Usually, expansion joints should be no farther apart than 2 to 3 times (in feet) the total width of the concrete (in inches). So for a 4 inch thick concrete slab, expansion joints should be no more than 8 to 12 feet apart.
Do you need to put expansion joints in concrete?
Expansion joints are virtually never needed with interior slabs , because the concrete doesn’t expand that much—it never gets that hot. Expansion joints in concrete pavement are also seldom needed, since the contraction joints open enough (from drying shrinkage) to account for temperature expansion.
Does reinforced concrete need expansion joints?
All concrete will shrink slightly as it dries and, when it’s set, will expand or contract depending on the ambient temperature. To prevent cracks from forming, concrete expansion joints should be incorporated to allow for movement, particularly in slabs with a surface area exceeding 6m2.
Can you pour concrete without expansion joints?
Expansion joints are virtually never needed with interior slabs , because the concrete doesn’t expand that much—it never gets that hot. Expansion joints in concrete pavement are also seldom needed, since the contraction joints open enough (from drying shrinkage) to account for temperature expansion.
What happens if you don’t put expansion joints in concrete?
Concrete expansion joints give the slabs just enough room to move which helps prevent cracks & buckling. Without these joints, even a little movement creates pressure and stress on the concrete . Eventually weak spots can crack or buckle.
What is the difference between expansion joints and control joints?
Control joints can be isolated within the plane being treated (brick facades, concrete sidewalks) while expansion joints must bisect the entire structure thereby creating a gap throughout all of the building elements —foundation, walls, curtainwalls, plaza decks, parking decks, floors, and roof.
What material is used for expansion joints in concrete?
Minimize Concrete Cracking and Damage with Expansion Joints. ASPHALT EXPANSION JOINT is composed of a blend of asphalts, vegetable fibers, and mineral fillers formed under heat and pressure between two asphalt-saturated liners. It is waterproof, permanent, flexible, and self-sealing.
Do garage floors need expansion joints?
Many people understand that wood shrinks and expands as temperature and humidity ebb and flow through the year. But the same thing happens with concrete. That’s why it is necessary to include expansion joints along the edges of the concrete garage floor as well as around posts or other protrusions in the slab.
How do you fill concrete expansion joints?
Expansion joints must be sealed with a flexible sealant, like QUIKRETE® Self-Leveling Polyurethane Sealant or QUIKRETE® Non-Sag Polyurethane Sealant ...or an expansion joint strip, to prevent water from penetrating the joint and deteriorating the sub-base.
What is the best concrete expansion joint material?
Sikaflex can be used to seal horizontal expansion joints. It’s a great product because it remains permanently flexible, dries quickly, sticks to anything, is self-leveling, and highly resistant to weather conditions. You should apply Sikaflex when the temperature is between 40F-100F.
Should you fill concrete expansion joints?
The key is to use the proper sealer or filler depending on the intended purpose and what type of joint it is. Just remember that expansion joints should always be sealed and filled with a flexible joint sealer and never be epoxied or coated over.
Does a concrete driveway need expansion joints?
Concrete expands and contracts with changes in temperature and moisture. If not properly controlled, cracks can begin to appear. Placement of concrete control joints and expansion joints are crucial when designing and pouring concrete slabs and sidewalks.
How do you maintain expansion joints?
The expansion joint must not be subjected to torsion during handling and installation. The expansion joint should be stored on an even, solid surface in a clean and dry environment under a roof or other rainproof cover . Expansion joints should not be stacked on top of each other or knocked against each other.
What’s the purpose of an expansion joint?
Expansion Joints are a bellows type device. Expansion joints are used to absorb thermal expansion . They can also be used to absorb contraction in cryogenic lines and to reduce vibration in piping systems. Materials of construction for the bellows can be stainless steel or rubber or even a composite material.
Can a concrete structure be completely free of expansion joints & contraction joints?
For contraction joints, it may be possible to design a concrete structure without any contraction joints . ... If the structure is very slender (e.g. concrete carriageway), buckling may occur. Therefore, the structure has to be designed to take up these thermal stresses if expansion joints are not provided.
What is a cement control joint?
Contraction/Control Joints. Contraction/control joints are placed in concrete slabs to control random cracking . A fresh concrete mixture is a fluid, plastic mass that can be molded into virtually any shape, but as the material hardens there is a reduction in volume or shrinkage.
