What is the compaction coefficient of sand? Technological map for leveling and compaction of pgs Compaction coefficient of sand-gravel mixture snip.

The compaction coefficient of any bulk material shows how much its volume can be reduced with the same mass due to compaction or natural shrinkage. This indicator is used to determine the amount of filler both during purchase and during the construction process itself. Since the bulk weight of crushed stone of any fraction will increase after compaction, it is necessary to immediately lay down a supply of material. And in order not to purchase too much, a correction factor will come in handy.

Compaction coefficient (K y) – important indicator, which is needed not only for correct formation ordering materials. Knowing this parameter for the selected fraction, it is possible to predict further shrinkage of the gravel layer after loading it building structures, as well as the stability of the objects themselves.

Since the compaction coefficient represents the degree of volume reduction, it varies under the influence of several factors:

1. Loading method and parameters (for example, from what height is backfilling performed).

2. Features of transport and the duration of the journey - after all, even in a stationary mass, gradual compaction occurs when it sags under own weight.

3. Fractions of crushed stone and grain contents of smaller size than the lower limit of a specific class.

4. Flakiness - needle-shaped stones do not give as much sediment as cuboid ones.

The strength of concrete structures, building foundations and road surfaces subsequently depends on how accurately the degree of compaction was determined.

However, do not forget that compaction on the site is sometimes carried out only on the top layer, and in this case calculated coefficient does not quite correspond to the actual shrinkage of the pillow. Home craftsmen and semi-professional construction teams from neighboring countries are especially guilty of this. Although, according to technology requirements, each layer of backfill must be rolled and checked separately.

Another nuance - the degree of compaction is calculated for a mass that is compressed without lateral expansion, that is, it is limited by the walls and cannot spread out. At the site, such conditions for backfilling any fraction of crushed stone are not always created, so a small error will remain. Take this into account when calculating the settlement of large structures.

Sealing during transport

Finding some standard compressibility value is not so easy - too many factors influence it, as we discussed above. The crushed stone compaction coefficient can be indicated by the supplier in the accompanying documents, although GOST 8267-93 does not directly require this. But transporting gravel, especially large quantities, reveals a significant difference in volumes when loading and at the final point of delivery of the material. Therefore, an adjustment factor that takes into account its compaction must be included in the contract and monitored at the collection point.

The only mention from the current GOST is that the declared indicator, regardless of the fraction, should not exceed 1.1. Suppliers, of course, know this and try to keep a small supply so that there are no returns.

The measurement method is often used during acceptance, when crushed stone for construction is brought to the site, because it is ordered not in tons, but in cubic meters. When the transport arrives, the loaded body must be measured from the inside with a tape measure to calculate the volume of gravel delivered, and then multiply it by a factor of 1.1. This will allow you to roughly determine how many cubes were put into the machine before shipping. If the figure obtained taking into account the compaction is less than that indicated in the accompanying documents, it means that the car was underloaded. Equal or greater - you can command unloading.

Compaction on site

The above figure is taken into account only for transportation. Under construction site conditions, where crushed stone is compacted artificially and using heavy machines (vibrating plate, roller), this coefficient can increase to 1.52. And the performers need to know the shrinkage of the gravel backfill for sure.

Typically the required parameter is specified in project documentation. But when the exact value is not needed, they use average indicators from SNiP 3.06.03-85:

• For durable crushed stone of fraction 40-70, a compaction of 1.25-1.3 is given (if its grade is not lower than M800).
• For rocks with a strength of up to M600 - from 1.3 to 1.5.

For small and medium size classes of 5-20 and 20-40 mm, these indicators are not established, since they are more often used only when decluttering the upper load-bearing layer of grains 40-70.

Laboratory research

The compaction coefficient is calculated based on laboratory test data, where the mass is compacted and tested on various devices. There are methods here:

1. Substitution of volumes (GOST 28514-90).

2. Standard layer-by-layer compaction of crushed stone (GOST 22733-2002).

3. Express methods using one of three types of density meters: static, water balloon or dynamic.

Results can be obtained immediately or after 1-4 days, depending on the study chosen. One sample for a standard test will cost 2,500 rubles, and at least five of them will be needed in total. If data is needed during the day, express methods are used based on the results of selecting at least 10 points (850 rubles for each). Plus you will have to pay for the departure of a laboratory assistant - about 3 thousand more. But during the construction of large projects it is impossible to do without accurate data, and even more so without official documents confirming the contractor’s compliance with the project requirements.

How to find out the degree of compaction yourself?

IN field conditions and for the needs of private construction, it will also be possible to determine the required coefficient for each size: 5-20, 20-40, 40-70. But to do this, you first need to know their bulk density. It varies depending on the mineralogical composition, although slightly. Crushed stone fractions have a much greater influence on the volumetric weight. For calculations, you can use averaged data:

Fractions, mm	Bulk density, kg/m3
	Granite	Gravel
0-5	1500	—
5-10	1430	1410
5-20	1400	1390
20-40	1380	1370
40-70	1350	1340

More accurate density data for a specific fraction is determined in the laboratory. Or by weighing a known volume of building rubble, followed by a simple calculation:

• Bulk weight = mass/volume.

After this, the mixture is rolled to the state in which it will be used on site and measured with a tape measure. The calculation is made again using the above formula, and as a result, two different densities are obtained - before and after compaction. By dividing both numbers, we find out the compaction coefficient specifically for this material. If the sample weights are the same, you can simply find the ratio of the two volumes - the result will be the same.

Please note: if the indicator after compaction is divided by the initial density, the answer will be greater than one - in fact, this is the material reserve factor for compaction. It is used in construction if the final parameters of the gravel bed are known and it is necessary to determine how much crushed stone of the selected fraction to order. When calculated back, the result is a value less than one. But these numbers are equivalent and when making calculations it is only important not to get confused which one to take.

The compaction coefficient must be determined and taken into account not only in narrowly focused areas of construction. Professionals and ordinary workers performing standard procedures for using sand are constantly faced with the need to determine the coefficient.

The compaction coefficient is actively used to determine the volume of bulk materials, in particular sand,
but also applies to gravel and soil. Most exact method Determining compaction is a weight method.

Wide practical use was not found due to the inaccessibility of equipment for weighing large volumes of material or the lack of sufficiently accurate indicators. Alternative option coefficient output – volumetric accounting.

Its only drawback is the need to determine compaction at different stages. This is how the coefficient is calculated immediately after production, during warehousing, during transportation (relevant for road deliveries) and directly at the end consumer.

Factors and properties of construction sand

The compaction coefficient is the dependence of the density, that is, the mass of a certain volume, of a controlled sample to the reference standard.

It is worth considering that all types of mechanical, external seals can only affect upper layer material.

The main types and methods of compaction and their effect on the upper layers of soil are presented in the table.

To determine the volume of backfill material, the relative compaction coefficient must be taken into account. This is due to change physical properties pit after digging out the sand.

When pouring a foundation you need to know correct proportions sand and cement. By going through, familiarize yourself with the proportions of cement and sand for the foundation.

Cement is a special bulk material, which in its composition is a mineral powder. about different grades of cement and their application.

With the help of plaster, the thickness of the walls is increased, which increases their strength. find out how long it takes for the plaster to dry.

P = ((m – m1)*Pв) / m-m1+m2-m3, Where:

• m – mass of the pycnometer when filled with sand, g;
• m1 – weight of an empty pycnometer, g;
• m2 – mass with distilled water, g;
• m3 – weight of the pycnometer with the addition of distilled water and sand, after getting rid of air bubbles
• Pv – water density

In this case, several measurements are taken based on the number of samples provided for testing. The results should not differ by more than 0.02 g/cm3. If the received data is large, the arithmetic average is displayed.

Estimates and calculations of materials and their coefficients are the main component of the construction of any objects, as it helps to understand the quantity required material, and accordingly costs.

To correctly draw up an estimate, you need to know the density of the sand; for this, information provided by the manufacturer is used, based on surveys and the relative compaction coefficient upon delivery.

What causes the level of the bulk mixture and the degree of compaction to change?

The sand passes through a tamper, not necessarily a special one, perhaps during the moving process. It is quite difficult to calculate the amount of material obtained at the output, taking into account all the variable indicators. For an accurate calculation it is necessary to know all the effects and manipulations carried out with sand.

The final coefficient and degree of compaction depends on various factors:

• method of transportation, the more mechanical contact with irregularities, the stronger the compaction;
• route duration, information available to the consumer;
• presence of damage from mechanical influences;
• amount of impurities. In any case, foreign components in the sand give it more or less weight. The purer the sand, the closer the density value is to the reference value;
• the amount of moisture that has entered.

Immediately after purchasing a batch of sand, it should be checked.

What samples are taken to determine the bulk density of sand for construction?

You need to take samples:

• for a batch of less than 350 tons - 10 samples;
• for a batch of 350-700 tons – 10-15 samples;
• when ordering above 700 tons - 20 samples.

Take the resulting samples to a research institution for examination and comparison of quality with regulatory documents.

Conclusion

The required density depends greatly on the type of work. Basically, compaction is necessary to form a foundation, backfill trenches, create a cushion for roadbed etc. It is necessary to take into account the quality of compaction; each type of work has different requirements to compaction.

In construction highways A roller is often used; in places difficult to reach for transport, a vibrating plate of varying power is used.

So, to determine the final amount of material, you need to set the compaction coefficient on the surface during compaction; this ratio is indicated by the manufacturer of the compaction equipment.

Always the relative density coefficient is taken into account, since soil and sand tend to change their indicators based on the level of humidity, type of sand, fraction and other indicators.

Routing designed for leveling and compacting bulk ASG when performing work on the construction of the site's topography.

1.2. Organization and technology of work execution

Preparatory operations include: geodetic layout of the planning contours and the zero line with the installation of alignment signs and benchmarks;

implementation of measures to protect the planned territory from the influx of surface water;

site lighting device;

installation of temporary access earth-carrying roads.

The main operations include:

construction of temporary earth-carrying roads within the planning area;

development of soil into a leveling embankment;

filling the leveling embankment with ASG, leveling the ASG, moistening or drying in case of excess moisture and compacting the ASG.

Finishing operations include:

layout of the site and slopes of the excavation, slopes and top of the embankment.

Schemes of work execution are shown on sheets 6, 7, 8 of the graphic part.

When performing vertical grading work, the soil from the grading excavation is partially moved into the grading embankment.

The development of soft soil and loosened rock inclusions of the leveling excavation is carried out with a B-10 bulldozer according to a tiered-trench scheme with intermediate accumulation of ASG. The entire excavation is divided in depth into several tiers, each of which, in turn, is divided into 3 layers of 0.10 - 0.15 m. The ASG in each tier is developed in trenches 3.2 m wide, and dividing walls (lintels) The ASG between the trenches is leveled with a bulldozer afterwards.

During the first penetration, moving towards the embankment, the bulldozer fills the ASG into the intermediate roller; during the second and third penetrations of the bulldozer, the intermediate roller is accumulated. Then the resulting large shaft of the ASG collides downhill into the backfilled embankment at one time. Similarly, work is being carried out to develop the ASG of all three layers in the trench of each tier. The development of ASG walls (lintels) left between trenches is carried out after the development of ASG in adjacent trenches. The ASG transported into the embankment is laid and leveled in layers 0.35 m thick.

Before the start of the work of the bulldozer that develops the ASG, the frozen soil is loosened with a mounted ripper. Loosening is carried out crosswise in two mutually perpendicular directions. First, longitudinal cuts are made to a depth of 0.30 m with a loosening step of 0.50 m, and then transverse cuts are made perpendicular to the longitudinal cuts to a depth of 0.30 m with a loosening step of 0.60 m. In this case, the effective loosening depth is 0.20 m The depth and loosening step are determined on site experimentally.

The leveling embankment is divided by area into two maps, where the following operations alternate in the technological sequence:

dumping and leveling of ASG with a bulldozer;

moistening of PGS;

standing and compacting the ASG with a Dynapac CA4000PD roller.

The ASG moved into the embankment by a bulldozer is leveled by the same bulldozer in circular penetrations when moving from the edges of the embankment to its middle. Bulldozer passes are made with an overlap of the previous penetration by 0.30 m. The ASG is leveled with a layer of 0.35 m. Before rolling each layer of the ASG, it is moistened (if necessary) with a PM-130B watering machine. Watering is carried out depending on the required moisture in several stages. Each subsequent pass of the watering machine is carried out after the PGS has absorbed water from the irrigation of the previous pass.

Compaction of the ASG must be carried out at an optimal moisture content in the ASG. Rolling of the ASG is carried out from the edges of the card to its middle. The movement of the roller is carried out with an overlap of the trace of the previous pass by 0.30 m. The first penetration of the roller is carried out at a distance of 3.00 m from the edge of the embankment, and then the edge of the embankment is rolled. After rolling the edges of the embankment, rolling continues with circular passes of the roller in the direction from the edges of the embankment to its middle.

Magnitude optimal humidity ASG, required amount of water for additional humidification, required amount roller passes along one track and the thickness of the layer being laid is determined at the work site by trial rolling.

During the process of work on each layer of ASG, its compaction is monitored by taking samples by a field soil laboratory.

For the movement of dump trucks, it is planned to construct earth-carrying roads made of slag 0.30 m thick. The slag brought by dump trucks is leveled by a B-10 bulldozer and compacted with a roller.

Earth hauling roads along which ASG is transported by dump trucks must be constantly maintained in good condition.

Schemes for laying ASG with a bulldozer

a - “from myself”; b - “to yourself”; c - “in separate heaps”; g - “half-press”; d - “press”

1.3. Compacting ASG with a Dynapac CA4000PD roller

Before compacting the ASG, it is necessary to deliver to the site and test the soil-compacting mechanisms, equipment and devices necessary to perform the work on compacting the ASG, and complete the preparation of the work front.

On large areas When performing work on the vertical planning of the territory, the roller movement pattern should be used in a closed circle. On embankments, where the possibility of turning the skating rink and making entrances is excluded, a shuttle traffic pattern should be used.

The number of roller passes along one lane should be approximately taken within 3-4, then the number of roller passes along one track is set by the construction laboratory in accordance with the required design density of the ASG.

Experimental soil compaction of embankments and backfills is carried out and as a result the following should be installed:

a) the thickness of the backfilled layers, the number of passes of compaction machines along one track, the duration of exposure of vibration and other organs to the ASG and other technological parameters that ensure the design density of the ASG;

b) the values ​​of indirect indicators of compaction quality that are subject to operational control.

Types and physical and mechanical characteristics ASG intended for the construction of embankments and the installation of backfills, and special requirements for them, the required degree of compaction (compaction coefficient - 0.95), the boundaries of parts of the embankment constructed from soils with different physical and mechanical characteristics are indicated in the project.

Scheme of work on soil compaction with rollers

a - when turning the skating rink on the site; b - when turning the skating rink to exit the site; 1 - axes, numbers and directions of roller passes; 2 - general direction of work on rolling; 3 - overlap of strips during rolling; 4 - embankment axis; 5-width of the embankment; 6 - roller turn; 1: t - steepness of embankment slopes

Scheme of organization of work on compaction of backfills

Compacting ASG when working in linear sections

Optimum humidity of ASG in necessary cases is achieved by moistening dry and, conversely, drying overly moistened ASG.

When compacting the ASG, the following conditions must be observed:

— the productivity of self-propelled rollers must correspond to the productivity of earth-moving and Vehicle;

— the thickness of the poured layer should not exceed the values ​​​​specified in technical specifications self-propelled rollers;

— each subsequent stroke of the roller, in order to avoid gaps in the compaction of the ASG, must overlap the previous one by 0.15 ... 0.25 m.

Compaction of the ASG by rolling should be carried out at a rational speed mode of operation of the rollers. The speeds of the roller are different, with the first and last two passes performed at low speeds (2 ... 2.5 km/h), and all intermediate moves at high speeds, but not exceeding 8 ... 10 km/h. With a rational speed mode of operation of the roller, its productivity approximately doubles.

If groundwater it is necessary to provide for the flow of water along the slope into the sumps with subsequent pumping out by pumps.

1.4. Operational Quality Control Scheme

The required quality of the compacted layer of ASG is ensured by the construction organization by implementing a set of technical, economic and organizational measures for effective control at all stages of the construction process.

Quality control of work should be carried out by specialists or special services that are part of construction organizations, or attracted from outside and equipped technical means, providing the necessary reliability and completeness of control.

Production quality control of soil compaction with self-propelled rollers should include:

— incoming control of documentation for materials, namely the availability of a document on the quality of the ASG containing information according to clause 4 of GOST 23735;

— operational control of individual construction processes or production operations;

— acceptance control of completed work.

During the incoming inspection of working documentation, its completeness and the sufficiency of the technical information contained in it for the execution of work must be checked.

The ASG used in the construction of embankments and backfill devices must meet the requirements of the project, relevant standards and technical specifications. Replacement of soils provided for by the design that are part of the structure being constructed or its foundation is permitted only in agreement with the design organization and the customer. Soil delivered to the construction site, intended for vertical leveling, backfilling of excavation pits, backfilling of road trenches, etc., must have a conclusion on sanitary-ecological and radiation inspection.

Incoming control includes:

— checking the granulometric composition of the soil;

— checking the wood, fibrous materials, rotting and easily compressible debris, as well as soluble salts contained in the soil for backfilling and construction of embankments;

— study and analysis of frozen lumps contained in the AGS, the size of solid inclusions, the presence of snow and ice;

— determination of the humidity of the ASG using a soil moisture meter “MG-44”

The results of incoming inspection must be entered into the “Logbook of incoming accounting and quality control of received parts, materials, structures and equipment.”

Operational control is carried out during construction processes and production operations and ensures the timely identification of defects and the adoption of measures to eliminate and prevent them. It is carried out by measuring method or technical inspection. The results of operational control are recorded in General magazines works and work production logs, geodetic control logs and other documents provided for by the quality management system in force in this organization.

During operational control, they check: compliance with the technology for performing work on compacting the ASG, their compliance with SNiP (compliance with the type of machines adopted in the work project, the humidity and thickness of the poured layer of ASG, its uniformity in the backfill, the density of the ASG in the layers of the embankment, etc.).

Acceptance control is control performed upon completion of work on compacting the ASG at the facility or its stages with the participation of the customer. Acceptance control consists of a random check of the compliance of the parameters of the completed elements of the earthen structure with the normative and design ones and assessment of the quality of the work performed. Acceptance earthworks should consist of checking:

— marks of the edges of the embankment and pit;

— dimensions of the embankment;

— steepness of slopes;

— degree of compaction of the ASG;

— quality of foundation soils.

When working on compaction of ASG, careful and systematic monitoring should be organized for:

— humidity of the compacted ASG using a soil moisture meter “MG-44”;

— thickness of the poured layer of ASG;

— the number of passages of soil-compacting mechanized means across the ground;

— the speed of movement of soil-compacting mechanized means.

The quality of soil compaction work is ensured by workers, foremen, foremen and work producers. The main responsibility of the foreman, foreman and foreman is to ensure High Quality works in accordance with working drawings, work design, SNiP and technological conditions for production and acceptance of work.

Handover and acceptance of work is documented by inspection certificates hidden work, checking the quality of the seal based on test results performed by the laboratory with an attached test report. The certificates must contain a list of technical documentation on the basis of which the work was performed, data on checking the correctness of the compaction and the bearing capacity of the foundation, as well as a list of deficiencies indicating the time frame for their elimination.

Composition of controlled operations, deviations and control methods

Technical requirements	Limit deviations	Control (method and volume)
1	2	3
1. Humidity of the compacted ASG	Must be within the limits established by the project	Measuring, according to project instructions
2.Surface seal:
a) average density of compacted soil over the received area	The same, not below the design level. It is allowed to reduce the density of dry soil by 0.05 t/m 3 in no more than 10% of determinations	The same, according to the design instructions, and in the absence of instructions, one point per 300 m 2 of compacted area with measurements within the entire compacted thickness every 0.25 m in depth for a compacted layer thickness of up to 1 m and every 0.5 m for greater thickness; the number of samples at each point is at least two
b) the magnitude of the decrease in the surface of the ASG (failure) during compaction with heavy rammers	Should not exceed that established during experimental compaction	Measuring, one determination per 300 m 2 of compacted area

Based on the results of the acceptance inspection, a documented decision is made on the suitability of the compacted soil for subsequent work.

1.5. Control of embankment compaction using the cutting ring method

The main control over the compaction of the embankment during the work process is carried out by comparing the volumetric weight of the soil skeleton taken from the embankment (g sk.), with optimal density (g sk. op.).

Sampling and determination of the volumetric weight of the soil skeleton in the embankment is carried out using a soil sampler, consisting of a lower part with a cutting ring and a hammer.

Soil selector

a - lower part of the soil sampler; b — cutting ring (separately); c - striker with movable load

When taking a soil sample, a soil sampler is placed on its cleaned surface in assembled form and hammer it into the ground with a drummer. Then the cover and intermediate ring of the lower part of the sampler are removed, the cutting ring is dug in, carefully removed along with the soil, the soil is cut off with a knife flush with the lower and upper edges of the ring. The ring with soil is weighed with an accuracy of one gram and the volumetric weight of wet soil in the embankment is determined by the formula:

Where G 1—ring mass, g;

G 2 — mass of the ring with soil, g;

V— ring crimp, cm 3.

This test is performed three times.

Also, the moisture content of the tested soil sample is determined three times by drying a sample of 15 - 20 g taken from each ring with soil to a constant weight.

The volumetric weight of the embankment soil skeleton is determined by the formula:

Where Wow. — gravimetric humidity soil in fractions of a unit.

The resulting volumetric weight of the skeleton in the embankment is compared with the optimal density of the same soil. Coefficient TO, characterizing the degree of soil compaction in the embankment, is determined by the formula:

1.6. Compaction control using soil moisture meter "MG-44"

PURPOSE

The electronic digital humidity meter “MG-44” (hereinafter referred to as the device) is designed to measure the relative humidity of the soil using a sensitive radio frequency sensor.

Humidity is determined using an indirect measurement method based on the dependence of the dielectric properties of the medium on its humidity. An increase in the dielectric constant of the test sample, at a constant temperature, indicates an increase in the water content in the material.

The device is intended for operation in areas with temperate climates. In terms of protection from exposure environment, the device has a conventional design. In the ambient air at the installation site of the device, the presence of aggressive vapors and gases and vapors within limits is allowed sanitary standards, according to the standards SN-245-71.

TECHNICAL DATA

Range of relative soil humidity measured by the device, %: 1-100

Limit of the main absolute error in the entire humidity measurement range, %: ±1 (90% of measurements fit within the specified error).

Time to establish operating mode, s: 3

Time of a single measurement, sec. no more than: 3

The device is powered from an internal source +-10 direct current+9 volts.

The measured relative humidity is read using a liquid crystal indicator located on the front panel of the indicator device.

Overall dimensions of the indicator device, mm: 145´80´40

Sensor: electrode length - 50 mm, sensor body length - 140 mm, diameter - 10 mm

Weight, kg, no more: 0.3

Temperature of the analyzed soil: -20…+60°C.

Ambient temperature from -20 to +70°C.

The change in instrument readings from a change in ambient temperature for every 10°C relative to normal (20°C), ranging from +1°C to +40°C, does not exceed 0.2 of the basic absolute error.

Electric power consumption of the device, no more than 0.1 VA.

DEVICE AND OPERATION

The general operating principle of the device is as follows:

The sensor emits a directed high-frequency electromagnetic wave, part of which is absorbed by water molecules as it propagates through the substance, and part of which is reflected in the direction of the sensor. By measuring the reflection coefficient of a wave from a substance, which is directly proportional to the water content, we display the relative humidity value on the indicator.

MEASUREMENT PROCEDURE.

When measuring, immerse the electrode in the ground.

Turn on the device with the button located on the left of the body.

On the display you will see: in the first line the name of the product first in the list of calibrations, in the second from the left - the humidity value in %: “H = ....%”, on the right is the battery charge indicator. By pressing the “Left” arrow button, you go to the list calibrations stored in the device’s memory. Using the “Left”, “Right” buttons, select the line you need, press “Enter”, and the name of the product and its humidity will appear on the display.

You can make an amendment (within + - 5% in increments of 0.1%) to the device readings if the device readings and the product humidity obtained by the laboratory air-thermal method do not match. To do this, follow this procedure:

Immerse the sensor in soil whose moisture content is precisely known.

Press the power button

Select the line you need from the list.

Press Enter.

Press and hold the Up arrow button until the correction value in % appears on the second line of the display between the humidity reading and the battery charge symbol. For example:

Release the Up arrow button.

Use the buttons to set the desired correction. Simultaneously with making the correction, the humidity value, already corrected, changes at the bottom left. Having set the desired value, press “Enter”, and the correction value will disappear from the display.

The shape of the calibration curve does not change when the correction is made. There is only a parallel transfer of the characteristics “down” - “up” within +_ 5%.

The correction for each of the 99 channels is different and independent.

Calibration

You can independently enter into the processor memory and create any calibration curve for any type of soil.

1. Press and hold the Up button

2. Without releasing the Up button, press and hold the power button all the time

On the display you will see:

Release the Up Arrow Button

You must dial the calibration access code: 2-0-0-3

You do this procedure using the “Left” buttons (dial from 1 to 9 and again from 1 to 9, each press increases the number by 1), “Right” (go to the next digit). By typing 2-0-0-3 , press “Enter”

3.On the display you will see:

U= ……V E= -.- -V

In the upper left corner is the current voltage value from the sensor. It changes depending on soil moisture. In the upper right is the voltage value already stored in the processor memory and corresponding to the soil moisture value in % entered in the line H=....%. If you see dashes in the upper right corner, it means that the humidity value in the lower left has not yet been assigned a voltage value.

Before entering a new calibration, the memory must be reset.

Press and hold the button until the display shows:

Release the button and the memory is free for calibration on this channel.

This erases all previously entered data for this channel.

Completely immerse the sensor electrode in soil whose moisture content is accurately known.

Press the Left or Right arrow button

In the second line, the symbol Н=0.0% will be enclosed on both sides in triangular cursors.

Dial desired value humidity (humidity of the calibrated sample into which the electrode is inserted (in the line H = ....%)) using the “Left” and “Right” arrows.

Press Enter. One point entered. At the same time, in the upper right corner of the indicator in line E = .... The sensor voltage value stored in the permanent memory will appear. The minimum number of points is two. Maximum – 99. The shape of the calibration characteristic is straight. Humidity values ​​of 0.99 and 100 cannot be entered. Enter 1 and 98.

Insert the sensor electrodes into another sample with a different humidity (known) and repeat the procedure.

Accurate calibration is possible if you calibrate the device using samples whose moisture content lies at the edges of the range of interest to you.

For soil it is usually 12 -70%%. Only whole numbers are entered. Humidity obtained by the air-thermal method must be rounded to whole numbers. The processor itself will build a calibration curve and display the tenths.

If you want to erase not the entire calibration from memory, but only individual points, perform the following procedure:

Enter calibration mode and start pressing the "Left" button successively

When you get to a point stored in memory, in the upper line on the right in the expression E = -, - - V, instead of dashes, a voltage value appears, which corresponds to the humidity value in %, typed in the bottom line (H = ....%). If you want to erase this point without erasing the rest of the information, press for now in the expression E = ….,…. V no dashes will appear instead of numbers. Release the button immediately so as not to erase the remaining dots, indicating the edges of the full operating range.

You can type (or change) any calibration name into any of the 99 lines, using the Latin and Russian alphabets and Arabic numerals:

Turn on the device

Use the “Left” and “Right” buttons to select the desired line.

Press and hold the “Enter” button until two lines appear:

One with alphabets and numbers, the other with the name you typed.

In the alphabets line, use the “Right”, “Left” buttons to select a letter or number (the character ready to be entered into the name line is enclosed between two arrows), press “Enter” and the symbol is saved on the name line. Erase a previously typed word or erroneous character using the “Up” button. One click - one erased character.

When you have completely typed the name of the calibration, press “Enter” until you return to the list of calibrations with the name already saved.

1.7. Occupational safety and health

General instructions for safety during excavation work are given in the technological map for the development of excavations.

Work areas in populated areas or on the territory of the organization must be fenced off to prevent access by unauthorized persons. Specifications GOST 23407-78 was established for the installation of inventory fences.

A self-propelled roller must be equipped with sound and light signaling devices, the serviceability of which must be monitored by the driver. It is prohibited to work with faulty sound and light signaling devices or without them. Before the machine starts moving or when braking and stopping, the driver must give warning signals.

It is prohibited to work in the evening and at night in the absence of lighting or when the visibility of the work front is insufficient.

When working to compact soil with self-propelled rollers, the following is prohibited:

- work on faulty rollers;

- lubricate the roller while moving, troubleshoot problems, adjust the roller, enter and exit the roller cabin;

— leave the roller with the engine running;

— unauthorized persons should be in the skating rink cabin or in close proximity to it;

— be on the frame of the roller or between the rollers while they are moving;

— stand in front of the disk with the locking ring when inflating the tires;

— leave the rollers on a slope without placing stops under the rollers;

— turn on the vibrator when the vibratory roller is on hard ground or a solid foundation (concrete or stone).

When compacting soils at night, the machine must have side lights and headlights to illuminate the path of movement.

After finishing the work, the driver must place the machine in the place designated for its parking, turn off the engine, turn off the fuel supply, winter time Drain the water from the cooling system to prevent it from freezing, clean the machine from dirt and oil, tighten the bolted connections, and lubricate the rubbing parts. In addition, the driver must remove the starting devices, thereby eliminating any possibility of unauthorized persons starting the machine. When parked, the vehicle must be braked and the control levers placed in the neutral position. When handing over a shift, it is necessary to inform the shift worker about the condition of the machine and all detected faults.

When carrying out soil compaction work, measures must be taken to prevent machines from tipping over or spontaneously moving under the influence of wind or in the presence of a terrain slope. It is not allowed to use open fire to heat up machine components, or to work on machines with leaks in the fuel and oil systems.

When compacting soil with two or more self-propelled machines moving one after the other, the distance between them must be at least 10 m.

Moving, installing and operating a soil-compacting machine near an excavation with unreinforced slopes is permitted only beyond the limits established by the work design. In the absence of appropriate instructions in the work project, the horizontal distances from the base of the excavation slope to the nearest machine supports must correspond to those indicated in the table

Liked this.

When choosing crushed stone, it is important to take into account such an indicator as the compaction coefficient. This criterion shows how much the volume of material can be reduced while maintaining the same mass due to compaction or natural shrinkage. This indicator is used to determine the amount of aggregate, both during purchase and directly during the construction process.

Due to the fact that after compaction the bulk weight of crushed stone of any fraction will increase, it is necessary to immediately take into account the supply of material. And in order not to buy too much, a correction factor is needed.

The compaction coefficient (Ku) is a very important indicator, which is necessary not only for the correct ordering of materials, but also in order to provide for further shrinkage of the gravel layer after it is loaded with building structures. Moreover, knowing the compaction coefficient, it is possible to predict the stability of the construction projects themselves. Due to the fact that the compaction coefficient is, in fact, the degree of volume reduction, it can vary depending on 4 factors:

1. Loading method and parameters (for example, from what height the backfill is performed).
2. Features of the transport by which the material is delivered to the site, and the distance to the construction site - after all, even a stationary mass gradually becomes denser as a result of subsidence under its own weight.
3. Crushed stone fractions and grain contents are smaller than the lower limit of a specific crushed stone class.
4. Flakiness - needle-shaped stones shrink less than cuboid stones.

It should be remembered that the strength of concrete structures, building foundations and highways directly depends on the accuracy of determining the degree of compaction. However, we should also not forget that compaction on site is often performed only on the top layer, and in this case the calculated coefficient does not always correspond to the actual shrinkage of the base. This happens especially often when construction is carried out not by professionals, but by amateurs. In accordance with technology requirements, each layer of backfill must be rolled and checked separately.

Another parameter that must be taken into account is that the degree of compaction is calculated for a mass that is compressed without lateral expansion, that is, limited by the walls, which prevents it from spreading. At the site, such conditions for backfilling any fraction of crushed stone are not always created, so a small error remains. This fact should be taken into account, first of all, when calculating the settlement of large structures.

Sealing during transport

It should be noted that finding a standard compressibility value is actually not easy, since too many factors influence it. (All of them are listed above). The supplier may indicate the crushed stone compaction coefficient in the accompanying documentation, although GOST 8267-93 does not directly require this. However, when transporting gravel, especially large quantities, there are often significant differences in volumes when loading and at the construction site where it was delivered. Therefore, the correction factor, which takes into account the compaction of crushed stone, must be included in the contract and controlled at the reception point. The only mention in the current GOST: the compaction coefficient, regardless of the fraction, should not be higher than 1.1. Suppliers are certainly aware of this, and in order to avoid returns, they try to keep a small supply. Measurements are often resorted to during acceptance, when crushed stone is delivered to the construction site, since it is ordered not in tons, but in cubic meters. To do this, the truck body with the crushed stone in it must be measured from the inside with a tape measure, then the volume of gravel delivered must be calculated, and then multiplied by a factor of 1.1. This calculation will allow you to approximately determine how many cubes were poured into the back of the truck before shipment. If the figure obtained taking into account the compaction is less than that indicated in the accompanying documents, it means that the car body was underloaded. Equal to or greater than that indicated in the documents, you can safely unload the crushed stone.

Compaction on site

Please note that the above figure - 1.1 - is taken into account only during transportation. At a construction site where crushed stone is compacted artificially, using a vibrating plate or roller, this coefficient can increase to 1.52. At the same time, performers need to know exactly the degree of shrinkage of the gravel backfill. Usually this parameter is listed in the design documentation. However, if there is no need for an exact value, use the average indicators specified in SNiP 3.06.03-85:

Crushed stone of fraction 40-70, as a rule, has a compaction of 1.25-1.3 (if its grade is not lower than M800). Up to M600 – from 1.3 to 1.5. For small and medium classes of 5-20 and 20-40 mm, these indicators have not been established, since they are often used only when clinching the upper load-bearing layer of grains 40-70.

Laboratory research

The compaction coefficient is usually calculated based on laboratory test data, during which a mass of crushed stone is compacted and tested on various devices. There are several methods here: volume replacement (GOST 28514-90); standard layer-by-layer compaction of crushed stone (GOST 22733-2002); express methods using one of three types of density meters: static, water balloon or dynamic.

Results are obtained either immediately or after 1-4 days, depending on which research method is chosen. The cost of one standard test sample is 2,500 rubles. In total, at least five such tests must be carried out. If data is needed urgently, for example, during the day, express methods are used based on the results of selecting at least 10 points. The cost of each point is 850 rubles. In addition, you will have to pay for a laboratory technician to travel to the site - about another 3 thousand rubles. However, it is impossible to do without accurate data during the construction of large projects. In addition, solid construction organization It is necessary to have official documents that confirm the contractor’s compliance with the project requirements.

Is it possible to find out the degree of compaction yourself?

Yes, the coefficient can be determined both in the field and for the needs of private construction. To do this, you must first find out the bulk density for each size: 5-20, 20-40, 40-70. It directly depends on the mineralogical composition of the material, but it is insignificant. Crushed stone fractions have a much greater influence on the volumetric weight. For calculations, you can use averaged data:

More accurate density data for a specific fraction of crushed stone can be determined in the laboratory or by weighing a known volume of building crushed stone, followed by a simple calculation:

Bulk weight = mass/volume.

After this, the mixture is rolled to the state in which it will be used on the site and measured with a tape measure. And then they again calculate the formula given above, resulting in 2 different densities - before and after compaction. By dividing both numbers, we obtain the compaction coefficient for a specific material. If the sample weights are the same, you can simply find the ratio of the two volumes - the result will be similar. It should be noted that if the indicator after compaction is divided by the initial density, then the number obtained in the answer will be greater than one - in fact, this is the material reserve factor for compaction. In construction, it is used if the final parameters of the gravel bed are known and for ordering it is necessary to determine the amount of crushed stone of the selected fraction. When calculated back, the result is a value less than one. However, these numbers are equivalent and when making calculations it is important to understand which one should be taken.

Crushed stone is a common construction material, which is obtained by crushing rock hard rock. Raw materials are extracted by blasting during quarrying. The rock is divided into appropriate fractions. In this case, the special compaction coefficient of crushed stone is important.

Granite is the most common, as its frost resistance is high and water absorption is low, which is so important for any building structure. The abrasion and strength of granite crushed stone meets the standards. Among the main fractions of crushed stone we can note: 5-15 mm, 5-20 mm, 5-40 mm, 20-40 mm, 40-70 mm. The most popular is crushed stone with a fraction of 5-20 mm; it can be used for various works:

• construction of foundations;
• production of ballast layers for highways and railway tracks;
• additive to construction mixtures.

The compaction of crushed stone depends on many indicators, including its characteristics. Should be considered:

1. The average density is 1.4-3 g/cm³ (when compaction is calculated, this parameter is taken as one of the main ones).
2. Flakiness determines the level of plane of the material.
3. All material is sorted into fractions.
4. Frost resistance.
5. Radioactivity level. For all work, you can use crushed stone of the 1st class, but the 2nd class can only be used for road work.

Based on such characteristics, a decision is made which material is suitable for a particular type of work.

Types of crushed stone and technical characteristics

Various crushed stones can be used for construction. Manufacturers offer different types of it, the properties of which differ from each other. Today, based on the type of raw material, crushed stone is usually divided into 4 large groups:

• gravel;
• granite;
• dolomite, i.e. limestone;
• secondary.

To make granite material, the appropriate rock is used. This is a non-metallic material that is obtained from hard rock. Granite is solidified magma that is very hard and difficult to process. Crushed stone of this type is manufactured in accordance with GOST 8267-93. The most popular is crushed stone having a fraction of 5/20 mm, as it can be used for a variety of works, including the manufacture of foundations, roads, platforms and other things.

Crushed gravel is a bulk construction material that is obtained by crushing stony rock or rock in quarries. The strength of the material is not as high as that of crushed granite, but its cost is lower, as is the background radiation. Today it is common to distinguish between two types of gravel:

• crushed type of crushed stone;
• gravel of river and sea origin.

According to the fraction, gravel is classified into 4 large groups: 3/10, 5/40, 5/20, 20/40 mm. The material is used for preparing various building mixtures as a filler; it is considered indispensable for mixing concrete, building foundations, and paths.

Limestone crushed stone is made from mountain sedimentary rock. As the name implies, the raw material is limestone. The main component is calcium carbonate, the cost of the material is one of the lowest.

The fractions of this crushed stone are divided into 3 large groups: 20/40, 5/20, 40/70 mm.

It is applicable to the glass industry, in the manufacture of small reinforced concrete structures, in the preparation of cement.

Recycled crushed stone has the lowest cost. It is made from construction waste, for example, asphalt, concrete, brick.

The advantage of crushed stone is its low cost, but in terms of its main characteristics it is much inferior to the other three types, therefore it is rarely used and only in cases where the strength of great importance does not have.

Return to contents

Compaction factor: purpose

The compaction coefficient is a special standard number determined by SNiP and GOST. This value shows how many times crushed stone can be compacted, i.e. reduce its external volume during compaction or transportation. The value is usually 1.05-1.52. According to existing standards, the compaction coefficient can be as follows:

• sand and gravel mixture - 1.2;
• construction sand - 1.15;
• expanded clay - 1.15;
• crushed gravel - 1.1;
• soil - 1.1 (1.4).

An example of determining the compaction coefficient of crushed stone or gravel can be given as follows:

1. It can be assumed that the mass density is 1.95 g/cm³; after compaction was carried out, the value became 1.88 g/cm³.
2. To determine the value, you need to divide the actual density level by the maximum, which will give a crushed stone compaction coefficient of 1.88/1.95=0.96.

It is necessary to take into account that the design data usually does not indicate the degree of compaction, but the so-called skeleton density, i.e. During calculations, it is necessary to take into account the level of humidity and other parameters of the building mixture.