Frequently Asked Questions

Quick Mix Concrete / Frequently Asked Questions

What is a Flowable Fill ready mix?

  • Flowable fill is a self-compacting low strength material with a flowable consistency that is used as an economical fill or backfill material as an alternative to compacted granular fill. Flowable fill is not concrete.


What is a concrete retarder?

  • Concrete retarders are additives that slow down the chemical process of hydration so that the concrete remains workable for a longer period of time (typically used in hot weather).


What is a ready mix accelerator?

  • Accelerators make concrete set faster, also known as increasing the rate of hydration. At the same time, they promote strength development so it happens earlier in the set time of a slab Typically used in cold weather or when strength tests need to be met in a short period of time.


What are the types of concrete accelerators?

  • Calcium Chloride (1% & 2%) & Non-Chloride Accelerator (NCA) (1% & 2%) are the most commonly used types in ready mix concrete.


How to determine which accelerator to use?

  • If steel or rebar is being used NonChloride Accelerator should be used. Calcium chloride causes corrosion that leads to premature failure. NCA has become the standard and is always safe to use.


How many 80 pound bags of concrete is 1 yard?

  • 45 bags


How many 60 pound bags of concrete is 1 yard?

  • 60 bags


How much does 1 yard of concrete weigh?

  • Wet concrete can weigh as much as 4,000 lbs +. Dry will be about 3,6000 lbs. Mix design and psi can drastically change the weight.


How many wheelbarrows does it take to unload 1 yard of concrete?

  • Now, this is a load question because it depends on how much the pusher can push and the strength of the wheelbarrow. Generally speaking, we have noticed it takes 19-24 wheelbarrow trips per yard of ready mix.


How long are the Quick Mix Concrete truck’s chutes?

  • 12 feet.


What is the height & width clearance for Quick Mix trucks?

  • Height: 9 ft 6in Width: 8 ft 0 in. Note this spec could vary from truck to truck and is with the funnel in the travel position.


Will sugar affect the ready mix concrete?

  • Absolutely! It all depends on the amount used. Too much will cause the concrete not to set up or cure. Below the too much point it will act as a retarder! Also, depending on the amount used it can increase the final strength! What are these amounts? Well, we don’t know the exact and nor do we recommend using it.


What is 1 cubic yard of ready mix concrete and how to calculate?

  • Measure the area in feet. Multiply length by width, and then by thickness. Divide the resulting number by 27 to find cubic yards.
  • Additional information:
    • 1 cubic yard is 27 cubic feet.
    • One yard of concrete, also known as a cubic yard, covers: 81 square feet at 4 inches thick. 65 square feet at 5 inches thick. 54 square feet at 6 inches thick
    • Concrete Calculator


What is the difference between Interior and Exterior mix?

  • Indoor concrete is generally meant for foot traffic and should provide a smooth look. Indoor concrete is typically polished down to a nice sheen and finished to allow for good grip and a continued shine. Interior concrete is typically not exposed to natural changes of the environment and often does not require any air entrainment as it has less of a tendency to crack than exterior concrete.
  • Finishing exterior concrete too early (before the excess water has time to rise to the top) can trap the bleed water, setting the stage for other surface problems.
  • Outdoor concrete is often rougher since it is often meant for creating grip for car traffic and pedestrians, reducing the chances of any slipping or falling.


What is ready mix slump and how is it measured?

  • Slump is the measure of concrete consistency and fluidity. It shows the flow and overall workability of freshly mixed concrete. Simply put, the higher the slump, the more fluid the mix. Four-inch (4”) slump is very common with normal weight concrete and is good for pumping. Slumps that are above mix design can cause reduced strength, durability, and permeability of the concrete. Admixtures can be used instead of water to achieve higher slumps and can maintain the quality of your concrete.
  • Slump is tested with a slump cone (aka Abrams cone). Simply put the ready mix concrete is packed into the cone and then the cone is slowly lifted away from the ready mix. The concrete slump is measured by measuring the distance from the top of the slumped concrete to the top of the slump cone.


What is a ready mix concrete line pump?

  • A pump that moves concrete to an inaccessible location. They can be mounted to a truck bed or tailgate, trailer, or a whole truck. They can save time, money, and energy. They do require a special mix to ensure the ready mix will flow.


What is the difference between line pump mix and the standard mix?

  • The ideal ready mix concrete for pumping typically contains air-entraining agents, a little extra sand (compared to standard mix), fly ash, and a smaller aggregate blend.


When should a line pump be used?

  • Line pumps are generally used to reach projects that are in “hard to reach” places (ie: basements, backyards, tight spaces in between houses or buildings and areas on a steep incline). Line pumps are a convenient way to get your concrete exactly where you need it.


What are ready mix concrete additives and when should they be used?

  • There are hundreds of different additives. Here are the most common:
    • Fiber: increases the concrete’s durability. It reduces crack growth and increases impact strength. Fiber-reinforced concrete improves resistance against freezing and thawing.
    • Retarder: Slows down set time. Typically used in warm weather.
    • Accelerators: Speeds up set time in cold weather or when strength is need quicker.
    • Water Reducer: Significantly decrease the amount of water needed in a mix design.
    • Flowable fill is defined by the American Concrete Institute (ACI) as a self-compacting cementitious material that is in a flowable state at placement and has a compressive strength of 8.3 MPa (1,200 lb/in2) or less at 28 days. Generally used in utilities or in construction where the material will be removed.


What does PSI stand for?

  • Pounds per square inch (psi) measures the compressive strength of concrete. A higher psi means a given concrete mixture is stronger, so it is usually more expensive. But these stronger concrete are also more durable, meaning they last longer. Most common are between 3,000 & 4,500 psi


How do you determine the PSI you need for your project?

  • An engineer would need to provide a definite answer, but here are general concrete strength (PSI) for common structures:
    • Concrete footings and slabs on grade typically require a concrete of 3,500 to 4,000 psi.
    • Suspended slabs, beams, and girders (as often found in bridges) require 3,500 to 5,000 psi
    • Traditional concrete walls and columns tend to range from 3,000 to 5,000 psi.
    • The residential workhorse of concrete, 3,000 PSI can be used for driveways, patios and sidewalks if you aren’t expecting to drive or park heavy equipment on it.
    • If heavy vehicles such as RVs are being placed on your driveway or parking area 3500 PSI should be used.


What do I need to know when ordering concrete?

  • Basics: Name, Phone Number, Location, & Payment
  • Amount needed in cubic yards. It is a good idea to order 4-10% more than need for waste and over excavation.
  • The PSI
  • Where you plan on unloading the truck. It is highly recommended that the truck stays on a hard surface.