The quality and durability of concrete products largely depends on the brand of selected concrete. It must correspond to the conditions of operation of the product. In particular, if the constant contact of the material with water is meant, then it is necessary to use waterproof concrete, for example, the W6 brand, which, in fact, is devoted to this article.
Waterproof concrete
Marking of waterproof concretees
Waterproof of concrete, as it is not difficult to guess - this is its ability not to pass water under certain pressure. As a rule, such material is used in the construction of all sorts of hydraulic structures, including water tanks. However, it should be noted that it happens the most different species And designed for different purposes.
In particular, the hydraulic concrete is primarily divided by waterproof to:
In addition, it is distinguished by the following types:
To properly choose the material, you need to understand it in its notation, which we will look below.
In the photo - Hydraulic constructions
Designation of waterproof
As for waterproof, the material is divided into the following brands - W2, W4, W6, W20. The numbers suggest that with what pressure it does not miss water. Thus, the W6 concrete waterproof is 0.6 MPa.
Compressive strength
Another one an important indicator It is compressive strength. The material parameter is determined at the age of 180. For construction, concrete classes B10, B40. For example, the class B10 corresponds to the brand of concrete M150, B20 - M250 brand, and B30 -M400.
Frost resistance
Hydrobeton is also divided according to the degree of frost resistance. There are five of its brands - F50, F100, F150, F200 and F300. In this case, the figures indicate the number of cycles of freezing and defrosting, after which its strength will decrease by no more than 25 percent.
Tip!
The requirement of frost resistance is imposed only to those hydraulic materials that are subjected to using the simultaneous exposure to water and frost.
Since the price of the solution depends on this indicator, it does not always make sense to acquire it.
Now, having understood with the characteristics of the marking, you can easily determine the characteristics of the concrete W6. What will make it possible to pick up most suitable material For operation in certain conditions.
For example, concrete B20 W6 F150:
Pouring foundation concrete W6
Application
At first glance, it may seem that in the construction of private houses with their own hands and in other domestic purposes there is no need for waterproof concrete, since hydraulic structures are very rare. However, in reality it is not.
For example, the foundation of the house has to constantly contact with moisture. Therefore, it is necessary for its construction at least concrete B25 W6 F150. Moreover, to make a concrete foundation of hermetic, you need not only to use waterproof material for it, but also ensure the waterproofing of the seams.
Bowl of the pool
Also, the characteristics of concrete B25 W6 F100 allow you to use it during the construction:
Foundation Scene
Concrete B20 W6 F200 can be used when executed:
Tip!
Durable concrete brands are seriously treated.
Therefore, for these purposes, a diamond tool is used, for example, a diamond drilling of holes in concrete or cutting of reinforced concrete diamond circles is used.
How to make waterproof concrete
Concrete is a capillary and porous material, as a result of which, with a certain pressure, it becomes permeable for water. It follows that permeability depends on the nature and degree of porosity of the array. The more dense the structure will be, respectively, above water resistance.
Here are the main reasons for which pores occur:
To get a material with a high degree of waterproof, the amount of water needs to minimize. The optimal is the value in / c \u003d 0.4.
Waterproofing additive
Reducing the watercraft ratio, for example, with a / c \u003d 0.5 to the indicator in / c \u003d 0.40, i.e. 20 percent achieved with plasticizers or otherwise - waterproofing additives.
Thus, to obtain, for example, concrete B25 F200 W6V6 is possible and independently, even without vibration. Instructions for the use of these additives can be different, so before use, you should read the instructions from the manufacturer on the package.
Application in the construction of waterproof concrete, such as W6, allows to significantly extend the life of concrete structures. The only one, when choosing a material, it is necessary to pay attention to the other characteristics, such as strength and frost resistance.
From the video in this article you can get additional information on this topic.
Operational and technical characteristics are especially important if we are talking about building materials. Any professional construction sphere will confirm that on the level of product quality used in the process of the construction of architectural and functional structures, it completely depends on how long the operational period of the building and the comfort of the implementation of solutely any activity in the walls of the structure will be. One of the most common building materialsAs practice shows, is concrete. This product has a high level of water resistance. This characteristic even underlies a certain classification of this product is brands of concrete on waterproof.
Resistance to the harmful effects of moisture is hardly the key property of the building material. It is due to a specific structure of a substance that is practically devoid of any void and is quite dense. The seams located between the blocks are carefully filled with a specialized composition with waterproofing characteristics. Speaking precisely about the waterproof concrete, it is worth saying that his structure is very specific, which, of course, gives him a lot of advantages and allocates among the analogues, in a wide variety of proposed in the domestic and world market.
Waterproof - Important property for concrete
The possibility of using this type of products is determined by the structural features of the future building. For example, waterproof building materials should not be used for buildings that do not belong to the monolithic category. The fact is that in the buildings, the construction of which implies mainly assembly works, too many seams. A large number of seams practically eliminates the possibility of achieving waterproof.
Specialists of the relevant sphere offer a very convenient classification. We are talking about separation different types material on stamps on waterproof. Concretes that are resistant to moisture in the appropriate literature are denoted by alphanumeric indices. Such an index necessarily includes the letter W, as well as the numeric range from 2 to 20, excluding odd values. Depending on the pressure that is able to withstand building materials, it is assigned a one or another index number.
The described characteristic is influenced by a wide range of diverse factors, including such as:
The presence of pores in the structure of the product practically does not leave him a chance of fighting moisture. Thus, when the solution is kneading, both manual and mechanical, as well as in the process of solidification of the substance, it is necessary to create all conditions due to which the pores will not arise in the finished product. However, no matter how try, sometimes it is still impossible to create a substance of the appropriate quality. The reason for this is primarily the following:
In this case, careful attention, especially for newcomers, is worthy of shrinkage and the consequences that it causes. Regardless of the brand of concrete on frost resistance and waterproof, its shrinkage is obliged to be the smallest. In order to minimize the risk of problems associated with excessive shrinkage of building materials, it is necessary to produce the following types of work:
One way or another, before proceeding to the implementation of activities, in any way related to the use of waterproof concrete, it is necessary to study the characteristics characteristic of the specific class of goods.
Domestic and foreign manufacturers of goods of this category offer us a wide variety of options. The newcomer in the construction sector, as a rule, it is enough not easy to determine which brand is necessary specifically in his situation. Thus, before proceeding with the direct choice of material, it is worth examining information about existing marking options, as well as on the use of individual classes during the construction of an architectural and functional object.
With respect to waterproof, GOST, specially designed at the state level, makes certain requirements. The accuracy of compliance with these requirements determines the concrete brand for waterproof. The proposed classification allocates concrete brands for waterproof with the index W2 and W4, as well as W6, W8 and even W12. Indexing ends with the W20 number. Experienced professionals advise to avoid the use of products whose mark is lower than W6. Meanwhile, even the best categories exist some limitations. Nevertheless, the labeling helps beginners and even more experienced workers to deal with what magnitude of the pressure will be calculated by a concrete mix.
Two types of factors have the bulk of the impact on the quality of the interaction of the described building material with water. We are talking about such as:
As far as indirect factors did not seem, in reality, as a rule, repel solely from the impact of direct. They are at least convenient to navigate to inexperienced employees. Based on this, you can highlight the three most popular and widely used stamps of building materials:
Waterproof brand Over the index W8 is even more hydrophobic. Thus, it can be argued that a fully reliable product with a W20 waterproof of concrete, the waterproof of concrete will in this case cost a considerable amount of money, but it will also provide the longest operational deadline for the architectural structure of any type.
In order to expand the range of works, the implementation of which allows the operation of this building material, the manufacturers indifferently improve its recipe. Conducted studies and experiments allowed to add to the number of advantages of building materials one more positive propertyWe are talking about frost resistance. For example, products in the W8-W14 range - the basis of the construction of the maximum solid objects, among which there are hydrotechnical structures, reservoirs and even bunkers.
Sometimes it happens that we have to deal with the need to measure yourself if not a brand of waterproof, then at least this characteristic in general terms. Specialists have developed a number of methods, resort to which can be in a similar situation. They are conventionally divided into:
Before proceeding with the consideration of auxiliary techniques, the number of which exceeds their main analogs, it is necessary to consider fundamental ways:
The complex of the methods of the auxiliary category is:
The value of water pressure, which is measured in MPa x 10 -1 is a factor that determines the conditions for the upcoming operation of the building materials. Of course, developing stamps on waterproof, try to give your product best properties For all existing parameters.
Manufacturers do not hide how many varied additives are used. Waterproofing abilities of the substance are directly related to what the nature of its additional components. It can be made surprisingly durable and maximum moisture resistant. Nevertheless, it is important to remember that the use of such products is relevant exclusively in the horizontal plane. Otherwise, the solution is simply stitching on the construction site. Meanwhile, if you can boast a large number of resources such as time and strength, you can pull the restraining film, which fixes the mixture in a vertical position.
The domestic market is replete with additives for every taste. Speaking of taste, it is worth saying that the cost is meant here. The most sought-after goods in this market segment are called:
In order to save money, many prefer to buy calcium nitrate. It is indeed the least expensive option, but at the same time its resistance to the harmful effects of moisture is practically not inferior to the analogues. In addition, you will not actually be difficult to add this ingredient to a solution, as it is remarkably soluble in water and, especially important, is completely safe for human health.
Waterproof concrete: brands, characteristics and specificity of application Updated: January 1, 2017 by the author: Artyom
GOST 12730.5-84
Group w19.
Interstate standard
Concretes
Methods for determining waterproof
Concretes. METHODS FOR DETERMINATION OF WATERTIGHTNESS
ISS 91.100.30
Date of introduction 1985-07-01
Information details
1. Developed by the research, design and design and technological institution of concrete and reinforced concrete (NIIZB) State Building of the USSR, Donetsk PromstroyNIK project of the USSR State Building, Ministry of Transport Construction of the USSR
Submitted by the research, design and design and technological institution of concrete and reinforced concrete (NIIZB) Gosstroy of the USSR
2. APPROVED AND INTRODUCED RESOLUTION State Committee USSR for construction of 18.06.84 N 87
3. Instead of GOST 12730.5-78, GOST 19426-74
4. Reference regulatory and technical documents
Point number, applications |
|
Appendix 4. |
|
1.1, Appendix 4 |
|
Appendix 4. |
|
5. Edition (June 2007) with a change in N 1, approved in June 1989 (IUS 11-89)
This standard applies to all types of concrete on hydraulic binders and establishes methods for determining the waterproof of concrete by testing samples.
1. General requirements
1.1. General requirements - according to GOST 12730.0 and in accordance with the requirements of this standard.
1.2. The height of the control samples of concrete depending on the greatest size of the aggregate grains is allowed to be assigned in accordance with Table 1.
Table 1
The greatest size of aggregate grains | The smallest height of the sample |
1.3. Mounting and sealing schemes of concrete samples in clippers are given in Appendix 1.
1.4. The end surfaces of the samples before the test are purified from the surface film of the cement stone and the sealing composition of the sealing composition with a metal brush or another tool.
2.1. Equipment and materials
- installation of any design that has no less than six sockets for fastening the samples and provides the possibility of supplying water to the lower end surface of the samples with increasing pressure, as well as the possibility of observing the state of the upper end surface of the samples;
- Water according to GOST 23732.
2.2. Preparation for the test
2.2.1. Made samples are stored in a normal hardening chamber at a temperature of (20 ± 2) ° C and relative humidity of at least 95%.
2.2.2. Before testing, samples are kept in the laboratory room during the day.
2.2.3. The diameter of the open end surfaces of concrete samples is at least 130 mm.
2.3. Testing
2.3.1. Samples in the clip are installed in the installation slots for the test and securely secure.
2.3.2. The water pressure is raised with steps of 0.2 MPa for 1-5 minutes and kept at each stage during the time specified in Table 2. The test is carried out until signs of water filtering in the form of droplets or wet spots appear on the upper end surface of the sample.
table 2
Sample height, mm | ||||
Standing time at each stage, h |
2.3.3. It is allowed to evaluate the waterproof of concrete with an accelerated method given in Appendix 4.
(Introduced additionally, meas. N 1).
2.4. Processing results
2.4.1. The waterproofability of each sample is estimated with the maximum water pressure, in which it has not yet been seeping through the sample.
2.4.2. The waterproof of the series of samples is estimated by the maximum water pressure, at which water seepage was not observed on four of the six samples.
2.4.3. The brand of concrete on waterproof is taking Table 3.
Table 3.
Waterproof of series of samples, MPa | ||||||
________________
2.4.4. Test results are logged in which the following graphs should be provided:
- marking of samples;
- age of concrete and test date;
- The value of the waterproof of individual samples and series of samples.
3.1. Equipment and materials
For testing apply:
- installation to determine the filtration coefficient with maximum test pressure of at least 1.3 MPa by Appendix 2;
- cylindrical forms (for the manufacture of concrete samples) internal diameter of 150 mm and a height of 150, 100, 50 and 30 mm;
- technical scales according to GOST 24104;
- Silica gel according to GOST 3956.
3.2. Preparation for the test
3.2.1. Made samples are stored in a normal hardening chamber at a temperature of (20 ± 2) ° C and relative humidity of at least 95%.
3.2.2. Before testing, concrete samples are kept in the laboratory room until the change in the sample mass per day is less than 0.1%.
3.2.3. Before starting the test, the samples must be tested for sealing and defectiveness by estimating the character of filtering inert gas supplied at an overpressure of 0.1-0.3 MPa to the bottom end of the sample, to the upper end of which is poured a layer of water.
With satisfactory sealing of the side surface of the sample in the clip and the absence of defects in it, the gas filtration is observed in the form of uniformly distributed bubbles passing through the water layer.
In case of unsatisfactory sealing of the side surface of the samples in the cable or in the presence of large defects, the gas filtering is observed as abundant local selection in defective places.
Defects of sealing of the side surface are eliminated by re-sealing samples. In the presence of separate large filtering channels, concrete samples are replaced.
3.2.4. Samples chosen from the design with a diameter of at least 50 mm, after the sealing of their side surfaces, tests are subjected to tests regardless of the presence of defects in them.
3.2.5. Water according to GOST 23732, used for testing, must be predeterized by boiling at least 1 h. The temperature of the water during the test period (20 ± 5) ° C.
3.3. Testing
3.3.1. The installation simultaneously experience six samples.
3.3.2. The lifting of the pressure of the disappeared water is carried out with steps of 0.2 MPa for 1-5 min with a shutter speed for 1 hour at each stage to the pressure at which signs of filtering appear in the form of separate drops.
3.3.3. Water (filtrate) pasted through the sample is collected in the receiving vessel.
3.3.4. Measuring the weight of the filtrate is carried out every 30 minutes and at least six times on each sample.
3.3.5. In the absence of a filtrate in the form of droplets for 96 hours, the amount of moisture passing through the sample is measured by absorbing it with silica gel or another sorbent in accordance with clause 3.3.4.
Silica gel must be pre-dried and placed in a closed vessel, which is tightly attached to the nipper for collecting the filtrate into the receiving vessel.
3.3.6. It is allowed to evaluate the concrete filtering coefficient to the accelerated method given in Appendix 3.
3.4. Processing results
3.4.1. The weight of the filtrate of a separate sample (H) is taken as the arithmetic average of the four largest values.
3.4.2. Filtration coefficient, cm / s, separate sample are determined by the formula
where - the weight of the filtrate, n;
- sample thickness, cm;
- sample area, cm;
- the test time of the sample, during which the weight of the filtrate is measured, C;
- overpressure Installation, MPa;
- coefficient taking into account the viscosity of water at various temperatures, TAKE Table 4.
Table 4.
Water temperature, ° С | |||
Coefficient |
Note. At the temperature of the water located in the interval between those specified in Table 4, the coefficient is accepted by interpolation.
3.4.3. When testing concrete samples with a diameter of less than 150 mm, chosen from structures, the filtering coefficient obtained by the calculated formula is multiplied by correction factor which is accepted according to Table.5.
Table 5.
Sample diameter, mm | ||||||
Correction factor |
3.4.4. To determine the filtering coefficient of the sample series, the filtering coefficients of individual samples of this series are positioned in the order of increasing their values \u200b\u200band use the average arithmetic value of the filtering coefficients of two medium samples (third and fourth).
3.4.5. The test results are logged in which the following columns should be provided:
- marking of samples;
- the weight of the filtrate;
- Filtering coefficient of each sample and series.
3.5. The obtained value of the filtration coefficient is compared with the brand of concrete on waterproof in accordance with Table 6.
Table 6.
Filtration coefficient, cm / s | Brand concrete on waterproof |
||||
________________
* Probably the error of the original. The designation of the brand of concrete on waterproof should be read: W2, W4, W6, W8, W10, W12, respectively (letter of Rosstandart dated 16.03.2017 N 3849th / 03). - Note database manufacturer.
The method of sealing the side surface of the sample by comprising samples with a set of alternating rubber and metal rings or a raised steel spring rubber ring | The method of sealing the side surface of the sample by pouring the gap between the samples and the rocked by special mastic | |||
The method of sealing the side surface of the sample
rubber hollow camera with overpressure in it
1 - sample concrete; 2 - test clip; 3 - mastic; 4 - a set of rubber and metal rings; 5 - rubber hollow camera; 6 - removable cover for water supply; 7 - Removable cap with a filtrate collection nozzle
Note. When determining waterproof, the "wet spot" method is removed by the cover 7.
1 - gas cylinder; 2 - pump; 3 - gearbox; 4 - valve; 5 - pressure gauge; 6 - pressure transmitter; 7 - water tank; 8 - elastic container with disheedic water; 9 - Spare container with disaded water; 10 - test nest; 11 - Filter Weight Meter
1. The minimum size of concrete samples for testing should be 150 mm.
2. Storage and preparation for testing concrete samples - in accordance with paragraphs.3.2.1 and 3.2.2 of this Standard.
3. Filtrate (see Chert.1 of this Annex) is installed on the bottom (when molding) the surface of the sample and is fixed (see Checks 2 of this Appendix).
FM-3 filtrent
1 - hydraulic pump; 2 - pump pen; 3 - work cylinder; 4 - working piston; 5 - Sealing washer; 6 - pressure gauge; 7 - Valve
Test concrete sample by filtrent
1 - filtrent; 2 - fastener; 3 - concrete sample
4. The water pressure in the filtometry chamber is raised to 10 MPa by rotating the pump handle and evaluate the pressure drop rate.
5. With a rapid drop in pressure and the impossibility of maintaining it by rotating the pump handle, the tests are stopped and the coefficient of concrete filtering is taken by the largest value specified in Table 6 of this standard (10 cm / s).
6. At a slow pressure drop, the position of the pump handle is noted, and the time corresponding to this point is taken for the beginning of the test.
The handle of the pump makes six complete revolutions, maintaining the pressure within (10 ± 0.5) MPa, and the tests are stopped. This time is taken after the end of the test.
According to the number of revolutions, the weight of water absorbed by concrete is determined, at the calculation, that one complete turnover of the pump handle is 9.63 · 10 N.
7. After the end of the test, the filtometter is removed from the sample, the wet surface is wiping with a rag and after 2-3 minutes the diameter of the darkened circle is measured. For calculation, the average arithmetic value of six measurements is taken.
8. The coefficient of filtering concrete, cm / s, is determined by the formula
where - the path of filtration, equal, cm;
- Time testing of samples, C;
- overpressure in the filtrent, MPa;
- Water absorption coefficient, N / cm.
Water absorption coefficient is determined by the formula
where - the weight of water absorbed by concrete, n;
- the volume of concrete saturated with water, see
The volume of concrete saturated with water is determined by the formula
9. The average value of the coefficient of concrete filtration is determined according to six tests in accordance with the requirements of claim 3.4.4 of this standard.
1.
General requirements - According to GOST 12730.0.
2. Selection of samples
2.1. The dimensions of the control samples are according to claim 1.2 of this standard. It is allowed to test samples-cubes with an edge of 150 mm long. The number of samples in the series is six.
2.2. Production of control samples - according to GOST 10180, storage and preparation of them to tests - according to claims 1.4 and 2.2 of this standard.
Note. When storing samples, the possibility of water from their surface should be excluded.
3. Equipment and materials
3.1. For testing use:
- a device of the type "Agama-2R" to determine the air permeability of concrete, the schematic diagram of which is shown on the drawback.
- Sealing mastic satisfying GOST 14791.
Schematic scheme Devices for determining the air permeability of the surface layers of concrete
1 - concrete sample; 2 - device camera; 3 - camera flange; 4 - vacuum sensor; 5 - Vacuumsos; 6 - sealing mastic; 7 - Valve
3.2. It is allowed to use other devices that meet the basic requirements:
- the width of the flange of the device chamber must be at least 25 mm;
- the initial pressure of pressed the flange of the chamber to the surface of the sample concrete should be at least 0.05 MPa;
- the initial level of vacuum pressure generated inside the chamber must be at least 0.064 MPa;
- the internal cavity of the chamber of the device must be at least 180 cm;
- When installing and sealing the device on the surface of an impermeable material (plexiglass according to GOST 9784, etc.), the drop in vacuum pressure should not exceed 0.002 MPa for 1 h.
4. Test preparation
4.1. The waterproof of concrete is determined by Table 7 or, if it is impossible to use the table, according to the experimentally installed calibration dependence.
Table 7.
Beton air permeability parameter, cm / s | Concrete resistance penetrating air, C / cm | Brand concrete on waterproof |
0,105-0,0728 | ||
0,0727-0,0510 | ||
0,0509-0,0345 | ||
0,0344-0,0238 | ||
0,0237-0,0164 | ||
0,0163-0,0113 | ||
0,0112-0,0077 |
4.2. Checking the possibility of using Table 7 is carried out in accordance with PP.7.1 and 7.2. Establishing a graduation dependence - according to PP.7.3-7.6.
4.3. Checking the possibility of using the values \u200b\u200bof Table 7 is carried out before the use of the present accelerated method and every time the type and quality of cement used, additives and aggregates are changed.
4.4. Before conducting the test, the device is checked for tightness in accordance with the instruction manual.
5. Testing
5.1. When testing sealing mastic, a harness with a diameter of at least 6 mm is laid on the camera flange by its midline and connect ends. The chamber flange is installed on the lower (under the formation conditions) the surface of the sample and in the chamber cavity creates a vacuum of at least 0.064 MPa.
5.2. In accordance with the instructions for the operation of the device, the value of the air permeability parameter of the concrete (cm / s) is determined for each sample or the reverse of the resistance of the concrete penetration (Cm).
6. Processing results
6.1. The obtained values \u200b\u200b() of concrete samples are recorded in the order of them increase and determine the arithmetic value () of two medium samples (third and fourth) as a parameter characterizing the air permeability of concrete in the series.
6.2. Table 7 or installed calibration dependences determine the concrete brand for waterproof () corresponding to the value obtained or. At the same time, as a brand of concrete on waterproof, when using calibration dependences, the value calculated by formula (1) or (2) for this value () and rounded to the nearest even number is taken.
7. Checking the possibility of using Table 7 and the establishment of calibration dependence
7.1. Check are carried out in the following sequence:
- according to PP.2.2, 5.1, 5.2 of this application are manufactured and experiencing one series of samples from concrete of one of the controlled compositions;
- determine the value (or) for this series of samples and the corresponding to it according to the table.7 brand of concrete on waterproof;
- The same series of samples are tested in Section.2 of this standard and determine the brand of concrete on waterproof "on the wet stain".
7.2. Table 7 can be used if the value of the concrete brand on waterproof is different from the table received by no more than one brand.
7.3. If the requirement of paragraph 7.2 is not performed (Table 7 cannot be used), to determine the brand of concrete on waterproof, the calibration addiction "" or "is used:
where and - the coefficients determined by paragraphs 7.4-7.5.
7.4. The coefficients are determined by the test results of the sample series in accordance with paragraph 7.1 and two additional series of samples, also manufactured and tested according to claim 7.1.
In the manufacture of samples of one of these series, a concrete mixture with a water-cement ratio of 0.40-0.42, the second - 0.52-0.54 should be used. The ratios between the fillers and between cement and additives in these concrete mixtures should be the same as in the controlled composition.
7.5. The coefficients are calculated by the formulas:
where - the value or for individual sample series (, or ,,);
- values \u200b\u200bfor separate series (, or) brand concrete on waterproof.
8. An example of establishing and using calibration dependence
8.1. To establish a calibration dependence at the ZBI factory according to claim 7.1, the main and two additional series of concrete samples were manufactured and tested. Test results are given in graphs 2 and 3 Table 8. With further control of the quality of concrete, various compositions prepared from the same materials as the samples of the specified series were manufactured and three series of samples were tested according to paragraphs 5.1 and 5.2, the average values \u200b\u200bof the air permeability parameter of which are indicated in column 2 Table 9. It is necessary to determine the brand of concrete on waterproof for each of these series.
8.2. Sequence of data processing for finding coefficients and is shown in Table 8.
Table 8.
Index series | |||||
8.3. By equation (1), the corresponding calibration dependence is:
Table 9.
Number series | (by equation (5) | |||
8.4. Substituting in equation (5) values \u200b\u200bfor Series 3-5 (graph 3 Table 9), we obtain the values \u200b\u200bgiven in column 4 Table 9. County, in accordance with paragraph 6.2 of this Annex, these values \u200b\u200bto the nearest even number, we determine the desired brands of concrete on the waterproof, indicated in column 5 Table 9.
Appendix 4. (Entered additionally, meas. N 1).
Electronic document text
prepared Codex JSC and drilled by:
official edition
Concretes. Methods of determination
density, humidity, water absorption,
porosity and waterproof:
Sat Gostov. GOST 12730.0-GOST 12730.5. -
M.: Starotinform, 2007
To lay the foundation, make a foundation or just pour a concrete track from home to the gate you need to know the proportions, features and brands. In this article, we will look at the main characteristics on which brands differ. After reading the material, you will know how it is selected by waterproof, and what they differ among themselves.
Will help in learning a table and a schedule, with which the starting builder will also choose the desired option. The material is divided into different stamps, indicating their designations the ability to resist frost and water. Depending on the brand, the concrete can withstand different pressure, not passing fluid.
There are ten main stamps of waterproof, which are regulated in GOST 26633. Belonging to a particular brand is indicated by the letter "W" and a certain number. If the letter remains unchanged, then the figure shows how much water pressure can withstand a specific type of concrete solution. A concrete cylinder with a height of 15 centimeters is taken as a basis.
There are direct and indirect properties of a solution to interact with liquid. Waterproof and filtering belong to the direct properties of a concrete solution. Indirect properties are water absorption and the ratio of cement to water. Of all 4 parameters, the main and, accordingly, indicative is the first, that is, water resistance.
The remaining indicators are considered additional for buyers or those engaged in construction. But these coefficients are important in the process of manufacturing concrete, as well as for scientific purposes.
Consideration of the three main stamps will help to navigate in the properties of concrete solutions:
In the intervals between these brands there are additional. Calculations are perfectly shown than different waterproof stamps differ.
Starting with the W4 brand, which has a normal fluid permeability indicator. Such a solution will absorb a normal amount of moisture, so it is not recommended to use it in works where low waterproofing. Below W4 is the W2 brand concrete, which absorbs even more water. Accordingly, W2 characterizes a mixture of low quality.
The W6 mixture has a reduced fluid permeability. This is a universal composition, as it absorbs less water than W4. It is the W6 most often used in large-scale construction work. But between W4 andW6 there is no intermediate grades.
W8 brand solutions have low permeability. Such a concrete absorbs about 4% of the whole mass. Concrete with labeling W8 is already significantly different in price from W6. Next go W10, W12 ... W20. The higher the digit, the less permeability. The W20 solution is the most resistant to water, but choose such a concrete for private purposes or for large and important projects.
The choice of a suitable brand is sometimes complicated, as they are ten. Obviously, it is not recommended to buy W2, as it is worth using it only in places where there is no moisture at all. The following tips will help you decide on the choice:
Next to "W" is the letter "F" with a specific digit, which indicates the coefficient of frost resistance. Today, concrete mixes with a coefficient of 25 to 1000 are produced. The numbers in the frost-resistance coefficient show how many frozen-size cycles are able to withstand the mixture. Simple words - This is the number of times of transitions from a frostbed state into frozen and back, which can withstand the construction of a concrete solution.
To better understand the characteristics of the frost resistance, it is worth considering the foundation of the house for example. The design constantly absorbs groundwater. Microscopic pores of the material are filled with liquid and remain there. After freezing, water expands these pores, as a result of which microcracks appear. Each subsequent freezing entails the expansion of these cracks.
In construction, waterproofing has long been used, which does not allow to fall into micropores the main amount of water. Various additives contribute to an increase in the frost resistance parameter (for example, air ducts). But they have and minus - decrease in the strength of the mixture. Hydrophobic cement allows you to achieve optimal frost resistance of a concrete solution.
Below are some tips to help choose the desired concrete solution:
Graduation of concrete brands for frost resistance and waterproof Updated: February 26, 2018 by the author: zoomfund
05.10.2015
