Density of concrete (weight per unit volume) or weight of concrete per cubic foot in fps system of units is 150 pounds per cubic foot. That means a block of concrete with dimensions of 1’x1’x1’ (length x width x height) comes out as 150 pounds.
When it comes to concrete weight, a lot of homeowners are searching for terms like how heavy is concrete per cubic foot, or how much 1 foot by 1 foot of concrete weigh. While you’re working on a demolition project, you’ll want to know the weight of broken concrete per cubic foot; so you can order the right size of dumpster for your project.
Same stands true while you’re ordering the amount of trucking for your project. Similarly, you might want to know the weight of concrete per cubic foot while you’re placing some precast member in your project and you want to determine the capacity of lifting crane or skid-steer loader.
Weight of concrete
Weight of concrete per cubic foot is different than weight of concrete per cubic yard or cubic meter. So, first you need to select the desired unit. Common units to know the weight of concrete (density) is imperial measurement unit, customary measurement system and metric system. Anyhow our today’s article will deal with weight of concrete per cubic foot or (weight of concrete per cft).
In my another article, I’ve explained the factors on which the weight of concrete depends.
Also Read
Weight of concrete – Density – Concrete Slab – Driveways
Some factors effecting weight of concrete includes, size of concrete member, grade of concrete, proportion or mix design, type of aggregate (normal or lightweight), type of cementations material (cement type or slag), type of reinforcement (rebar or fibers), compaction or densification of concrete (densely packed or loose), and mode of compaction (table vibrator, rodding, or no compaction).
Hence the weight of light-weight concrete will be different than normal weight concrete. Similarly, reinforced cement concrete will have different weight as compared with lean concrete.
To understand the weight of concrete, we also need to learn about the density of concrete.
The density of concrete depends on the factors like amount and gradation of aggregate (more fine aggregate will have more density than coarse aggregate concrete), water, and air in the mix (void-ratio). The density of normal concrete is 2400 kg/m3, 24 kN/m3 or 150 lbs per cubic foot. It is same as 4050 lbs per cubic yard.
In US both imperial and Customary measurements units are used to weigh concrete for different applications. In Imperial measurement system, the concrete weighs 150 lbs per cubic foot and the same in US customary measurement system is 2400 kg per cubic meter (2.4 kg/liter)
What is the weight of 1 cubic foot of concrete?
Let’s take a 3000 psi concrete mix which is the 28 days cylindrical compressive strength of concrete. The mix ratio for a 3000 psi concrete is 1:3:3 (that means 1 part of cement, 3 parts of sand, and 3 parts of aggregate). Now if you take once cubic foot of concrete and divide the one cubic foot among different ingredients of concrete, you can determine the weight of different ingredients in 1 cft of concrete.
Here’s how we calculate:
Cement = 20 pounds
Sand = 57 pounds
Aggregate = 59 pounds
Water = 14 pounds (0.65 water cement ratio)
Now if you total all the weight it comes out as 150 pounds per cubic foot.
Using this thumb rule (1 cubic foot of concrete weighs 150 pounds) you can determine the weight of 2 cubic foot of concrete, 3 cubic foot of concrete, 4 cubic foot of concrete, and so on.
Let’s assume you have a concrete slab that you’re looking to demolish. The weight of a broken concrete slab will be less around 75 lbs (pounds) per cubic foot. That’s because when you collect a broken concrete in some bucket or a tool, it will have way less density than a solid concrete.
Weight of 2 cubic feet of concrete
Since the weight of concrete per cubic foot is 150 lbs, the weight of 2 cubic feet of concrete will be 2×150 = 300 lbs (pounds). That means a concrete of 2 foot width, 2 foot height, and 2 foot length will have a weight of 300 pounds (if it is a solid slab). For a broken concrete, the weight of 2 cubic feet will be 2×75 = 150 pounds.
Also Read: How much does a Cubic Yard of Concrete Weigh? (WET & DRY)
Weight of 3 cubic feet of concrete
Since the weight of concrete per cubic foot is 150 lbs, the weight of 3 cubic feet of concrete will be 3×150 = 450 lbs (pounds). That means a concrete of 3 foot width, 3 foot height, and 3 foot length will have a weight of 450 pounds (if it is a solid slab). For a broken concrete, the weight of 3 cubic feet will be 3×75 = 225 pounds.
Weight of 4 cubic feet of concrete
Since the weight of concrete per cubic foot is 150 lbs, the weight of 4 cubic feet of concrete will be 4×150 = 600 lbs (pounds). That means a concrete of 4 foot width, 4 foot height, and 4 foot length will have a weight of 600pounds (if it is a solid slab). For a broken concrete, the weight of 4 cubic feet will be 4×75 = 300 pounds.
Weight of 5 cubic feet of concrete
Since the weight of concrete per cubic foot is 150 lbs, the weight of 5 cubic feet of concrete will be 5×150 = 750 lbs (pounds). That means a concrete of 5 foot width, 5 foot height, and 5 foot length will have a weight of 750 pounds (if it is a solid slab). For a broken concrete, the weight of 5 cubic feet will be 5×75 = 375 pounds.
Also Read: Difference between Segregation and Bleeding in Concrete
Weight of 6 cubic feet of concrete
Since the weight of concrete per cubic foot is 150 lbs, the weight of 6 cubic feet of concrete will be 6×150 = 900 lbs (pounds). That means a concrete of 6 foot width, 6 foot height, and 6 foot length will have a weight of 900 pounds (if it is a solid slab). For a broken concrete, the weight of 6 cubic feet will be 6×75 = 450 pounds.
Weight of 7 cubic feet of concrete
Since the weight of concrete per cubic foot is 150 lbs, the weight of 7 cubic feet of concrete will be 7×150 = 1050 lbs (pounds). That means a concrete of 7 foot width, 7 foot height, and 7 foot length will have a weight of 1050 pounds (if it is a solid slab). For a broken concrete, the weight of 7 cubic feet will be 7×75 = 525 pounds.
Weight of 8 cubic feet of concrete
Since the weight of concrete per cubic foot is 150 lbs, the weight of 8 cubic feet of concrete will be 8×150 = 1200 lbs (pounds). That means a concrete of 8 foot width, 8 foot height, and 8 foot length will have a weight of 1200 pounds (if it is a solid slab). For a broken concrete, the weight of 8 cubic feet will be 8×75 = 600 pounds.
Weight of concrete per cubic yard
What does 1 yard of concrete weigh? Now as 1 cubic yard is 3 feet long by 3 feet wide by 3 feet deep, it equals to 27 cubic feet. That means 1 cubic yard is equal to 27 cubic feet. Now for 27 cubic feet of concrete weighs as 27×150 = 4050 pounds. So, 1 cubic yard of concrete weight around 4050 pounds. In reverse, we can divide 4050 by 27 to get weight of concrete per cubic foot as 4050/27 = 150 lb.
Also Read: Modulus of Elasticity of Concrete – Static – Dynamic – Types
Weight of concrete per cubic meter
1 cubic meter is approximately equal to 35.3147 cubic feet. So, if 1 cubic meter concrete weighs around 2400 kg, so weight of 1 cu ft concrete in kg is 2400/35.3147 = 68 kgs. So weight per cubic foot in kg is 68 kgs. In pounds it will be 68 x 2.214 = 150 pounds.
- So, weight of concrete per cubic foot = 150 lbs
- Weight of concrete per cft = 68 kgs
Weight of reinforced concrete per cubic foot
The weight of reinforced concrete in imperial or metric system is about 71 kgs or 156 pounds. That’s because the steel do have a weight added in the concrete. So, a reinforced concrete block of 1 foot height, 1 foot width, and 1 foot length will be 156 pounds (unlike unreinforced concrete that is 150 pounds).
Also Read: Cement Concrete Calculator – Online calculate cement sand and aggregate
How much does 1 foot by 1 foot of concrete weigh
Now if you have got a slab of concrete and want to know the average weight of the slab per square foot, you’ve got to measure the depth of the slab. A slab weight of 1 foot in length and 1 foot in width will weigh 50 pounds with 4 inches thickness, 37.5 pounds at 3 inches thickness, 62.5 pounds at 5 inches thickness and 75 pounds at 6 inches thickness. So, a solid slab weighs approximately 50 pounds per square foot but in broken condition, its weight will be 25 pounds.
Here’s how we can solve the above examples:
Dimensions of slab = 1 foot x 1 foot x (4 inches / 12) = 1 foot x 1 foot x 0.333 (length x width x thickness)
So, the volume of slab will be = 12 x 12 x 4 = 576 cubic inch or 0.333 cubic foot.
Now, as weight of concrete per cubic foot is 150 pounds, so we can solve above as
Weight of slab (1 feet x 1 feet x 4 inches) => 0.333 x 150 = 50 pounds.
So, if you’re looking to know, how much does a 4 inch slab of concrete weight per square foot? It is 50 pounds per square foot.
| Depth of thickness of slab in inches | Weight of concrete per cubic foot (pounds) |
|---|---|
| 3” | 37.5 lbs |
| 4” | 50 lbs |
| 5” | 62.5 lbs |
| 6” | 75 lbs |
| 7” | 87.5 lbs |
| 8” | 100 lbs |
Is concrete heavier when wet or dry?
Now obviously when concrete has water, it will be heavier than if it is dry. However, the water we add in concrete normally goes all with the cement in a chemical reaction that is hydration reaction. So, we can conclude that there will be very less difference between the weight of concrete in dry condition vs weight of concrete in wet condition.
Is concrete heavier than steel?
If we look at the density of concrete, it comes out as 1840 kg/m3 to 2500 kg/m3 whereas the density of steel is 7750 kg/m3 to 8050 kg/m3. So, it is obvious that the steel is heavier than concrete.
However, if we talk in terms of designing buildings – architects or designers have to decide if they want to make a concrete building or a steel building. In that case, steel buildings are lighter than concrete buildings. Approximately steel buildings are 60% lighter than concrete buildings. That’s because steel buildings has thinner section beams or columns and same goes along the need of lighter foundations, unlike concrete buildings.
Calculator
Here’s a very easy to you calculator that will help you in finding the weight of concrete per cubic foot, per cubic inch, per cubic yard, and per cubic meter. Just choose the unit and enter the volume of concrete to get the corresponding weight.
The bottom line
So, you see the weight of concrete per cubic foot is 150 pounds and 68 kgs. A typical mix design of 3000 psi concrete has a cement weight of 20 pounds, sand weight of 57 pounds, and aggregate weight of 59 pounds. Whereas for a typical water-cement ratio, the weight of water is ~14 pounds. However, the weight of concrete in general depends on reinforcement, thickness of slab, concrete grade, type of concrete ingredients, and so on.
