Concrete is simply an irreplaceable material for construction, which is used everywhere. But in order to choose the right type of solution, it is necessary to take into account the main characteristics of the mass, such as workability, cone settlement and mass mobility. And exactly what the mobility of concrete is is what this article will discuss.

Basic terms and definitions

Before defining the main characteristics of the solution, it is necessary to clearly understand what this building material is.

Concrete is a composition consisting of four main components:

1. Cement;
2. Sand;
3. Water;
4. Crushed stone.

Note! If in , then it's just cement.

The main task . Achieving this goal is only possible if the correct proportions of the two main components such as water and cement are observed.

Sand and crushed stone are referred to as fillers of the composition, and are used to impart strength to the mass and reduce possible deformations of the monolithic product after hardening. It is these fillers that make up the structural frame of a monolithic product, which makes it possible to increase the elasticity of the structure and reduce deformation under severe loads.

Mobility

The mobility or elasticity of a solution is an important property that can influence the choice of material for the construction of buildings and structures for various purposes. Mobility is the ability of a mass to fill the shape in which it is placed.

Note! The ability of a mass to fill a shape can manifest itself both under the influence of external forces and under the influence of its own mass.

According to GOST, the mobility of the concrete mixture is divided into 4 categories from p2 to p5, depending on the amount of added liquid. The less liquid, the thicker the solution, the thickest has the index p2, the most liquid, respectively, p5.

Based on plasticity indicators, building materials are divided into 2 groups:

1. Slow or hard mixtures. They contain a small amount of water and are not able to fill the form in which they are placed under the weight of their own weight without the influence of external forces. Such compositions have indicators p2 or p3. Laying of the sedentary mass is carried out using vibrating and compacting equipment, which makes it possible to remove voids from the monolith;

Advice. If construction work using hard concrete is carried out in winter, the solution must first be heated.

1. High fluidity mixtures, liquid or castable. Solutions of this type have indicators equal to n4 or n5. Such masses are used in the process of pouring formwork, densely reinforced products and do-it-yourself columns.

Dilution with water

The low elasticity of the material can significantly increase the time for construction work if the necessary equipment is not available at the construction site. And in order to solve this problem, many resort to the dilution method, making p4-p5 mixtures from p2-p3 mixtures.

If compaction is carried out correctly and the dilution method is eliminated, then you will get a strong, reliable structure, the mechanical processing of which can be carried out by such methods as cutting reinforced concrete with diamond wheels and diamond drilling holes in concrete.

Mobility indicators

In the case where the grade of concrete in terms of mobility has been chosen correctly, but it is ordered from a supplier and you have doubts about the compliance of the delivered product with the declared characteristics, and the price of the mixture is not so low, then you can check it at the construction site.

The mobility of a concrete mixture can be determined directly during unloading in 2 ways:

• Determination by monolith analysis;
• Cone for determining the mobility of a concrete mixture.

Determination of elasticity by monolith analysis

The instructions for such a test stipulate the possibility of determining any indicator of the plasticity of the mixture:

1. Before starting the inspection, you should build several boxes in the shape of a cube with sides measuring 10-15 cm from wooden boards;
2. Before pouring concrete into prepared forms, the wood should be slightly moistened to prevent moisture from being absorbed from the solution;
3. We pour the solution into the boxes, after which the mass must be pierced with a sharp rod of reinforcement, thus compacting the monolith and releasing the air;

Advice. Additional compaction can be achieved by tapping the walls of the drawers with a hammer.

1. The cubes must dry for 28-30 days at a temperature of at least 20 0 C and a humidity of at least 90%;
2. After the created samples have dried, they should be sent to the laboratory, where the mixture will be checked for compliance with the declared indicators.

The obvious disadvantage of this method is its duration, therefore the method of determining plasticity using a cone is more often used.

Determination of elasticity by cone

The photo shows a diagram of a cone

To use this method, you will need a cone to test the mobility of concrete with a height of about 30 cm. This form should not contain more than 6 liters of material.

This check is carried out as follows:

1. The cone is filled with solution;
2. Concrete is pierced to compact and remove voids;
3. The cone is removed and placed next to the solution;
4. We test for elasticity:
   • If the concrete settlement is 5 cm, then you have hard concrete;
   • If the settlement is more than 5 cm, then you have moving concrete.

Finally

When working with concrete, it is necessary to choose the right grade of material in accordance with the elasticity of the mass and the purpose for which it will be used. Well, if you doubt that, for example, the mobility of P3 concrete is easy to check using the described methods.

The video in this article will tell you even more about how important it is to correctly select concrete in accordance with the elasticity parameters of the mass.

Calories, kcal:

Proteins, g:

Carbohydrates, g:

Corn oil is a fatty vegetable oil obtained from corn seeds. Corn oil has a pleasant smell and taste. Color - from light yellow to reddish brown.

Calorie content of corn oil

The calorie content of corn oil is 899 kcal per 100 grams of product.

Composition and beneficial properties of corn oil

The main advantage of this edible type of oil compared to other vegetable oils is a large amount of (), which is the strongest antioxidant that protects the body from premature aging, as well as corn oil, thanks to, promotes the proper functioning of the gonads, will be useful for women during pregnancy , protects cells from possible mutations (calorizator). Corn oil strengthens the body's defenses, fights fatigue and muscle weakness, thanks to the presence of this type of vegetable oil helps prevent atherosclerosis and reduces the likelihood of blood clots.

Thanks to its balanced composition, corn oil is easily absorbed by the body. It is an easily digestible dietary product.

Use of corn oil in cooking

Corn oil is widely used in cooking. Sauces and mayonnaise are made from it, used in baking culinary products, and used in making food for children.

Types and brands of corn oil

Corn oil is divided into types and brands:

• unrefined,
• refined, non-deodorized,
• refined deodorized grade D (for the production of baby and dietary food products),
• refined deodorized grade P (for supply to retail chains and catering establishments).

To obtain oil, the germ of corn kernels is pressed or extracted. Refined corn oil is golden yellow in color; it is used in the manufacture of confectionery products.

Oil from corn kernels cannot be stored for a long time, as it acquires an unpleasant odor. Therefore, it reaches store shelves refined. During the deodorization process, specific odor substances are removed from corn oil.

For example, the plate has the following designation: P-A, 1, M, Sh, E1, 3500x1750x16, GOST 10632-89

Let's break it down by position:

P-A - means the brand of chipboard.

The standards existing in Russia distinguish two grades of chipboard: P-A and P-B. These brands differ in their physical and mechanical characteristics. Grade P-A is of higher quality and has better bending and tensile strength and lower percentages of swelling, warping and surface roughness than grade P-B.

1 - chipboard grade.

There are slabs of 1st grade, 2nd grade, as well as non-grade slabs, which are usually used for construction purposes. Let us describe the main differences between grades 1 and 2.

On a first grade slab:

Protrusions or depressions, resin or paraffin stains are not allowed; Chips of edges and chipping of corners are not allowed (with the exception of single chips, chipping up to 3 mm and extending along the edge up to 15 mm).

On a second grade slab:

chipping of the edges is allowed within the limits of deviations along the length (width) of the slab; there may be grinding defects on the surface of the slab (no more than 10% of the area); On the surface of the slab, inclusions of bark and large fractions of chips may be present to a greater extent compared to the first grade.

M - type of outer layer of chipboard.

Based on the type of outer layer, a distinction is made between slabs with a fine-textured surface (M), a regular surface, and slabs with outer layers of coarse chips. The latter are used only for construction purposes and for cladding with natural veneer.

Ш - chipboard surface treatment.

The slabs can be polished (Ш) or unpolished.

E1 - formaldehyde emission class in chipboard

The emission class shows the permissible content of free formaldehyde in 100 grams of a completely dry board according to GOST 10632-89. There are two emission classes: E1 (up to 10 mg), E2 (10-30 mg). Manufacturing boards with a high content of formaldehyde is unacceptable.

3500x1750x16 - chipboard dimensions in mm.

GOST 10632-89 - GOST number for chipboard

In addition, the slabs come in regular and increased (letter “B” in the marking) water resistance. In the vast majority of cases, slabs with ordinary water resistance are used. It is advisable to use slabs of increased water resistance for the manufacture of countertops for kitchens, furniture for bathrooms, as well as for special construction purposes. When making waterproof chipboard, before pressing, a special paraffin emulsion or molten paraffin is introduced into the chip mass. An indicator of water resistance is swelling in thickness (over 24 hours, upper limit):

• . regular chipboard, grade P-A - 22%,
• . regular chipboard, grade P-B - 33%,
• . waterproof chipboard - no more than 15%.

In the process of building a house or structure, as well as in the case of roof repairs, an important step is the roofing material. At the moment there are a huge number of them, so the optimal choice is quite problematic. First of all, such material must meet operating conditions, design and loads.

Description of material

Glassine, which serves as a vapor barrier and roofing material, is in great demand. The main material is cardboard (intended for roofing), which is subsequently impregnated with bitumen. The cardboard itself includes about 20-40 layers of flax fibers, cotton, wood or straw, rag masses and other components.

The nonwoven materials that make up cardboard are necessary for its good absorption. Giving glassine the best technical characteristics is achieved if the cardboard is pressed under a pressure of about 300 g/m2. The material itself has become a modern and improved continuation of roofing felt.

Glassine in construction

Types and brands of glassine

Glassine can be either liquid or rolled material. In the first case, glassine is a polymer water-displacing composition designed to protect a wooden surface from rotting. It is used in the construction of bathhouses, log houses and wooden houses, as well as in protecting the concrete base of the foundation from the negative effects of moisture.

The second type is rolled glassine. Its production is carried out in accordance with GOST and is a cardboard impregnated with bitumen.

Based on the thickness of the cardboard and the type of bitumen, the following brands of glassine are distinguished:

• Brand P250. This glassine has the smallest thickness and at the same time is characterized by high strength and elasticity. When the material is stretched, the breaking force is from 15 kgf. With a pressure of 0.001 MPa, glassine of this brand will provide protection against water for 10 hours.
• Brand P300. The material is quite durable and elastic. The breaking force in case of stretching is 22 kgf. For about 20 hours, glassine of this brand will protect the surface from moisture.
• Brand P350. The breaking force is more than 27 kgf, and water absorption is up to 20% of the mass of the material. About 20 hours there will be no sign of water on the surface of the material at a pressure of 0.001 MPa.

It is worth noting that the higher the grade of glassine, the better and more durable it is.

In the photo - liquid and rolled roofing glassine

Liquid glassine Roofing glassine in rolls

Technical characteristics according to GOST

GOST 2697-83 standards apply to glassine, which is a lining material. This material is used as the initial layer of the roofing system.

Glassine brand P350 is a type of roll measuring 100, 125 or 150 cm +/- 0.5 cm. The total area will be 20 or 40 m2 and weighing 15 kg and 30 kg, respectively. A slight deviation in weight is not a sign of defect.

Technical requirements and properties:

1. The ratio of the mass of bitumen and cardboard is from 1.25 to 1 part of cardboard.
2. Breaking load during stretching from 27 kgf.
3. The degree of water absorption (vapor permeability) is up to 20%.
4. With a pressure of 0.001 MPa after 10 minutes there should be no sign of water ingress on the reverse side.
5. Uniform impregnation over the entire surface and thickness of the canvas. When the glassine is cut, it should be black; a brown tint is possible.
6. The thickness of the matte glassine surface without irregularities is more than 1 mm.
7. No cracks, holes or other damage. A maximum of two tears with a length of 1 cm to 3 cm are allowed along the edges.
8. The length of the fabric in a roll is at least 3 m.
9. Evenly cut ends of the fabric.

Glassine is a fairly safe material. This is due to the fact that no harmful substances are used in its production process, and the production itself does not harm the environment. But at the same time, as the temperature in the environment increases, a chemical smell will emanate from the glassine.

Glassine is a new roofing material produced in roll form. It serves as an improved continuation of roofing felt, as it is cardboard impregnated with bitumen. - this is the retention of moisture and steam from getting into thermal insulation materials.

Glassine or isospan

Izospan is a vapor and moisture insulating material that protects a building from the negative effects of moisture both outside and inside a house or building. To make the right choice in favor of glassine or isospan, you need to study their advantages and disadvantages.

Advantages of glassine:

• High mechanical strength;
• Low price;
• Availability;
• High resistance to water.

Advantages of isospan:

• High strength;
• Environmental Safety;
• Possibility of adding fire protection components;
• Moisture resistant.

This is what isospan looks like

Disadvantages of glassine:

1. Strong smell. It appears when the temperature in the environment increases. It takes too long to weather;
2. Short service life (5-7 years);

Disadvantages of isospan:

1. Low strength;
2. In a horizontal position it allows water to pass through.

If we compare these two materials, then it is better to choose isospan for vapor barrier of a living space, and glassine would be the best option for a garage, attic and other non-residential premises.

Table 1. Comparative characteristics on a 5-point scale

Glassine or roofing felt

Ruberoid is used as a roofing and waterproofing material. It is made by impregnating roofing cardboard with bitumen, like glassine, but with an additional coating of two sides with refractory bitumen and sprinkling with talc or asbestos.

Both roofing felt and glassine are roll insulating materials. Glassine, due to the lack of additional coating, has several times worse resistance to biological effects. During the combustion process, the roofing material will begin to melt, and the glassine will begin to burn.

Glassine is often used before laying roofing felt as a heat and vapor barrier. But it is not suitable for waterproofing the outside. Ruberoid, in turn, is able to protect the roof and walls from moisture and negative environmental influences.

Table 2. Comparative characteristics on a 5-point scale

The process of making glassine

Work on the production of glassine includes a number of stages:

• Unwinding and gluing of roofing cardboard;
• Its watering and impregnation with bitumen in a special bath;
• Additional impregnation with the same composition in the chamber;
• Cooling of finished products;
• Winding into rolls.

In order to produce glassine, universal use roofing felt units are used, which are designed for most roll materials. Finished products must have a certificate of conformity.

Corn (maize) oil is not the most popular among vegetable oils, and it cannot be said that it is much healthier than others, for example, sunflower or soybean. It cannot boast of history either. Many vegetable oils were known and widely used in ancient times, and edible corn oil was obtained only at the end of the 19th century in the USA. Nevertheless, this oil also has its advantages.

A rich set of useful substances was found in corn oil: beta-carotene, ascorbic acid, vitamin K, B1, B2, B3, and the content of vitamin E in it is especially high (almost 2 times higher than in). It also contains a complex of polyunsaturated fatty acids called vitamin F, lecithin and other beneficial substances.

Corn oil helps normalize fat metabolism.

Nutritionists advise using this vegetable oil for people suffering from diseases of the cardiovascular system and atherosclerosis. The complex of polyunsaturated fatty acids and lecithin contained in the oil help normalize fat metabolism in the body, resulting in healthy cholesterol levels in the blood. It is especially important that the level of so-called bad cholesterol decreases and the risk of the formation of atherosclerotic plaques and blood clots in blood vessels is reduced.

By normalizing fat metabolism, corn oil helps to lose excess weight, so it is often a component of diets. Like most vegetable oils, it has a laxative effect due to its mild stimulation of intestinal motility. In addition, digestive processes are activated due to the choleretic effect of the oil, since it increases.

Corn oil is beneficial to one degree or another for almost all body systems. When consumed regularly, the risk of cancer and diseases of the nervous system is reduced, the aging process of the body is slowed down, and the immune status is improved. Due to the high content of vitamin E, this product can improve the condition of the skin and hair, which is why it is recommended to add it to the diet of people with dry and flaky skin.

Corn oil is very useful for children, it is considered the safest (allergies to it are extremely rare), is easily absorbed by the body and contains a whole range of substances that promote normal growth and development.

Harm of corn oil

Healthy people should not overuse corn oil because of its high calorie content and large amount of vitamin E in its composition. In order for the body to receive a portion of useful substances, it is enough to consume 1-2 tablespoons of this oil per day.

Production and use of corn oil

Corn oil is produced from the germ of corn seeds, which are a by-product of the processing of this raw material. The oil is obtained by pressing (cold or hot raw materials) or extraction. Refined and deodorized corn oil is consumed as food. Depending on the processing method, there are several brands of this product (we note those that can be found on store shelves):

grade D – refined and deodorized corn oil intended for baby and dietary nutrition;

brand P is also refined and deodorized oil, supplied to retail outlets and catering establishments.

Other brands of oil are used in the production of margarine and for technical purposes.

Refined corn oil should be transparent, light yellow in color, practically tasteless and odorless. Many people believe that unrefined vegetable oils are much healthier than refined ones, so they are in no hurry to purchase the latter. However, the purification process is necessary for corn oil that will be used for food purposes. This is due to the fact that when preparing raw materials for pressing, various chemicals are used, which are then completely removed from the finished product. In addition, when growing corn on an industrial scale, various fertilizers are often used, as a result of which harmful substances can enter the oil, which are also removed from it during refining.