Concrete is often used to anchor a post within in the ground. You may need to reuse land for gardening or other construction where old posthole concrete still exists. Although the amount of work necessary to remove old posthole concrete depends on the size of the concrete "plug," removal typically only requires that you pry or pull the concrete from the ground.
Insert the end of your pinch-point digging bar or tamper bar into the ground on one side of the concrete.
Push and pull the bar back and forth to loosen the concrete within the soil.
Pull out the bar, insert it in the soil on the other side of the concrete and repeat.
Position the end of the bar under the concrete and push down on the bar to pry the plug from the hole. If necessary, ask another person to help you push down on the bar.
Punch the end of your pinch-point or tamper bar into the soil around the concrete to loosen the soil.
Dig around the concrete with a shovel---removing as much dirt as possible from around the plug.
Wrap and secure one end of a wire or chain from a pickup truck or tractor winch around the concrete.
Turn on the winch. If done correctly, the concrete should pull up and out of the hole.
If prying or pulling the concrete from the hole doesn't work, break it up with a long chisel and hammer or a jackhammer and remove in pieces to dispose of by wheelbarrow. When you break up the pieces, always start at the weakest point in the centre where some of the post remains and work your way out to the edges.
Wear safety goggles when removing post hole concrete as pieces of concrete can fly into the air from not only chiselling by hand or with a jackhammer, but also when digging.