Concrete replacement is an important part of programmed and emergency maintenance. Set your mind to doing it right, and cement solid work practices. In the aggregate, consistency is vital. Slump and you’ll get your fly ash hurt. Bull doesn’t float with concrete work. Safety first is the best cure to curb injuries.
Make informed decisions about whether the work is necessary. Full depth repairs are often made on
concrete pavement where joints failed. The tendency has been to make too many repairs, particularly on projects with overlays in excess of 3 in. When a joint is cut out and patched there are then two new joints where previously there was only one. In the long term this can create more problems than it solves.
A normal crew size is 8 or 12. Good organization is required to decrease the time this hazardous operation is in effect on any roadway section. Extensive patching operations shall be under the supervision of a Maintenance Supervisor who assigns workers to various crew components as needed.
Work must be conducted with as little inconvenience to traffic as possible. Inconvenience equates to unsafe because it alters driver behavior. At least one lane must be available for traffic use at all times and free of obstructions, including ramps at interchanges. All lanes should be open to traffic by 5 p.m. Friday. For major holidays and extended weekends all lanes should be open to traffic by 12:00 noon of the day preceding the period or holiday.
Crews should be protected by working them between or behind equipment. Flaggers are to be used as
needed. All patches should be barricaded and work zones and other traffic control must be set up in
accordance with the TCFO guidance.
The largest slab normally removed without doing damage to subgrade and to ensure the slab remains in place is six feet. There may be special equipment available to remove larger slabs. Use the right equipment for the job at hand.
Normally, no patches or open holes should be left overnight. If it’s necessary to do so, set up measures as indicated in the TCFO. A crew member must be designated to patrol the area when barricades are in place and workers are not present to assure the safety devices are working. If this is necessary at night the worker must also check all the traffic control devices.
Wet concrete and cement contain strong alkalis that can cause serious burns. Keep it off your skin, and wear waterproof boots. Concrete can soak through regular boots and clothing, and cause burns as long as several days later. To understand how awful wet concrete is on your body, consider that the pH level of human skin is about 4.5. The pH level of the strongest acids (like battery acid) is about 1. The pH level of wet concrete is about 13 on the alkali side. Like your momma said, “If you gotta play with it, at least don’t get it on ya.”
Concrete replacement is some of the most difficult and dangerous work MoDOT does. Good planning and not cutting corners can ensure a concrete blow-up won’t blow up in your face. If you would like more information on concrete replacement, contact district Risk Management staff.
Concrete Replacement Safety