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Pouring concrete is one of the most important home improvements to do right the first time because it is not something you want to do twice. Most consumers hire a professional, licensed concrete contractor to add concrete to their property because professionals are usually best equipped to know how much of what kind of concrete is needed and will be responsible for having it properly delivered and finished.
There may be times a homeowner may choose to have the concrete delivered directly, perhaps to pay the concrete delivery company separately from the contractor, or because he is confident he can finish it himself or with help from other non professionals. It is important that the site is prepared before the concrete truck arrives, including all forms set and the ground properly leveled and moistened, if necessary. Concrete delivery companies may schedule several pours in a row and will charge extra if the driver has to wait idle on any site because it is not ready for the pour.
If concrete is to be poured where the delivery truck cannot reach, the concrete will need to be carried by wheelbarrow or pumped by an independent concrete pumping company if it is too much to wheelbarrow, this is usually coordinated by the contractor or the concrete delivery company.
The proportion of mix to water must be right in order for concrete to be strong enough for its application. Foundations require less water than flat slabs, for instance. Concrete does not "dry" but cures. Usually, the more slowly concrete cures the stronger and less likely it will be to crack. Water must be sprayed on poured concrete several times a day for up to a week to make sure it does not cure too fast. It is also important the soil underneath poured concrete is wet so the dry soil does not absorb water from the concrete, causing it to cure too fast.
No matter how well concrete is poured no contractor can guarantee concrete will never crack. Tiny surface hairline cracks are not uncommon and will not affect strength or performance of finished concrete.
New concrete driveways, sidewalks and exterior patio surfaces if done incorrectly will peel shortly after the first winter; random jagged cracks scar the surface, and puddles of water often form in the middle of a slab. Make sure your builder and concrete mason have a complete grasp and understanding of how to professionally install exterior concrete.
Concrete is an artificial man-made rock comprised in its most basic form of Portland cement, gravel, sand and water. It is not uncommon for concrete to also contain smaller amounts of fly ash, silica fume and even ground slag. The Portland cement powder ingredient is the basic glue that holds the sand, gravel and other components together.
If you want strong concrete that will stand the test of time, you first need to make sure you have sufficient cement in the mix. The industry uses both strength measurements in pounds per square inch (psi) and volumetric measurements to communicate strength. For example, it is recommended that the minimum strength for exterior slabs be 4,000 psi or a six-bag mix.
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