Cracks in concrete are caused by a number of factors including: temperature cycles, changes in moisture levels, stress loads (such as heavy traffic or heavy objects), ground or building movement, the dehydration process of the concrete slab when it is curing, or poorly placed contraction joints.

Some cracking is typical in all concrete floors. Most cracking is the result of slab restraint. In ambient conditions, slabs will expand and contract as the ambient temperature and relative humidity rises and falls. When concrete slabs cannot move freely because of embedded restraints or subgrade friction, they crack. Other floor slab cracking is typically caused by overloading the slab or failure of the sub grade to adequately support the slab.

The repair of cracks may be necessary to improve the appearance or durability of the structure. Before carrying out any repair, it is important that the cause of the crack is understood and, if necessary, rectified. In general, cracks that have developed & are no longer moving can be repaired.

• If a crack is no longer moving - then it can be repaired & sealed prior to applying the new resin flooring system. The best procedure & materials for doing this depends on the width, depth & length of the crack. It is likely that the surface will need opening / cutting out to remove any loose materials & then it can be either 'surface sealed' with a fine epoxy mortar which is pressed into the cracks. Alternatively, the crack repairs can be achieved by structural bonding with low pressure epoxy resin injection products.
• If a crack is moving - for example on a daily basis due to temperature changes, filling the crack will simply result in another crack forming adjacent to the original location. If the cracks are still likely to be subject to future movement, then they should normally be treated as joints, cut square, brought through the floor finish & sealed with an appropriate floor joint sealant. Most cracks in factory & warehouse floors occur in close proximity to the joints in the concrete surface.

• Dairy production facilities
• Meat and fish processing plants
• Fruit, vegetable, and berry processing facilities
• Sauce and canned food manufacturing plants
• Bakery and confectionery production facilities
• Alcoholic and non-alcoholic beverage production and bottling facilities
• Pharmaceutical production facilities and warehouses
• Chemical storage facilities, including storage of hazardous and explosive substances
• Refrigerated storage facilities and freezer rooms

• Dairy production facilities
• Meat and fish processing plants
• Fruit, vegetable, and berry processing facilities
• Sauce and canned food manufacturing plants
• Bakery and confectionery production facilities
• Alcoholic and non-alcoholic beverage production and bottling facilities
• Pharmaceutical production facilities and warehouses
• Chemical storage facilities, including storage of hazardous and explosive substances
• Refrigerated storage facilities and freezer rooms

• Dairy production facilities
• Meat and fish processing plants
• Fruit, vegetable, and berry processing facilities
• Sauce and canned food manufacturing plants
• Bakery and confectionery production facilities
• Alcoholic and non-alcoholic beverage production and bottling facilities
• Pharmaceutical production facilities and warehouses
• Chemical storage facilities, including storage of hazardous and explosive substances
• Refrigerated storage facilities and freezer rooms

Many flooring repairs are related to the breakdown of joints in the concrete slab. Joints are common throughout the warehouse floor & represent unavoidable discontinuities in any factory or warehouse floor surface.

The most common types of joints formed in commercial warehouse floors are contraction, expansion, and construction joints.

1. Contraction joints

While drying, hardened concrete will shrink by about 1.6 mm per 3 metres of length. To accommodate this shrinkage and regulate the location of crack formation, joints are placed at regular intervals throughout the floor.

These joints are usually sawed into the newly hardened concrete surface around 4-12 hours after the concrete is laid; however, the longer sawing is delayed the higher the potential for cracks to develop and establish themselves.

Industrial concrete floors are subject to heavy floor load – as a heavy vehicle approaches a joint, the slab will deflect slightly. As it deflects next to a joint, the top edge will crush against the concrete on the other side of the joint (eventually degrading the joints).

To help prevent this, the two sides of the joint may be purposely “tied” together vertically so that one side can't deflect independently. However, floor joints are still the greatest source of problems in industrial and warehouse floors.

This is because without adequate protection the concrete joint edges or 'arrises' are vulnerable to the passing of heavy, hard-wheeled traffic which cause 'spalling' and the joint arrises begin to deteriorate and erode quickly.

If the damage to the floor joints becomes severe and widens, the uneven surface can cause significant damage to the Materials Handling Equipment, tire, resulting in increased maintenance costs and can even lead to health complaints from the operators e.g. because of fatigue and injuries from jolts etc.

It is therefore essential that even relatively minor concrete floor joints are repaired in order to avoid more significant damage and repair disruption.

There are two general concrete floor joint repair options depending on the damage severity.

Mildly damaged floor joints can be repaired by:

• Re-cutting the joint to create smooth & stable edges.
• Removing existing damaged joint filler.
• Replacing the joint with a suitable semi-rigid joint filler & sealant which still allows for some movement in the floor.
• Shaving the joint filler flush with the concrete floor to allow wheeled traffic to move across the joint smoothly.

Severely damaged floor joints, however, are repaired by:

• Removing all damaged or 'spalled' concrete from the joint.
• Squaring-off the damaged concrete edges so that repairs are not feather-edged.
• Replacing the material removed with a durable concrete floor repair mortar.
• Re-cutting the joint so that the original joint position is 'honoured'.
• Replacing the joint with a suitable semi-rigid joint filler & sealant which still allows for some movement in the floor.
• Shaving the joint filler flush with the concrete floor to allow wheeled traffic to move across the joint smoothly.

Industrial floor finishes are constructed to be dense and very abrasion resistant, thus resistant to pitting. Pitting is the formation of widespread, very small holes close to each other and the floor finish has the appearance of coarse sand paper.

Pitting is the wearing out of the finish, though less likely due to sliding friction and more likely the consequence of residue or items on the floor crushing under traffic.

Premature finish wear can be the result of poor finish quality. If the slab contractor did not deliver a dense durable finish it may wear unfavorably compared with similar floors. Sometimes concrete carbonation, the reaction between wet concrete and carbon dioxide to form a chalky soft finish, is the culprit. Acids, in any form, but especially low concentrations permitted to remain in place or repeatedly wet and dry can weaken good quality concrete.

Housekeeping is an important role in maintaining the service life of a concrete finish. Overly aggressive cleansers can weaken cement paste. When cleaning the floor, the residue needs to be retrieved from the finish. Floor scrubbers are often operated so quickly that the floor is simply wet and scrubbed, with the residue remaining behind on the floor, instead of collected in the on-board tank of the scrubber. Dirty floors can lead to pitted floors.