A test to determine the plasticity of concrete. A sample of wet concrete is placed in a cone-shaped container 12" high. The cone is removed by slowly pulling it upward. The slump cone is then placed beside the specimen of concrete and the number of inches from the top of the cone to the top of the specimen of concrete is the slump (see ASTM C143). If the concrete flattens out into a pile 4" high, it is said to have an 8" slump. This test is done on the job site. If more water is added to the concrete mix, the strength of the concrete decreases and the slump increases.