Concrete is placed into a form in a wet condition. Through a process called hydration, the water in the mix makes the cement harden. Water is released during hydration, causing the concrete mass to shrink. In fact, on average the concrete shrinks dimensionally about 1/16 of an inch in ten feet (0.4 centimeters in 3 meters). Depending on the shape, size, and other factors, any concrete mass may visibly show cracking due to shrinkage.
Generally, concrete shrinkage and cracking is minimized by reducing the water in the concrete mix, protecting the fresh concrete during the first seven days from excessive temperatures and water evaporation, and reinforcing it. Note that reinforcing does not stop concrete from cracking; it keeps small cracks from getting bigger.
Anyone who thinks concrete is inferior because it has cracked does not understand that all concrete cracks because it shrinks as it hardens. The best strategy is to figure out how to minimize cracking and control where it cracks บ้านมือสอง ราคาถูก since it is going to anyway.
Talk to your home builder about how he intends to control or reduce cracking of concrete in your new home. Here are six ways:
o In concrete slabs, consider using "fiber mesh" or installing wire (or bar) reinforcing horizontally in the middle third (between the top and bottom).
o Reduce the amount of water in the concrete mixture and/or increase the cement content.
o Protect fresh concrete from excessive wind, sun, and freezing for the first seven days.
o Use water curing methods or apply a liquid membrane curing compound.
o Make sure the ground or subgrade under concrete is firm and relatively dry.
o Weaken the concrete along specific lines with some type of control joint so it cracks where you want it to.
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