How to Pour Concrete Around Manholes
- 1). Contact your local government's highway department. Different municipalities will have different regulations for proper manhole installation or repair. Complying with all local municipality guidelines and requirements for manholes can prevent you from accruing fines or having to go back and fix your work.
- 2). Prepare your concrete mixture by mixing the bagged concrete powder with water in the mixing bucket. Wear waterproof gloves and safety goggles, as the concrete mixture can be damaging if it comes in contact with your skin. Follow the directions printed on your bagged concrete powder for the proper ratio of concrete powder to water. Mix the concrete in the bucket using a hoe.
- 3). Pour the concrete into the recess that needs to be reinforced around the manhole pipe. Manhole pipes are contained within localized slabs that are larger than the manhole shaft. Often, this space will have been previously supported with steel rods and other equipment. Allow the concrete mixture to fill all the space from the floor to 15cm above the manhole top. If you notice bubbles forming in the concrete mixture, use a hoe to force the air out. Bubbles can dry into the concrete, making it weaker and more liable to crack.
- 4). Use a trowel to form the concrete paste against the top of the manhole. The manhole cover will not be placed on top of the manhole shaft at this point, so make sure that no excess concrete is drying where the cover will be placed. Form the concrete tightly around the sides of the manhole shaft, making sure that the concrete sits 15cm above the top of the manhole shaft.
- 5). Allow the concrete to set and dry before performing the additional steps required to finish your manhole work. You most likely will not have the time to allow the concrete to fully cure, or reach its design strength; that can take up to 30 days. However, you will need the concrete to set and dry so it will not interfere with placing the manhole cover over the shaft, applying a pavement or soil layer over the concrete, or any other necessary steps.
