Why do concrete have cracks after several load is applied?

Chemical Reactions The cause of cracking is the expansive reactions between the aggregate and the alkalis in the cement paste. The chemical reaction occurs between active silica and alkalis, producing an alkali-silica gel as a by-product.

What are the reasons for cracks and how do you reduce the cracks in concrete?

Concrete expands and shrinks with changes in moisture and temperature. The overall tendency is to shrink. Shrinkage is the main cause of cracks, when concrete hardens it evaporates the excess water and thus shrinks, so lesser the water content, lesser is the shrinkage. Cracking shrinkage in slabs is ½ inch per 100 ft.

What does a crack in the slab mean?

1) Hairline Cracks They are primarily caused by the concrete settling while it cures. If a hairline crack in slab foundation is deep, it can lead to wider, more severe cracking inside the slab over time.

Why do hairline cracks appear in concrete?

Most structural cracks on concrete surfaces form as a result of pressure and stress. However, hairline cracks can also occur as a result of shrinkage from heat. As the structure cools, it will shrink, and this, in turn, causes hairline cracks to form.

Why do cracks occur in concrete?

A piece of concrete in the open air usually shrinks during hardening. This shrinkage is due to the evaporation of part of the water contained in the concrete. Cracking occurs when shrinkage forces become greater than the strength of the concrete.

What factors cause concrete cracking?

There are several causes of cracks in concrete. Cracks caused before hardening are due to constructional movement, settlement shrinkage, and setting shrinkage. Cracks caused after hardening are due to chemical reactions, physical movement, thermal changes, stress concentrations, structural design, and accidents.

What causes cracks on concrete floors?

Shrinkage is a main cause of cracking. As concrete hardens and dries it shrinks. This is due to the evaporation of excess mixing water. The wetter or soupier the concrete mix, the greater the shrinkage will be.

Should I worry about cracks in my concrete floor?

Generally, cracks in your floor are nothing to worry yourself over. The only time that you might be concerned is if the cracks start changing vertically, suggesting that there is some settling happening.

Are hairline cracks in slab normal?

Hairline cracks in a concrete slab are rarely a cause for concern. They can be controlled, but not eliminated. A crack in a slab of 1/8 inch or less is typically a normal shrinkage crack and not a cause for concern.

How do you treat hairline cracks in concrete?

You can repair hairline cracks in concrete with a grout made of Portland cement and water. Add just enough water to the cement to form a thick paste. Moisten the old concrete along the hairline crack with water for several hours before adding the grout.