Joining Concrete Floor Slabs

The construction joint is used where we want to do a pour a slab in sections but we still want the slab to look and act as if it one slab.

Joining concrete floor slabs.

When using joint groove for contraction joints the joint should be a minimum depth of thickness of the slab. Expansion joints are spaces between concrete slabs that are filled with a flexible sealant like silicone or urethane. Just make sure your pouring atleast 4 thick 3000 psi on good compacted ground and allow it to cure properly. In maine where i ve been working with concrete for 40 years now and this website is where i can share with you all the knowledge and wisdom i ve gained from installing all kinds of decorative concrete concrete floors concrete overlays stained concrete and also fixing cracked or spalled concrete.

Hi i am mike day owner of day s concrete floors inc. Concrete undergoes expansion due to high temperature when in a confined boundary which leads to cracks. While it sounds complicated the proces to join two concrete slabs is easy but might take a few attempts to get it right. Dry cut joints should be made between 1 to 4 hours after completion of finishing.

Expansion joints are placed in concrete to prevent expansive cracks formed due to temperature change. Keyed joints are not recommended for industrial floors. Joining slabs involves creating a joint that both structurally connects the slabs and provides a flexural point to accomodate how the different ages of the slab will respond to climate and stress. This article emphases on need of expansion.

Your new slab once 100 cured and properly doweled should move with the old one. It is a good option if you need to fill a large area with something thick that will last a long time. Expansion joints are provided in slabs pavements buildings bridges sidewalks railway tracks piping systems ships and other structures. Saw cut joints should be done within 4 to 12 hours after the concrete has been finished.

Concrete s high compressive strength and hardness make the concrete useful for flooring applications in many industries. This type of concrete is stronger but less dense so you can safely pour a large slab onto existing concrete. Coarse concrete has gravel or larger stones as an additive. If we were to just pour the two slab sections against each other without joining them together there is a chance that the movement of the ground could lift one side of the join and not the other again.

Contraction control joints are placed in concrete slabs to control random cracking. Square and rectangular dowels and for diamond shaped load plates are provided in aci 302 1r 04 guide for concrete floor and slab construction or aci 360r 06 design of slabs on ground. Sizes and spacing for round. However concrete moves during expansion and shrinkage due to which the structural elements shift slightly.