What is concrete?
Concrete is a mixture
of cement, sand and aggregate mixed in certain proportions determined by the
strength required. When water is added to the mixture a chemical reaction
occurs by which concrete becomes solid. Water cement ratio (amount of water per
bags of cement) is very important. If more water is added concrete losses its
compressive strength. However, add to little and the concrete is not workable.
Additional compounds usually known as admixtures are also added to concrete
mixture to improve the workability of the concrete. Concrete is strong in compression but weaker
in tension. Therefore, to improve its tensile strength steel reinforcement is
added.
What causes cracks?
Cracks in concrete are
inevitable. Although good workmanship and quality control can avoid disasters.
However, they cannot prevent cracks from developing over period of time. Cracks
in the concrete are a result of many different reasons. Few of them can be!
1. SHRINKAGE CRACKS
Concrete in its
plastic state contains water, when water evaporates during curing of concrete,
it shrinks and stresses develop. To release these stresses cracks develop in
concrete. These cracks can develop anywhere on concrete which can be unsightly.
Therefore, a good practise is to construct control joints (not expansion
joints) at regular intervals to control where the cracks should develop so that
they don't appear ugly.
2. EXPANSION CRACKS
Concrete like any
other material expands and contracts as per variations in temperature. When
concrete expands and pushes against the adjoining material, stresses develop
resulting in development of cracks. Expansion joints are required at regular
distances and various other locations to prevent these cracks.
3. CRACKS CAUSED BY
HEAVING
Ground conditions also
result in development of cracks in the concrete. Certain types of soils expands
when wet and contracts when dry. Furthermore, frost will make the soil to
expand and while thawing the soil contracts. This cycle of expansion and
contraction causes concrete to crack.
4. SETTLEMENT OF
GROUND
All buildings settle
little bit after getting constructed. If the ground underneath was not
compacted properly, differential or irregular settlement can occur resulting in
development of cracks.
5. OVERLOADING
Concrete is designed to
take certain amount of load. If it is loaded beyond that limit cracks might
appear. Furthermore, the ground below the concrete may not be compacted
properly or is wet, making it to settle under load and as a result cracking the
concrete.
6. PREMATURE DRYING
If the concrete dries
to quickly then the crazing cracks appear on the surface.
At RK Home Inspections we are available 7 days a week and we serve entire GTA Home Inspection Toronto, Home Inspection Mississauga, Home Inspection Brampton, Home Inspection Vaughan, Home Inspection GTA, Home Inspection Markham, Home Inspection Milton
Find us on google places / maps Home Inspection Mississauga, Home Inspector Mississauga, Mississauga Home Inspection
No comments:
Post a Comment