For most DIY concrete projects, the amount needed to complete the job is measured in cubic yards. The standard concrete measuring device usually available is a wheelbarrow. We have researched a simple method you can use to convert the number of wheelbarrow loads necessary to accomplish any concrete job.
The wheelbarrow capacity will determine how many loads it takes to complete 1 cubic yard or 27 cubic feet of concrete. Generally, a 3 cubic foot wheelbarrow requires 9 loads (3x9=27).
The article includes ways to calculate the amount of concrete you need based on its weight as well as the number of loads it takes to complete specific projects. Please keep reading to learn more!
The Conversion Factor
One yard is equal to 3 feet, therefore, 1 cubic yard is equal to 27 cubic feet. This is the three-dimensional standard of measurement we'll use moving forward with this discussion.
How To Determine The Capacity Of Your Wheelbarrow: Simplified!
Wheelbarrows are an excellent way to transport different materials of considerable weight from one area of your property to another. They are available in different capacities, from a typical garden variety that can hold 2 to 3 cubic feet to a contractor-grade model which can carry up to 6 cubic feet of material.
Usually, the capacity is specified on a sticker on the wheelbarrow's side or embossed on the wheelbarrow's metal. However, if you are unsure of its actual limit, there is a simple way to determine its allowable cargo volume.
A cubic foot contains 7.5 gallons of water. Fill your wheelbarrow about 3/4 of its capacity with water. If it can contain 15 gallons, this is the equivalent of 2 cubic feet. If it can hold 22.5 gallons below the rim, then its capacity is equal to 3 cubic feet.
Once you've established the capacity, you can now calculate the number of loads needed for 27 cubic feet or 1 cubic yard of wet concrete. Simply divide 27 by the wheelbarrow's allowable volume.
To illustrate, 27 divided by 3, which is the wheelbarrow's capacity in cubic feet, equals 9, which is the number of loads needed.
If you own a deep tray wheelbarrow that can carry 6 cubic feet (45 gallons) of material, then 27 divided by 6 equals 4.5 loads.
Knowing the volume capacity of your wheelbarrow gives you the advantage of calculating the number of trips necessary to transport gravel from one point to another to undertake and complete a project.
This reference becomes important if you are working on a comparatively large area to pave or pour concrete. The number of loads and consequent trips would factor out where to strategically place or position the concrete load.
How Much Does 1 Cubic Yard Or 27 Cubic Feet Of Concrete Weigh?
How much material is actually needed for a cubic yard or 27 cubic feet of concrete?
The standard weight for dry concrete is 3,600 pounds and about 4,050 when mixed with water.
Premixed concrete comes in bags containing 90, 80, and 60 and other weights in pounds. Simply divide the total dry weight (3,600 pounds) by the weight of the bag you purchased. You will need:
- Forty 90-pound bags,
- Forty-five 80-pound bags,
- or sixty 60-pound bags to complete 27 cubic feet of concrete.
The weight of the concrete material will give you a more accurate or precise estimate of just how many bags are needed to accomplish the task.
This will prevent a lack or excess of usable concrete. However, it is advisable to give an allowance in terms of volume to replace any spills, fill necessary gaps or flatten out uneven surfaces.
How To Determine The Amount Of Material Needed For Specific Projects
The following section gives a few illustrations of the practical application of the above conversions and measurements.
Example 1: A 12-foot long, 4-foot wide walkway 3 inches thick.
- First, multiply the length by the width to get the square footage: 12 x 4 = 48 square feet
- Convert the thickness from inches to feet: 3/12 = 0.25 feet
- Multiply the square footage by the thickness to get the cubic feet measurement: 48 x 0.25 = 12 cubic feet
We have established that 27 cubic feet of dry concrete weighs 3,600 pounds (3,600 pounds divided by 27 = 133.3 the weight of 1 cubic foot of concrete).
Since the project totals 12 cubic feet, you need 133.3 x 12 = 1,600 pounds of premixed dry concrete or twenty 80-pound bags (1,600/80 = 20).
Finally, it would take four loads of wet concrete for a wheelbarrow with a capacity of 3 cubic feet (4 loads x 3 cubic feet = 12 cubic feet).
Example 2: An 8 by 8 foot patio, 4 inches thick
- The square footage: 8 x 8 = 64 square feet
- The thickness from inches to feet: 4/12 = 0.33 feet
- The cubic feet measurement: 64 x 0.33 = 21.33 cubic feet
- The weight and number of 80-pound bags needed: 21.33 cubic feet x 133.3 pounds per cubic foot=2,843.73 pounds of dry concrete or thirty-five-and-a-half 80-pound bags (2,843.73/80 = 35.54)
It would take seven loads of a wheelbarrow with a capacity of 3 cubic feet (21.33/3 = 7.11)
Example 3: 4 concrete posts, 6 by 6 inches, 6 feet high
- First, convert the inches into feet: 6/12 = 0.5 feet
- Multiply both sides of the post: 0.5 x 0.5 = 0.25 feet
- Multiply it further with the height to compute the cubic feet measurement: 0.25 x 6 = 1.5 cubic feet
Since you need four posts, the total becomes 6 cubic feet
The weight and number of 80-pound bags needed: 6 cubic feet x 133.3 pounds per cubic foot = 799.8 pounds of premixed concrete or ten 80- pound bags.
It would only take two loads of a wheelbarrow with a capacity of 3 cubic feet
To recap and summarize the key points:
- The standard weight of 27 cubic feet or 1 cubic yard of dry premixed concrete is 3,600 pounds
- If we divide 3,600 pounds by 27, we get 133.3 pounds which is the weight of one cubic foot of dry concrete
- To get the square area, simply multiply the length by the width of the surface. A 10 feet long by 8 feet wide equals an area of 80 square feet
- Convert the thickness from inches to feet by dividing it by 12. 3 inches divided by 12 inches per foot equals a thickness of 0.25 feet
- To compute the cubic feet, multiply the area in square feet by the thickness. 80 square feet x 0.25 feet = 20 cubic feet
- Multiply the total cubic feet by the weight of 1 cubic foot of concrete to calculate the amount you need. (20 cubic feet x 133.3 pounds = 2,666 pounds).
- Divide the total weight by the weight of the bag you have, say 80-pound. 2,666 divided by 80 = 33.325 or approximately thirty-three-and-a-half bags of concrete
- Finally, divide the total cubic feet by the wheelbarrow capacity to get the number of necessary loads. (20 cubic feet divided by 3 cubic feet = 6.66) or seven loads.
How Much Water Should I Add To Concrete Mix
Using premixed concrete bags is convenient and more reliable since the proportion of cement to aggregates has been predetermined more accurately in terms of structural standards.
The right amount of water introduced into the mix will ultimately determine the strength and durability of the compound. With premixed concrete, you will simply have to follow the instructions in the bag and confidently work on any project.
However, what is the ratio of the materials if you decide to prepare the mix yourself? Concrete is composed of cement, sand, gravel, and water; a 1:2:3:0.5 is the standard proportion for general all-around purposes.
The simplest way to get the mix right is to use a pail or bucket to measure each ingredient accurately. Use 1 part cement, 2 parts sand, and 3 parts concrete and premix them until the components are distributed evenly before adding the water.
Take note that the 0.5 ratio of water is relative only to the amount of cement and does not include the sand and gravel components. Add the water gradually, and mix the compound thoroughly until a uniform texture is achieved.
Use the least amount of water that will allow a workable mix since the amount of hydration is the most important determining factor of the concrete's strength and integrity.
The 1 part cement to 0.5 part water ratio is the highest proportion structurally advisable. It is actually ideal for lessening the amount of water as long as the mixture is not too heavy to work with.
If you are working on a large surface area, measuring the components with buckets might be too labor-intensive. In this case, a 27 cubic foot mix would need approximately five 90-pound bags of cement, 10 cubic feet of sand, and 15 cubic feet of gravel, with around 27 gallons of water.
The capacity of the wheelbarrow determines the number of loads necessary to accumulate a cubic yard or 27 cubic feet of concrete. Simply divide 27 by the volume that you can accommodate in your transporter. We hope the article clarifies your question and helps you determine the necessary measurements to complete the task.
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