Photo Source : freepik.com
Concrete is a composite building that is made from a combination of coarse and fine aggregate, water, and cement as binding agents. Concrete has four main properties that consist of workability, homogeneity, durability, and strength. In this article, we will discuss the compressive strength of concrete.
What is Concrete Compressive Strength?
Strength. concrete , or concrete compressive strength, is the ability of concrete to withstand compressive loads when loaded with a certain compressive force produced by a pressing machine.
The strength of concrete is divided into three types, namely:
- Compressive strength is the ability of concrete to withstand pressure.
- Tensile strength is the resistance of concrete to tensile forces.
- Flexural strength is the combination of compressive strength and tensile strength.
Concrete compressive strength is the most important characteristic of concrete quality compared to other properties. This is because concrete is mostly used for structures that withstand heavy loads, such as columns, beams, and foundations.
The compressive strength of concrete itself is determined by the ratio between water and cement (water-cement ratio), in addition to the quality of aggregate aggregate as a filler.
Concrete Strength Affecting Factors
There are several factors that affect the compressive strength of concrete, namely:
1. Cement Quality
Cement is the main component whose function is to act as glue in concrete and provide compressive strength. Selecting the right cement according to its purpose will produce concrete with optimum compressive strength.
2. Concrete Mixing Ratio
Selecting the right mixture ratio of concrete will produce concrete that is good, dense, easy to work, and has good durability and high compressive strength.
This is one of the most important factors in the concrete manufacturing process to achieve the desired quality. Several properties and proportions that have a dominant influence are the water-cement ratio, cement type, mixed water, aggregate, and additional materials.
3. Curing and Maintenance
Another factor that is no less important in producing concrete with high compressive strength is curing and maintenance. When curing is not carried out properly, it may cause cracks in the concrete and can reduce the value of compressive strength by around 30%.
The second factor is the concrete maintenance, which is carried out after the concrete is finished.
How to Test Concrete Strength
Before being marketed or delivered to customers, the concrete will undergo a testing process. This test is usually called a concrete compressive strength test and is always carried out to find out whether the strength of the concrete meets the needs of the planned building structure.
The test itself is usually carried out on concrete test objects in the form of cubes or cylinders as a representative of the concrete mixture.
The test object is pressed until it breaks, and the compressive strength is measured by the maximum load it can withstand.
Concrete testing life times are regulated in PBI 71, SNI 2847-2019, namely 3 days, 7 days, 14 days, 21 days, and 28 days, where for each test there must be at least 2 test objects.