Pouring Concrete Foundation Troubleshooting

Make sure the subgrade material meets the load-bearing capacity and is compacted to the set density.

Check that size and spacing of horizontal and vertical reinforced steel bar (rebar), welded wire mesh, lap lengths and the depth of concrete cover over the steel and meet set conditions. Make sure the steel is supported with the proper ties, chairs and spacers so it won't move during the pour. The rebar should be clean and free of rust or oil or any substance that would impair bonding to the concrete.

Brace and support formwork to a condition where it won't flex or move during the concrete pour. Coat with approved form oil.

Plan the placement and number of joints before pouring concrete. Clear circulation routes for concrete delivery and plan sequence for pouring. Size the crew appropriately for efficient pouring and finishing for the work. Check that all preparation is complete and tools are available before the concrete arrives.

Select the method of delivery for the concrete that requires the least transportation. Verify from the driver's paperwork that the mix complies with the specified strength.

Start the pour at the lowest elevation or from the corners of the formwork. Pour vertically from the truck from a height of 5 feet or less.

Use the mechanical vibrator for internal vibration as the concrete is placed. Put the vibrator into the concrete quickly and pull it out slowly. Follow a consistent route with the vibrator for full coverage. Vibrate evenly so that the concrete settles in all the forms. Don't spread concrete with the vibrator.

Vibrate the surface of structures with the mechanical screed as required. Keep a small amount of concrete in front of the beams of the screed to avoid formation of holes. Screed to the level of the formwork.

Time the placement of concrete joints carefully when the concrete is not too wet or too dry. Tool joints with trowels or suitable hand tools.

Leave the formwork in place during curing. Cure with the proper time frame for the environmental conditions. Maintain curing temperature and moisture content for the concrete for at least three days and seven, if possible.