Concrete is an artificially made stone building material. You can make it yourself or buy ready-made reinforced concrete products from a factory, which reduces construction time.
Concrete can be granite, gravel and dolomite (limestone). Consists of aggregate, water, binders and additives. This is a solution of cement, sand, filler and water, sometimes a plasticizer is also added. Cement binds all components of the concrete mortar. It is best to use coarse-grained river sand; sometimes it is replaced with slag. Before mixing, the sand must be sifted to get rid of excess debris. Crushed stone is often used, because it is the best filler; sometimes it is replaced with gravel or expanded clay.
There is also such a thing as crushed stone fraction, it is determined depending on the particle size. The smaller the stone size, the lower the fraction number. For foundations, they usually use from 20 to 40 - this is the average. A plasticizer is used to impart frost resistance and water resistance to the finished solution. Reinforcing fibers from polypropylene and polyvinyl chloride are rarely added. Concrete is mixed in a ratio of 1:3:6: cement + sand (crushed stone) + water.
Types of concrete
The following types of solution are distinguished:
- By appointment. These include ordinary and special solutions. The former are used for the construction of industrial and civil buildings, while special ones are used for the construction of hydraulic, road and other structures.
- By binder. These include cement, gypsum, silicate solutions, etc.
- By placeholders. There are concrete with dense, porous and special additives.
- According to hardening conditions. They are divided into hardening in a natural environment, under conditions of wet and warm processing at normal atmospheric pressure, and during processing with heat and moisture at atmospheric pressure above normal (autoclave hardening).
Weight of dry and wet concrete
Humidity indicators affect the specific gravity of any materials: sand, gravel, cement. The presence of water in the concrete solution also increases its mass, but when making calculations it is important to remember: it evaporates during the hardening process of the material. The more liquid there was initially, the more significant the difference in the mass of a cubic meter of wet and liquid concrete will be.
| Brand | Weight of dry concrete, t | Mass of liquid concrete, t |
| M100 | 2,18 | 2,366 |
| M150 | 2,181 | 2,36 |
| M200 | 2,182 | 2,362 |
| M300 | 2,183 | 2,358 |
| M400 | 2,170 | 2,35 |
| M500 | 2,180 | 2,355 |
The table provides approximate data, since it is impossible to calculate the exact specific gravity without knowing the composition and proportions of the components. The specified data is relevant for heavy (classical) concrete, widely used in the construction of buildings and structures. When preparing concrete solutions and calculating the mass of a cubic meter, manufacturers must adhere to the standards prescribed in GOST 25192-82 and SNiP 2.03.01-84. These regulatory documents determine the physical and technical characteristics of building materials, including their density.
Taking into account the given data, we can calculate the average weight of a cubic meter of concrete - 2.4 t/cubic. m. The average density can be used in preliminary construction calculations to calculate the approximate load on the foundation and floors. When using reinforced concrete products, approximately 5–7% should be added to the result. The obtained values will also be useful when transporting concrete mixtures and solutions.
How many cubes of concrete are needed for the foundation?
To calculate the number of cubes of concrete, many people use an online calculator. But you can also do this yourself by using the concrete volume formula to calculate. First you need to consider what kind of foundations there are, and, based on their composition, choose a certain formula.
The foundation can be: strip, pile and slab; there are also many other types of foundation, but it is these three that use concrete for pouring.
Formula for strip foundation. Before making the calculation, you need to find out the width and height of the foundation strip. Then we multiply the width by the height and get the volume of concrete needed for pouring. It looks like this: V=S*L, where V is the volume of concrete, S is the cross-sectional area, L is the length of the foundation strip. To get the S value, you need to multiply the width of the tape by the height.
For example, the following values are given: 50 cm - width of the tape, height - 180 cm, length - 49 m. Solution: V = 49 * 0.5 * 1.8 = 44.1 cubic meters of concrete.
Formula for pile foundation. S=3.14*r, S – surface area of one pillar, r – radius of the pile.
V=H*n, where H is the height of each foundation pillar, and n is the number of pillars. For example, the diameter of the pillar is 20 cm, the length is 2 meters. 0.0628 cubic meters of concrete will be required.
Formula for slab foundation. V=S*H. S is the total area of the entire slab, and H is the thickness of the slab. For example, for a slab 5 m long, 5 m wide and 0.15 m thick, you will need: V=5*5*0.15=3.75 cubic meters of concrete.
Strip foundation
The strip base is a closed reinforced concrete structure, immersed in the ground to a certain depth and passing under the load-bearing walls of the future structure. Today this is the most popular, but also the most difficult type of foundation to calculate.
When calculating it, the following quantities are used:
- Length of the outer side of the foundation (D).
- Width of the outer side of the foundation (W).
- Thickness of external (T) and internal (t) structural elements. As a rule, this parameter is taken 10−30 cm greater than the thickness of the wall, which will rest on this part of the foundation.
- The depth of the foundation, depending on the weight of the future building, the type of soil, the level of its freezing, the terrain and climate of the area.
Calculations can be done in different ways. For example, the volume of a structure where the foundation passes under the external walls and under the interior partition located in the middle can be calculated in three ways.
The first method consists of the following steps:
- The area of the figure formed by the outer walls of the foundation is calculated by multiplying the values of L and W.
- The volumes of voids formed by internal structural elements are calculated. To do this, you need to find the product of the parameters d and w and double the resulting value.
- Subtract the second number from the first number and multiply the result by the foundation depth.
The second method is used when constructing foundations of complex configurations or in cases where their different elements have unequal depths. The idea of the method is to break a complex figure into simple components, calculate the volume of each of them and find their sum. The foundation is conventionally divided into rectangular elements, which, for convenience, can be designated in different colors in the drawing.
Next, the area of each rectangle is determined as the product of its length and width and multiplied by the depth of the foundation, after which the resulting values are summed.
The essence of the third method is:
- Find the surface area of the outer foundation walls by first determining their total length. In the example given, it will be: 2W + 2D - 4 T. The resulting value is multiplied by the thickness of T.
- The surface area of the internal walls is determined as the product of the values w, etc.
- The obtained values are summed up and multiplied by the depth of the foundation.
In addition to the rectangular foundation discussed above, there are other types of strip structures. If there is an expansion in the lower part of the base, which may have the shape of a rectangle or trapezoid in cross-section, its volume must be separately calculated and added to the volume of the rectangular part.
Sometimes the bottom of a strip foundation is made wider than its upper part, that is, the cross-section of the side has the shape of an isosceles trapezoid with a height equal to the depth of the foundation. In this case, the order of volume calculations changes slightly.
In accordance with the laws of geometry, the area of an isosceles trapezoid is equal to the area of a rectangle with sides equal to the height of the trapezoid and its midline.
Area of the trapezoid: S = Lh, where L is the midline of the trapezoid, calculated as the sum of the lengths of segments AB (top line points) and CD (base line points of the trapezoid), divided by 2, h is the depth of the foundation.
Area of the rectangle: S1 = Lh (product of the lengths of the sides), that is, S1 = S2.
This means that the volume with a side section in the form of a trapezoid ABCD will be equal to the volume of the foundation with a side section in the form of a rectangle A1 B1 C1 D1, where A1 B1 = C1 D1 = L, A1 C1 = B1 D1 = h.
Calculation with a calculator
There is a special program: online concrete volume calculator. You just need to enter the data in the table; there are explanations for each action. You can calculate how many materials are needed for concrete, sand or crushed stone, for example.
A convenient way to calculate the volume of concrete and its binding components. It is also possible to calculate for one batch or even a bucket. Of course, this calculation will be approximate, definitely, you need to try kneading and look at the result.
This applies to manual mixing of all ingredients. With production mixing, all indicators are, of course, more accurate. Using a calculator, you can also save your time; you do not need to derive all the calculations using formulas yourself. In addition, the possibility of errors is minimal when calculating online. Nobody wants to overpay if the error is large, and then look for a place where this concrete can be determined. And when counting down, of course, you don’t want to call a concrete mixer several times and pay extra for the delivery of concrete. Many calculators have hints.
How to calculate the volume of concrete for a floor?
So, to screed the floor, you first need to make the necessary calculations. The formula for calculating the volume of concrete cubes for a floor screed: V=S*H, where S is the surface area of the screed, H is its thickness. For example, the area is 10 square meters. m, and the thickness of the screed is 0.5 m. V=10*0.5=5 cubes of concrete are needed to screed the floor.
In addition to the volume of concrete, you can determine how much cement is needed if you pour the floors yourself. The resulting amount should be multiplied by 490. This is exactly how many kilograms of cement should be in one cube of concrete. You can calculate the amount of sand, for which you need to multiply the resulting amount of cement by 3, and we will get the exact result.
How to calculate the volume of concrete for pouring walls
Attention! Do not forget that the area of windows and doors does not need to be taken into account. You can simply subtract them from the total area of the walls, and then multiply the remaining values by the thickness - and you get the net volume.
Concrete rings
What is concrete goods? These are reinforced concrete products. Precast concrete rings consist of reinforced steel and concrete. The purpose of these rings is to build wells; this is its frame. You can also calculate the volume of concrete in reinforced concrete rings by turning to Internet resources, using various online calculators for calculations. You only need to know the height, diameter and thickness of the ring.
But there is also a formula for calculating it yourself. It looks like this: V=H*S, where H is the height of the ring, S is its area. To determine the area, you need to calculate the parameters of the outer circle; for this, one-half of the number “pi” is multiplied by the diameter and by 2. It looks like this: S= 1/2π*D*2. Then you need, using the same formula, to calculate the inner circle, and then the area of the inner circle is subtracted from the area of the outer circle, and we get the parameters of the ring.
Weight of 1 cube of concrete?
To answer the question of how much 1 cubic meter of concrete weighs, you first need to know the density of the solution. Of course, the higher the density, the greater the weight of concrete.
Usually in construction they take a value of 490 kg. This is the amount of concrete in one cube, but, to be more precise in this matter, it all depends on its type.
Based on weight, solutions are divided into light, heavy, extra light and extra heavy.
- Particularly light ones weigh up to 500 kg. These are cellular concretes. They contain only sand, cement and foaming agent. Used to make slabs and blocks.
- The lungs weigh from 500–1800 kg. The filler is usually expanded clay, but there are also fillers with a porous structure. Used for pouring screeds, block products, fences.
- Heavy from 1800 to 2500 kg. They have such weight due to heavy fillers such as gravel, crushed stone, and coarse sand. This type is used for screeds and load-bearing structures.
- Particularly heavy from 2500 to 3000 kg. Heavy concrete has a slightly different structure, it largely depends on the brand of cement; the differences in weight, although small, are still there. And this type is produced only in factories.
This is how much 1 cubic meter of concrete weighs, depending on its composition and area of application.
Weight of a cubic meter of concrete
| Type of concrete | Weight 1 cu. m, t |
| On crushed stone or gravel | 2,4 |
| On volcanic slag | 8–1,6 |
| On quartz sand | 8–1,2 |
| On expanded clay sand | 5–1,8 |
| On perlite | 6–1,2 |
| On blast furnace slag | 1,2–1,8 |
The specific gravity fluctuates over a wide range. This is due to differences in the characteristics of concrete: the materials have different grades of density and strength, which depends on the ratio of the components in the composition and the mixing method. Mixes prepared by hand are significantly lighter compared to concrete produced by deep compaction. The amount of water added to the mixture also affects the final results.
Concrete quality indicators
There are 5 indicators of concrete quality, they are designated by letters and numbers. The first indicator is the grade of concrete, for example, M100 - M800, where the numbers indicate the strength of the material. The second indicator is the class of concrete for which the manufacturer provides a guarantee, for example, B3.5 - B60. The third indicator is the frost resistance level F (25–1000). The fourth indicator is the water resistance coefficient, designated W (2–20). The fifth indicator is the mobility of concrete. Designation “P” (1–5).
Brand of concrete. Application
M 100 is used before reinforcement.
M 200 (B 15) - this brand is used for pouring the foundation.
M 300 (H 22.5) – in demand for the construction of monolithic structures and strip foundations.
M 350 (B 25) - produced for the production of reinforced concrete products, pools, piles, etc. are made from it.
M 400 (B 30) - erect bridges, build hydraulic structures.
M 450 (B 35) - sets quickly, so it is used only for the construction of subways, dams, dams.
M 500 (B 40) and M 550 (B 45) are high-strength concrete grades. They are intended for special construction and hydraulic structures.
Columnar and combined base
Columnar foundations are free-standing reinforced concrete columns of round or square cross-section. To calculate the volume of concrete for such a base, you need to:
- Determine the number of supports.
- Find the cross-sectional area of each of them. For round pillars, calculations are performed using the formula for the area of a circle: S = πr2, for square pillars - as the product of the dimensions of the sides.
- By multiplying the cross-sectional area by the depth of the foundation, find the volume of concrete required to pour one support.
- Multiply the resulting value by the number of supports.
The same method is used to determine the volume of concrete for a pile foundation, which is used in the construction of light structures on heaving soils or when the load-bearing layer is deep. If the pile foundation is reinforced with a grillage - a parallelepiped-shaped structure, then the volume required for it is additionally calculated, as is done for a strip foundation.
In the case of a combined foundation, the structure contains elements of a columnar and strip foundation. The calculations determine:
- volume of concrete for pouring columnar elements;
- volume of concrete for pouring strip elements;
- the obtained values are summed up.
No matter how you calculate the volume of concrete, do not forget to add to the result a value that is 10% of the obtained value and round up to whole numbers.
How to protect concrete
In construction, waterproofing helps protect concrete. There are concepts of primary and secondary protection. Primary protection includes a set of measures taken for initial rational protection, for example, the choice of the correct shape, material, thickness of the concrete coating layer, etc. This type of protection also includes impregnation of concrete with special waterproofing mixtures, for example, penetrating.
Secondary protection includes measures for additional coating of concrete. For this purpose, various means are used, thin-layer impregnations, highly filled coatings and self-leveling floors. Foundations, for example, are waterproofed first with roofing felt, and then, when it is completely ready, with bitumen mastic.
It is not so difficult to calculate the volume of concrete yourself, having all the parameters at hand and knowing the formula. It’s even easier to do this with the help of special programs. A concrete volume calculator will greatly simplify the task.
Foundation calculations
Scheme of pouring a concrete foundation.
First you need to determine what type of base will be used in construction. There are 3 types: slab, column and strip. For each of them there is its own way of calculating the cubic capacity of the material used. When pouring a concrete plinth, the so-called compaction coefficient must be taken into account. The fact is that when the material dries naturally, its volume decreases slightly, but when the concrete base is artificially compacted using vibrating plates, this error increases. It makes up approximately 1.5-2% of the total volume of concrete mortar.
Vibrating machine for block production. Installation of prefabricated monolithic ceiling. Concrete mixer device. Read more>>
