Modern construction relies heavily on concrete because of its unparalleled durability and adaptability. The compressive strength of concrete is one of its most important properties. This characteristic plays a crucial role in the design and construction of buildings, bridges, and other infrastructure because it establishes the maximum load that a concrete structure can support before failing.

For anyone working in the construction industry, it is imperative to comprehend compressive strength. It affects choices about the kind of concrete mix to use, how much reinforcement is required, and how stable and safe the structure will be overall. Through the use of compressive strength, engineers can guarantee that concrete will function as planned in a variety of scenarios.

The units of measurement for compressive strength are usually pounds per square inch (psi) or megapascals (MPa). Concrete samples are put through a controlled pressure test until they break in order to ascertain this strength. The outcomes of these tests assist engineers and builders in determining the quality and fit of the concrete for particular projects.

The methods for measuring compressive strength, the variables that affect it, and its importance in building projects will all be covered in the sections that follow. Knowing the compressive strength of concrete is essential for creating sturdy, safe structures, regardless of experience level in the industry.

- Concrete strength
- Methods for determining strength
- Destructive method
- Non-destructive method
- Classification and application of concrete
- Conclusion
- Video on the topic
- Determination of concrete compression strength
- Determination of the ultimate strength of concrete compression
- 3 1 concrete strength – determination by compression method

## Concrete strength

One important determinant of concrete’s bearing capacity is its strength. The material’s compression limit, or the maximum load limit at which the sample starts to collapse, is calculated experimentally.

The resistance of concrete to loading effects is what we mean when we talk about its calculated resistance to axial compression. This indicator is used in design calculations and is linked to standard parameters.

Designers used material grades up until 2003, when a new classification system was implemented. The class of concrete is represented by the letter "B" and is expressed in MPa, while the grade of concrete for compression is indicated by the letter "M" and indicates the tensile strength expressed in kgf/cm 2.

There is more than just a change in measurement units. The assurance of confirmation of the material’s strength is the primary distinction between the classifications. The grade denotes the mean value, and the concrete’s compressive class ensures that, in 95% of testing scenarios, the required strength is guaranteed and that there is a maximum 5% chance of deviation from the standard indicators.

Concrete strength class | Concrete grade | Average strength of concrete of this class (kgf/cm 2) |

B7.5 | M100 | 98 |

AT 10 | M150 | 131 |

B12.5 | M150 | 164 |

B15 | M200 | 196 |

IN 20 | M250 | 262 |

B22.5 | M300 | 302 |

B25 | M350 | 327 |

B30 | M400 | 393 |

SP 52-101-2003 "Concrete and reinforced concrete structures without prestressing reinforcement" reflects current standards. Optimal characteristics in concrete and reinforced concrete structures can be designed with the aid of modern classification.

There is a chance that the computed properties of the material will be less than the actual ones when using average strength indicators (concrete grade). The concrete structure’s dimensions must be increased to be on the safe side if average indicators are used as the lowest, which results in a discernible increase in cost.

## Methods for determining strength

The axial compression of concrete can be found in two ways. Certified and verified equipment is needed in both situations.

### Destructive method

To carry out tests, you require:

- press;
- caliper;
- laboratory scales;
- 3-5 pre-prepared samples from the test batch – concrete cubes with sides of 100 mm.

The samples need to be completely flat on the edges and free of dirt. One by one, they are put on a press and loaded, with the maximum value at which each sample starts to collapse being recorded in the protocol. The average actual value is calculated based on the findings and contrasted with the standard and design indicator.

Construction sites and factories that produce products made of reinforced concrete are required to use this technique. The most trustworthy laboratory studies use the destructive method; designers and architects consider the values that are obtained.

### Non-destructive method

When using the previous method is not feasible, concrete can be tested for compression using a special device. The following properties of completed structures are examined using the impact pulse method, and the material is tested on site using an electronic meter:

- strength;
- density;
- elastoplastic properties.

GOST 22690-2015, "Concrete. Determination of strength by mechanical methods of non-destructive testing," governs this procedure.

## Classification and application of concrete

Let’s examine how the concrete resistance to compression indicators impact the material’s application range. The list shows the concrete class and the strength grade that is most similar to it:

- B0.35-B2.5 (M5-M35) – preparatory work, structures without a load-bearing load;
- B3.5-B5 (M50-M75) – concrete under monolithic foundations, arrangement of a cushion and installation of curbs in road construction;
- B7.5 (M100) – similar to the previous material, as well as the arrangement of paths and blindings, the manufacture of road plates, filling foundations, erecting low -rise buildings;
- B10-V12.5 (M150)-the manufacture of structural elements (jumper and t.D.), the construction of low -rise buildings (up to 3 floors);
- compressive strength of concrete B15 -B22.5 (M200-M300) – foundations, monolithic stairs, platforms, retaining walls, construction of monolithic buildings up to 10 floors high;
- compressive strength of concrete B25 -B30 (M350-M400) – monolithic foundations, swimming pool bowls, other critical structures, construction of monolithic buildings about 30 floors high, production of reinforced concrete structures for the installation of pile-grillage foundations, beams, columns and other reinforced concrete products, hollow-core slabs floors, airfield slabs for operation with extreme loads.
- B35 (M450) – hydraulic structures (including dams and dams), bridge structures, production of reinforced concrete products and concrete products with special strength requirements, arrangement of bank vaults;
- B40 (M550) – use is similar to the previous material, colloquially referred to as “concrete 500”;
- B45-B60 (M600-M800) – also used for the construction of facilities and the manufacture of reinforced concrete structures with special requirements.

Monolithic structures, reinforced concrete structures, and concrete products are the main applications for concrete with compressive strengths of B30, B25, and B15.

## Conclusion

The concrete compression calculation step of the building design process is required. The following are some of the variables that affect the material’s strength:

- quality, characteristics, set and ratio of components;
- conditions for manufacturing structures;
- compliance with technology, etc..

It’s critical to verify the material’s true strength following the production of reinforced concrete products, reinforced concrete products, or the strengthening of monolithic structures.

Strength Class | Description |

C10/12 | Low-strength concrete used for non-structural elements like pathways. |

C25/30 | General-purpose concrete used in residential buildings and light commercial structures. |

C35/45 | High-strength concrete used in commercial buildings and infrastructure projects. |

C50/60 | Very high-strength concrete used in specialized structures like bridges and high-rise buildings. |

C70/85 | Ultra-high-strength concrete used in critical structures requiring maximum durability. |

Comprehending the compressive strength of concrete is essential to guaranteeing the longevity and security of constructions. This characteristic gauges the amount of pressure that concrete can bear before breaking. It affects many facets of building, from figuring out the proper mix to assessing a building’s ability to support loads.

It’s critical to utilize the right ingredient mixture and adhere to recommended curing procedures in order to obtain the required compressive strength. Important factors include the type of aggregates used, the curing process, and the water to cement ratio. Building professionals can create concrete that satisfies particular strength requirements by paying attention to these details.

To ensure that the concrete satisfies the necessary strength standards, testing must be done on a regular basis. Tests of compressive strength are beneficial.

Compressive strength of concrete is a crucial characteristic that establishes the ability of concrete structures to support loads. It is crucial for guaranteeing the stability and safety of structures and infrastructure since it indicates the amount of pressure that concrete can bear before collapsing. Numerous elements, including the composition of the materials, the method of curing, and the surrounding environment, affect this strength. Compaction strength is a property that builders and engineers can test and understand to create durable and dependable concrete structures.

## Video on the topic

### Determination of concrete compression strength

### Determination of the ultimate strength of concrete compression

### 3 1 concrete strength – determination by compression method

**Which aspect of concrete application are you most interested in?**