mm for normal reinforced concrete, 150-175mm for congested reinforcement. Higher slump indicates more workable but potentially weaker concrete.