How do expansion joints in concrete work?

Answer by  embockjr (709)

Expansion joints are designed to reduce stress in concrete and to insure that the material will not crack in other than acceptable locations. The expansion joints are employed in roads, driveways, walks, etc. If expansion joints are not utilized, stress build-up in the material will lead to the break-up of the work - as noted in cracked driveways, etc.

Answer by  Liz59 (10966)

Well they will expand the concrete. It is actually a great technique if you want to make a concrete sidewalk or driveway. This will eventually allow the concrete to expand.

Answer by  LeheckaG (1826)

Temperature changes cause concrete to contract & expand, appropriately spaced expansion joints allow the concrete to do so without cracking. Concrete expansion joint gaps are circular-concrete/masonry-saw cut, or created by concrete-forms made of metal, styrofoam, or wood; and water/weather-sealed with hot tar, rubber, or silicone.

Answer by  becki (229)

Expansion joints work by allowing the concrete to move slightly in warmer and colder weather. These are necessary in order for the concrete to remain intact and not break or crack . If the concrete did not have expansion joints, it would more than likely crack from the extremes it faces of heat and cold.

Answer by  itsame (275)

When concrete heats or cools it expands and contracts respectively. Expansion joints keep it from fracturing by allowing it expand and contract freely.

Answer by  eyeguy (3760)

When the ambient temperature changes in the area around the concrete project the expansion joints allows for a cushion of support to prevent cracking during expansion or shrinkage

Answer by  missym1251 (96)

The joints/seams are filled with butle which allows for weather causing expansion and contraction so that the concrete doesn't crack.