Concrete m100: applications. characteristics and
What is concrete of lower strength class used for? What are the composition and proportions of concrete M100? How to properly stack and, if necessary, handle after the set of strength? Let's try to answer these questions.
general information
According to GOST number 7473-94, all ready-made concrete and dry concrete mixes are classified (and, accordingly, marked) according to several parameters.
| Parameter | Description |
| Strength | Максимальное усилие на сжатие, которое способен выдержать без разрушения монолит после набора марочной прочности. Strength измеряется в мегапаскалях (МПа) или, что привычнее, в килограммах на квадратный сантиметр поверхности (кгс/см2). Value прочности в кгс/см2, собственно, и соответствует марке прочности: марка М200 означает способность противостоять давлению в 200 килограмм на сантиметр, М350 - 350 кгс/см2 и так далее. |
| Workability | This parameter describes the ability of concrete to fill the form without external influences. Mixtures are divided into movable, rigid and super-rigid. Mobility is determined by the ratio of aggregates (sand, rubble) and cement. To improve the workability, special plasticizer additives are used. |
| Frost resistance | This is the name of the number of freezing and defrost cycles that a monolith can withstand without complete or partial destruction. The cause of destruction with a large number of freezing cycles is the crystallization of water in the pores; accordingly, the higher the density of concrete, the more it is generally frost-resistant. |
| Water resistant | And this property is associated with the density of the material: the smaller the pores in it - the less likely the water will penetrate. |
Practical consequence: as a rule, water resistance and frost resistance increase along with strength. Dependence, however, is nonlinear: special mineral or synthetic additives are used to impart a mixture of a particular property along with changing the proportions of cement and filler.
Along with the division by strength grade, another concept is used - the class of concrete. Actually, a class is the same maximum compressive force, only expressed in megapascals; class is indicated by a numerical value after the Latin letter B.
Таким образом, тяжелый класс бетона В75 М100- это смесь, которая после набора прочности способна выдержать давление в 7.5 MPa, or 100 kgf / cm2. Слово «тяжелый» указывает на то, что при производстве не использовалось вспенивание или поризующие добавки: если плотность тяжелого М100 примерно равна 2400 кг/м3, то керамзитобетон М100 в два раза легче - от 900 до 1300 кг/м3.
Areas of use
The strength mark we are talking about is considered minimal.
Here are some examples to compare:
- When pouring the foundation for a low-rise building, the M200 brand is usually used.
- Bearing elements (beams, floors) in frame-monolithic housing construction are usually made of concrete M300 and above.
Useful: in addition to the compressive loads, the frame experiences both tensile and bending loads. They are perceived by rebar; the larger the estimated deforming loads, the tighter the reinforcement.
- Maximum strength grade - M1000 (class B80).
Since the material is not resistant to loads, the use of concrete M100 is permissible only where they are insignificant:
- To perform a concrete pad under the foundation. It prevents the outflow of cement milk when pouring the foundation and protects the lower layer of reinforcement from corrosion.
- For concreting road curbs, fences, low pillars, etc.
Description
Specifications
We have already described the key technical characteristics of concrete M100. Repeat
| Parameter | Value |
| Strength | 7.5 MPa, or 100 kgf / cm2 |
| Frost resistance | F50-100 (from 50 to 100 cycles of freezing and thawing) |
| Density | 2370 - 2400 kg / m3 |
| Water resistant | W2 - 4 |
| Workability | P4 - J4 |
Recall: frost resistance and water resistance can be modified additives. Say, it is easy to increase the water resistance of the mixture with your own hands by adding a small amount of sodium liquid glass to it.
Composition
The main components are quite common:
- Portland cement.
- Sand.
- Crushed stone (in our case, it is permissible to use not only crushed granite, but also limestone).
The percentage of cement, sand and gravel - 1: 4.6: 7.0.
Composition бетона М100 на 1м3:
- Water - 0.21 m3.
- Sand - 0.58 m3.
- Crushed stone (commonly used fraction of 10 - 20 mm) - 0.8 m3.
- Portland cement M400 - 5 bags of 50 kg each.
Cost of
The current price of a cubic meter of concrete varies from 3,000 to 4,000 rubles, depending on the region.
Construction works
Fill
Instructions for preparing the surface for a concrete pad and pouring it are not difficult.
- The ground or bottom of the pit is leveled. In most cases - strictly in the horizontal plane; however, when concreting sites in the open air, they often have to be made inclined, both because of the specificity of the relief and for the flow of water.
- Sanding or rubble (usually 15-20 centimeters).
- Подсипка трамбуется. Sand, however, can simply be poured for maximum shrinkage with plenty of water.
- Concrete is laid out in a uniform layer up to 10 centimeters thick.. Splicing and vibrolayer in this case do not apply.
Treatment
In most cases, it comes down to dismantling. Due to the low strength of concrete, this work is easy to perform with both a jackhammer and ordinary crowbars.
In those rare cases when, after pouring a pillow, it is necessary to make technological holes in it, any means can be used:
- A conventional drill with a bit or bit is suitable if there are no special requirements for the quality of the edges of the hole.
- If the edges have to be perfectly smooth, it is better to use a diamond tool. Diamond drilling of holes in concrete does not require the use of a percussion mode of the tool and does not give chipping.
Note: for the same reason, for large openings, cutting reinforced concrete with diamond circles is preferable. Among other advantages, the diamond disc does not require replacement when the armature passes.
Conclusion
We will consider our acquaintance with concrete of a lower class of strength held. As usual, the video in this article will offer the reader additional topic information. Successes!