text: Get a slump cone, scoop and tamping rod from a concrete accessories supplier. As the concrete is being discharged from the truck scoop some concrete into your cone which is clean and held down on a flat level surface. Fill it up to a third full then give it 25 tamps with the rod. Top it up to two thirds full then give it another 25 tamps, then fill it right up to the top and give it another 25 tamps. Level off the top then slowly lift the cone off, allowing the concrete to slump down beneath it. Set the cone upside down beside the concrete, place the rod on top of the cone and across the top of the concrete and measure down from the rod to the top of the concrete. This measurement is the slump value of the concrete. Make sure you wear gloves when handling concrete. Don't use a bucket to move the concrete from the truck to the cone and don't twist the cone as you lift it off the concrete as a lot of people do. There you go! Good luck