In order to make project spending more efficient, you need to know how to calculate the exact cast concrete material requirement per m3. The reason is that, with an accurate calculation, the estimated cost of the cast can be planned as early as possible so that there is no overrun of funds.
Keep in mind, the process of calculating concrete castings should not be done carelessly. It is because the composition of the mixture can affect the strength and sturdiness of the building structure. If you don’t know how to calculate the material requirements of cast concrete per m3, take a look at the following explanation!
How to Calculate the Material Requirement of Concrete Casting per M3
Before knowing the calculation of concrete castings, first, you should understand what concrete casting is. Concrete casting is a mixture of several materials used in several building structures. The mixture is generally calculated in units of m3.
One of the most frequently used applications of cast concrete is the concrete slab. A concrete slab is a construction structure that functions as a floor or roof panel of a house and is usually used in multi-storey buildings.
In order to make the project run more smoothly, you need to calculate the need for cast concrete for the building slab. For that, there are a few simple steps that can be followed. Here’s the full explanation!
1. Determine the Composition of the Concrete Mix
To have a good-quality concrete that suits the needs of the building structure, you need to determine the concrete mix ratio. Keep in mind, the correct concrete mix formula has been regulated by the Indonesian National Standards (SNI).
The guidelines can be found in Indonesian National Standard (SNI) 03-2834-200, which explains the procedure for Making a Normal Concrete Mix Plan. In this standard, there are various types of concrete quality according to its application.
As for home construction, the quality of concrete that is usually used for building slabs is K-225. The ratio of concrete material for this application is 1:2:3. This means that to produce concrete of K-225 grade, these volume ratios must be maintained.
- 1 part cement.
- 2 parts sand.
- 3 parts gravel.
Based on this ratio, you can find out the requirements of each material to produce 1 m3 of concrete cast with K-225 quality. The weight composition that can be used as a reference is as follows.
- Cement: 371 kg.
- Sand: 698 kg (0.5 m3).
- Gravel: 1047 kg (0.8 m3).
- Water: 215 liters (0.215 m3).
Although there are technical references, in practice, workers can still calculate manually according to conditions in the field. However, at the very least, the calculation result still refers to the predetermined standards.
2. Calculate the Volume of Concrete Slab
As a case study, the concrete slab built on the second floor of a residence has dimensions of 3x5 meters with a thickness of 10 cm (0.1 m). To calculate the volume of the concrete slab, you can use the following formula.
- Volume of concrete slab = Length of concrete slab x Width of concrete slab x Thickness of concrete slab.
- Volume of concrete slab = 5m x 3m x 0.1 m = 1.5 m3
So, based on this calculation, the volume of concrete slab that needs to be poured is 1.5 m3.
3. Calculate Concrete Material Requirements
After knowing the volume of the concrete deck, the next step is to calculate the concrete cast material requirements per m3 based on this volume. The following is how to calculate the needs of each material (with the results of the calculation of the concrete deck volume of 1.5 m3):
a. Cement
Cement requirement = Cement requirement per 1 m3 of cast concrete x Volume of concrete slab.
Cement requirement = 371 kg/m3 x 1.5 m3 = 556.5 kg.
Generally, cement available in the market is sold at 50 kg per bag. To find out how many bags are needed, to the following calculation:
Quantity of cement required = Cement requirement : weight of cement/bag.
Quantity of cement required = 555.5 kg : 50 kg = 11.3 bags = 12 bags.
b. Sand
Sand requirement = Sand requirement per 1 m3 of cast concrete x Volume of concrete slab.
Sand requirement = 0.5 m3/m3 x 1.5 m3 = 0.45 m3
c. Gravel
Gravel requirement = Gravel requirement per 1 m3 of cast concrete x Volume of concrete slab.
Gravel requirement = 0.8 m3/m3 x 1.5 m3 = 1.2 m3
d. Water
Water requirement = Water requirement per 1 m3 of cast concrete x Volume of concrete slab.
Water requirement = 0.215 m3/m3 x 1.5 m3 = 0.3225 m3 or 322.5 liters or water
Based on the above calculations, the following are the final concrete cast material requirements.
- Cement: 556.5 kg or 12 bags of cement.
- Sand: 0.75 m3.
- Gravel: 1,2 m3.
- Water: 322.5 liters.
After knowing the material requirements of concrete castings per m3 above, you can calculate the estimated cost required. To do this, research the price of materials available on the market, then multiply it by the amount of each material needed.
Read also: How Much Sand Requirements for Cast Per M3? Here’s the Answer!
Tips for Making Strong Concrete Castings
Making your own concrete castings is a bit more challenging than using ready-mixed concrete. However, it is still very much possible. In order for the concrete cast to support a sturdy building structure, follow these tips:
1. Determine the Building Concept
Keep in mind, the concept of the building affects the material requirements of the concrete cast required. Not only that, some concepts may require additional structural elements that cause an increase in the volume of concrete slabs.
2. Understand the Technique of Making Concrete
With the right manufacturing techniques, concrete castings can provide optimal strength so that they can meet the set standards. Therefore, it is important to understand the appropriate casting procedure, be it manual or with the help of a concrete mixer.
3. Use Quality Materials
Although it may cost more, quality cast materials will produce high compressive strength of concrete compared to ordinary ones. Thus, the building will be more durable and able to protect its occupants well.
One of the materials that you can use to support a strong building structure is Semen Merah Putih Watershield. With triple protection capabilities, this cement will protect your building from 3 sources of seepage: outside, inside, and from the ground.
4. Clean Up Immediately
If the concrete cast is splattered during the application process, clean up the splatter as soon as possible. Do the same if the concrete leaks. This is important to ensure the casting results stay neat and easy to maintain.
5. Check the Condition of the Concrete Castings
After the casting process, don't forget to keep an eye on its condition regularly. The goal is to repair the concrete cast as early as possible when there is a leak or there is an inappropriate formwork position.
6. Reminding the Field Workers
Even though you have informed the workers on site of the casting standards, sometimes mistakes can still occur, such as a concrete cast that is too thin or an inappropriate aggregate composition. Thus, don't forget to keep an eye on the conditions in the field.
7. Consider the Need for Beams
If you are working on a construction project with a large building structure, make sure to use beams in the concrete cast for the safety of the building. Therefore, do not forget to calculate the volume of beams in the material planning process.
Read also: Characteristics and Ideal Thickness of Second-Floor Slabs
This is how to calculate the need for concrete castings per m3, and some important tips so that this mixture can support the strength of the building. By calculating it correctly, you can also find out the estimated construction costs easily.
However, it turns out that, in addition to making concrete castings manually, you can also utilize ready-mixed concrete for construction projects. Not only is it more practical, but this solution can also save your project time significantly.
Through one of its subsidiaries, Beton Merah Putih, Semen Merah Putih presents a variety of innovative ready-mixed concrete products with high strength and diverse applications, such as Ready-Mixed Concrete, Precast Concrete, and Aggregates.
If you need a superior quality concrete cast, take advantage of the Beton Ready Mix from Merah Putih Beton. However, if precast concrete is more necessary, Precast Concrete is here to fulfill your needs.
Still confused about which is the best solution for your construction needs? Contact us and get the best deal!
Read also: Precast Concrete: Definition, Functions, and Types
