Portland cement of the M400 brand is one of the most popular building materials. This versatile mix, delivered as a dry powder, is widely used in private and industrial construction. Reacting with water, cement forms a plastic solution, which after a certain time turns into a solid state and retains its strength for hundreds of years.
Portland cement of the M400 brand is able to harden not only in air, but also in water. This unique property of the material has significantly expanded the horizons of its application.
What does the M400 marking mean?
The brand of cement determines the brand of finished concrete when it is manufactured in strict accordance with the technical documentation and compliance with technical processes according to GOST. Grade of Portland cement-a conditional value that is expressed in numbers (in this case – 400) and means the strength of the finished product after aging for 28 days. The number 400 indicates that the compressive strength of this material is at least 400 kg per square centimeter.
The marking of cement also reflects the presence / absence of modifier additives in the mixture, which change the characteristics of the solution (improve anti-corrosion characteristics, increase the moisture resistance of the mixture, increase the speed of solidification, etc.).
According to the approved standards, Portland cement of the M400 brand can be produced in pure form (in this case, the index “D0″ is indicated on the package and in the accompanying documentation), or with special modifying additives (the index — D5-D20 is present on the package). The letter ” D ” indicates the presence of additives in the cement, and the numerical designation indicates their amount (D5-5% of additives, D15-15% , etc.).
The main function of modifying additives and plasticizers is to give the mortar and concrete additional characteristics. This can be increased resistance to the aggressive action of seawater, an increased number of frost resistance cycles, rapid or delayed hardening, and the like. The manufacturer can introduce technological additives into the cement composition, for example, to facilitate the grinding process of Portland cement clinker and gypsum stone, improve the transportation of cement, etc.
According to the rules adopted several years ago, one of two designations is indicated in the marking.:
- CEM I-pure Portland cement, without the use of additives;
- CEM II is a Portland cement with additives in its composition.
In the new standard, there is no concept of brand, but there is a concept of strength class. If by Soviet standards the strength of Portland cement was denoted kg per square centimeter, then under the new rules it is denoted in megapascals (MPa). The M400 brand corresponds to the designation-32.5.
Then the label should have a subclass: H-normalcools or B-fastcools. Example of decoding the PC according to the modern standard of designations:
CEM II 32.5 B-Portland cement with modifying additives, the strength of this type of cement corresponds to the rapidly hardening grade M400.
Technical specifications
Portland cement of the M-400 brand is a complex composition of components of mineral origin that are in an aggregate state. The composition of the mixture is dominated by oxides of calcium, magnesium, aluminum, iron, and silicon oxides. The share of mineral components reaches 98%.
Cement M400 in accordance with the requirements of GOST 31108-2003 must meet the following characteristics::
- Compressive strength (after 28 days) – not less than 30 MPa;
- Start (time) of setting – at least 60 minutes, strength (up to 98%) is achieved after 28 days;
- Density in the loosened state – 1000-1200 kg per cubic meter;
- Uniformity of volume change-no more than 10 mm;
- Frost resistance-operating temperature range -60 – + 300 degrees, 70 cycles of complete freezing / thawing;
- Water resistance of cement that has fully gained strength is high;
- Shelf life for sealed packaging is up to one year.
Scope of application
Portland cement M400 is used with great success for the manufacture of various reinforced concrete structures. Due to its high resistance to low temperatures and high humidity, the material is suitable for the construction of underground facilities. Products based on M400 cement meet all the requirements, are characterized by high strength and stability.
The scope of application of Portland cement in construction is very large: from mixing plaster solutions based on sand to heavy concreting of loaded critical structures. Cement of the 400th grade is indispensable for general construction work, today it is used to solve a wide range of tasks:
- preparation of standard masonry mortar;
- concreting of foundations;
- production of construction and finishing materials (paving slabs, expanded clay blocks, etc.);
- manufacturing of high-density load-bearing elements;
- production of floor slabs;
- construction of bridge crossings and other load-bearing structures;
- production of reinforced concrete products-curbs, precast blocks, monolithic concrete boxes;
- during the construction of structures operating in high humidity conditions;
- for installation of pile foundations, etc.
M400 cement consumption rates
To select the optimal ratio (composition) of concrete, you should determine the water-cement ratio, that is, the proportions of water and cement. Crushed stone and sand should also be used in a certain proportion. Only with strict adherence to the technology can you get concrete of the required strength and characteristics.
For the production of one cubic meter of high-quality concrete of the common M200 brand, 500 kg (10 standard bags) of M400 cement are required.
For the production of a cubic meter of M100 mortar, the consumption of M400 cement will be about 300-325 kg. Consumption of M400 grade cement per screed is 575 kg per cubic meter.