When you hear someone reference concrete PSI (pounds per square inch), basically they are talking about how strong the concrete becomes once it has cured. The higher the psi rating, the more compressive force it can handle. What does that mean? Imagine you are building two parking pads. One pad for a 3000 pound Honda Civic and one for a 30,000 pound 40’ RV. Obviously, the RV will be putting a much higher compressive force on the concrete than the Civic. The RV parking pad will require the concrete to cure at a higher strength. And that strength is achieved by creating a higher PSI mix of concrete.
What creates a higher PSI concrete mix? Great question. Concrete is a mixture of sand, aggregate (stone), water, air, and cement. Have you ever heard someone refer to a driveway as being a “cement driveway”? To get picky, it is actually a concrete driveway, cement is simply part of the mixture that makes the concrete, but I digress….The more cement added to the mix, the higher the PSI rating of the concrete once it has cured. For example, a traditional 3000 PSI concrete mix contains 5 sacks of cement. To achieve 4000 PSI it takes 6 sacks of cement. The added cement is also why higher PSI mixes are more expensive. They require more raw materials, increasing the cost. And while I am thinking about it, our trucks aren’t called “cement trucks”, technically they are “concrete trucks”, remember, cement is just part of the mixture. But I digress again……
So you are probably asking yourself. Self, how do I know what PSI mixture I need for my project? If you are using a contractor to finish the concrete, they will be able to spec this out for you so you don’t have to worry much about it. However, it never hurts to be an educated consumer. Don’t hesitate to ask your contractor what PSI they are using and why they are using it!
At Rocket Concrete we can supply a wide range of concrete mixes. The three most common are; 3000 PSI, 3500 PSI, and 4000 PSI. If you are handling the project on your own, here are some general rules of thumb.
3000 PSI concrete is widely used in residential applications such as sidewalks, patios, and driveways if you aren’t expecting to drive or park heavy equipment on it.
3500 PSI is less common in sidewalks and patios. It is more often used for foundation footings, slabs, or driveways/parking areas for heavy vehicles like an RV.
4000 PSI is a great option for serious home workshops. For instance, if you are planning on installing a car lift, or have heavy equipment secured to the slab. Most commonly this is used for factory and warehousing applications.
Remember, PSI is a measure of how strong the concrete will be, cement is what makes concrete strong, adding more cement makes concrete stronger. Make sure you are using a concrete strong enough for your application. And most importantly, it isn’t a “cement driveway”, if it were your driveway would be a powdered mess.
Call Rocket Concrete today at 980-281-3131 to schedule a ready-mix concrete delivery. We proudly deliver to all areas of Charlotte, North Carolina.
