Remember that tests of fresh concrete are only as good at the sampling techniques used. For the slump test, conduct the test on a clean, level base. Remember that a delay of only 15 minutes can reduce the results of a slump test by 50 percent. Don't attempt to measure the slump of lightweight concrete using the same criteria you would use for regular weight concrete. Use an insulated box to store cylinders and avoid placing it in either a hot or dry location. Dampen the slump cone before filling it. When filled, lift the slump cone in a smooth, uniform manner. Don't lift the cone excessively fast or slow and refrain from jerky movements. Finally, don't use a piece of reinforcing to rod slump cones or strength cylinders.