Joint Filling

Control joints, or contraction joints, are cracks planned to occur during the shrinkage process.

Shrinkage is caused by temperature and moisture changes and happens regardless of the addition of control joints. When the concrete inevitably shrinks and cracks, we want to control where the crack takes place rather than it cracking randomly across the slab. Hence the name control joint. The vast majority

of shrinkage occurs within the first year of placement, especially the first 90 days, but the slab will continue to shrink for years which will cause the joint to widen over time. Joint filling should be put off

for as long as possible to allow the joint time to expand.

Without the control joint in place, a crack would appear randomly which would ruin the appearance of your slab. For clean, straight lines, control joints are the solution. But what happens if these joints aren't filled? By choosing to forgo joint filling, the joints will accumulate dirt, debris, and dust which can be difficult to clean. In facilities with food processing operations or medical facilities, they can become hazardous if they accumulate too much moisture which breeds bacteria. If the joint is left unfilled it can also be a place that heavy objects or heavy traffic can degrade and ravel the edge over time. Moisture mitigation is a huge issue in concrete, especially if the moisture is attacking through the joint. Unsealed joints can be an easy access point to moisture which impacts the adjacent slabs and even the base and sub-base.

After a joint is established, it needs time to activate as the slab cures. Ideally after 90 days, the joint should be filled or sealed. Joint filling is done the full depth of the joint, while sealing is only done over the surface level with a flexible material over a rod to help keep the proper shape of the joint. Filling requires a material with enough compressive strength to match the durability of the slab when subjected to heavy traffic. We use polyurea to ensure strength, durability, and quality joint filling. Joint filling is ideal for hard-wheeled traffic while sealing can be a fine alternative in lower-trafficked areas.