Concrete Grade: Types and Classification Table

Concrete is one of the vital building materials. Therefore, ensuring high-quality concrete is crucial to guarantee robust and durable building structures. Essentially, concrete grade standards are regulated through the Indonesian National Standard (SNI) to ensure its quality.

Concrete grade is the primary factor that indicates the durability, strength, and ability of concrete to support building structures. One of the determinants of concrete grade is the materials used. There are several classifications that distinguish different types of concrete grades.

This article will thoroughly discuss the concrete grade table, types, and other factors affecting concrete grade. Read on for more details.

What Is Concrete Grade?

Concrete grade is an indicator that shows the quality and strength of concrete, usually determined through a series of laboratory tests. These indicators determine how well the concrete can withstand loads and pressures without damage.

Knowing concrete grade is essential in construction projects to ensure safe, stable, and durable building structures. Therefore, planning and testing must also be carried out carefully and meticulously.

Concrete Grade Standards

Several official regulations govern concrete grade standards to ensure its safety and robustness. In Indonesia, the SNI concrete grade table is the commonly used regulation to control concrete grade. Here are some other regulations:

1. Indonesian National Standard (SNI)

The Indonesian National Standard (SNI) regulates various aspects of concrete production and testing. The SNI concrete grade table, compiled by the National Standardization Agency (BSN), provides guidelines on composition, testing procedures, and the quality of concrete used in construction in Indonesia.

2. American Society for Testing and Materials (ASTM)

ASTM provides a series of international standards for testing and building materials, including concrete. These standards regulate methods for testing compressive strength, abrasion, and water absorption of concrete to ensure it meets specific strength and durability requirements.

3. British Standards (BS)

British Standards (BS) are applicable in the UK and some other countries. BS provides specifications for the composition, testing, and use of concrete. These standards are often used as international references in determining concrete grade.

SNI Concrete Grade Table

Here are the concrete grade standards established by SNI:

Concrete Grade	Cement (kg)	Sand (kg)	Gravel (kg)	Water (liters)	w/c Ratio
K 100	247	869	999	215	0.87
K 125	276	828	1012	215	0.78
K 150	299	799	1017	215	0.72
K 175	326	760	1029	215	0.66
K 200	352	731	1031	215	0.61
K 225	371	698	1047	215	0.58
K 250	384	692	1039	215	0.56
K 275	406	684	1026	215	0.53
K 300	413	681	1021	215	0.52
K 325	439	670	1006	215	0.49
K 350	448	667	1000	215	0.48

Factors Affecting Concrete Grade

Several factors can influence the quality of concrete, especially during its production process. Here are the explanations:

1. Mix Proportion

The mix proportion of concrete, i.e., the ratio between cement, water, fine aggregate (sand), and coarse aggregate (gravel), significantly affects concrete grade. The correct composition will produce concrete with optimal strength and durability.

2. Raw Materials

The quality of raw materials such as cement, water, fine aggregate, and coarse aggregate also determines concrete grade. Clean and high-quality raw materials will result in durable and high-quality concrete.

3. Mixing Process

A good mixing process ensures that all materials are evenly mixed, resulting in concrete with consistent strength throughout. Conversely, poor mixing can cause non-homogeneous concrete and reduce its strength.

4. Quality Control

Strict quality control during the concrete production process ensures that each production stage follows established standards. This includes monitoring raw materials, the mixing process, and concrete casting and compaction.

5. Use of Additives

Additives are additional materials mixed into concrete to alter its properties. Additives can enhance strength and weather resistance, reduce curing time, and provide various other advantages as needed in construction.

6. Curing Time

Curing time is crucial to achieving maximum concrete strength. The curing process must be done correctly to maintain the concrete's moisture, ensuring that the chemical reaction between cement and water proceeds perfectly.

Types of Concrete Grade

Referring to the SNI concrete grade table above, concrete is divided into several types classified based on its quality group. Here is a list of concrete qualities along with their uses:

1. Class I Concrete

Class I concrete includes K-100, K-125, K-150, K-175, and K-200. This group is usually used for non-structural casting or in constructions that do not require concrete reinforcement.

2. Class II Concrete

The next classification includes K-225, K-250, and K-275 in Class II concrete. This quality concrete is typically used for structural work, such as road casting, columns, floors, foundations, sloofs, and others.

3. Class III Concrete

Class III is special classification concrete usually used for large-scale construction. This classification includes K-325, K-350, K-375, K-450, and K-500. Examples of constructions using this class include bridge floors and beams, docks, flyovers, runways, underground tunnels, and others.

Concrete Grade Testing Methods

Concrete grade identification is done through several testing methods. Here are some of them:

1. Compressive Strength Test

The compressive strength test determines how much pressure concrete can withstand. This method uses a compression machine that applies pressure to a 28-day-old concrete sample until it breaks. The calculation of this test is based on the maximum load the sample receives.

2. Water Absorption Test

The water absorption test measures concrete's ability to absorb water. This method involves soaking the concrete in water for 24 hours and weighing it before and after soaking. Concrete that absorbs too much water is more prone to damage from freezing and thawing and corrosion of reinforcement.

3. Absorption Test

Similar to the water absorption test, the absorption test focuses on how much water the concrete absorbs under certain conditions. The results provide indications about the concrete's porosity and durability.

4. Abrasion Test

The abrasion test determines concrete's resistance to abrasion or friction. Concrete will be rubbed with abrasive materials to see how much it wears or erodes.

5. Temperature Effect Test

The temperature effect test assesses how concrete reacts to extreme temperature changes. This test works under hot and cold conditions to ensure that the concrete’s structure remains stable and does not crack or damage.

That is a comprehensive discussion about concrete grades and other important aspects. By understanding concrete grade, related standards, and the factors that influence it, construction can be better planned and executed.

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Semen Merah Putih products adhere to the Indonesian SNI quality standards, ensuring that your construction projects are stronger, sturdier, and more resilient. With this level of assurance, you can confidently choose Semen Merah Putih for your construction needs.

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