Published:
December 20, 2022
It's very common to have questions and concerns about concrete. Here are some basic ones that we get a lot, but of course if you have other questions or would like something explained more in-depth, feel free to give us a shout.
Concrete is a mixture of 6 main materials: air, Portland cement, water, fine aggregates (sand and rock dust), coarse aggregates (rock gravel), and chemicals to enhance the mixture properties. Concrete is one of the oldest building products known to man because of its strength, resilience, and versatility.
Cement is one of many ingredients in concrete - it's basically the 'glue' that binds the different components together. When cement powder is mixed with water, a chemical reaction occurs that makes it harden. There are different grades of cement for different uses and purposes.
Unlike gravel, asphalt, and many other materials, concrete isn't sold by weight, it's sold by volume - the cubic yard. A cubic yard is exactly what is sounds like: a cube measuring a yard (or 3 feet) on each side.
Concrete is delivered in trucks that typically hold up to 10 cubic yards. The truck rotates to keep the material well-mixed, otherwise the aggregates would all sink to the bottom. The rotation does not keep the material from setting-up or hardening - it will do that with time no matter what, even inside the truck. Once the truck arrives to the project, the concrete's poured down a 16' long chute.
The concrete material can also be pumped to reach areas too far or inaccessible for the truck. A regular pump just uses a hose, but some locations require a boom pump (pictured).
Concrete can be made in different strengths depending on the grade of components in the mix. The strength and durability is measured in PSI, or pounds per square inch. Things like sidewalks and driveways are usually around 3,000 PSI, while columns and streets are upwards of 5,000 PSI.
Additives like fibers, steel rebar, and wire mesh can also help increase the strength. There are varying types and sizes of all of these for different uses.
The ratio of ingredients also affects the strength. The consistency is mainly determined by the water to cement ratio and is called the 'slump'. More water increases the slump and decreases strength, and also results in more shrinkage and cracking. Because of this, chemicals are usually used instead to get a more fluid and workable mixture if needed.
All concrete can crack, and eventually will given enough time. With that said, using the correct mix and applying it properly can minimize and stall the appearance of cracks.
You can also saw-cut or tool in joints. These joints not only give the concrete room to expand with the temperature, they help guide cracking in a more controlled manner.
The cost of a concrete project varies greatly due to all the variables that go into pricing. There's a minimum cost involved just to get the crew and equipment to the job site, as well as minimum material orders from the concrete plant.
From there, the other main factors influencing price are: the quantity of material, type of material, required crew size and length of time to form, pour, and finish the concrete, any demo or removal, and any additions or specializations to the material or application.
We provide free, no-obligation price quotes and would love to help out with your project. We also give recommendations on how to keep your budget low and get the most bang for your buck - we treat every project as if it was our own home. Call or text now: 858-345-0305.