ROAD TECHNICAL SPECIFICATION ÚT 2-2

2

ROAD TECHNICAL SPECIFICATION ÚT 2-2 .124

DEPARTMENT OF ROAD TRANSPORT OF THE MINISTRY OF ECONOMY AND TRANSPORT

Page number: 26 ÚT 2-2.124:2005

Measuring of Dynamic Compactness and Dynamic Bearing Capacity with Small Plate Light Falling Weight Deflectometer

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MAGYAR ÚTÜGYI TÁRSASÁG 2

Revised by the Hungarian Road Society

on the basis of the road specification ROAD 2-2.124:2003

Advisory board: under the direction of István Subert János Baksay, Ferenc Pszota, László Tárczy, Mária Vértes

Division of Public Road Maintenance and Administration:

Gábor Stoll head of division

Division of Road Construction: dr. Frigyes Törıcsik head of division Division of Road Design: László Keresztes head of division

Coordination Board: dr. Zsuzsanna Csorja Quality Management Board

Publication Board

The publication is managed by: PMS 2000 Engineering Company, dr. Mária Petıcz acting director

Made on the commission of the State Public Road Tec hnical and Information Public Company

Tutor: dr. Tibor Boromisza Head of the Department of Technical Regulation: Zoltán Vályi

Procurer’s Project Manager: János Tóth

Distributed by the Hungarian Road Society All rights reserved on any publication and copying

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Hereby, the Department of Road Transport of the Ministry of Economy and Transport issues the road specification “ÚT 2-2.124:2005 Dynamic compactness and bearing capacity measurement with small-plate l ight falling deflectometer” .

Subject of the specification: on-site determination of dynamic compactness and bearing capacity of earthworks, granulous reclaiming and protective layers as well as base layers with manual light falling deflectometer.

The measuring procedure is suitable for the testing of any fresh material layer or earthwork layer of a maximum grain size of 63 mm and a maximum thickness of some double of the disc diameter, without any binding agent and with a hydraulic binding agent. The testing procedure cannot be applied for neither bonded layers mixed with a binding agent (hydraulic or hot bitumenous) nor for frozen layers.

According to the agreement on the provision of public benefit services, the application of the road specification is obligatory for the maintainers of the national public roads both as clients and as for th eir own activities. During the execution of the construction, maintenance and operation tasks carried out thereby the road specification must be observed.

According to the agreement on their activities the maintainers of the national roads are obliged to apply the present road specif ication as from 1 May 2005.

The application of the road specification is recomm ended and reasonable in case of any local public road and private road that is not closed to public traffic.

With regard to the national public roads any deviation from the road specification is only allowed by exemption. One shall apply for any exemption from the specification at the Department of Road Transport of the Ministry of Economy and Transport. The application must be submitted to the State Public Road Technical and Information Public Company.

The present road specification annuls the road specification “ÚT 2-2.124:2003 Dynamic compactness and capacity measurement with l ight falling deflectometer”.

Budapest, 15 March 2005

Ministry of Economy and Transport Department of Road Transport

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CONTENT

1. TERMS OF APPLICATION ............................... ........................................................................................6

2. TERMINOLOGY ........................................................................................................................................6

2.1. Dynamic bearing capacity .................................................................................................................6

2.2. Dynamic (bearing capacity) modulus ................................................................................................6

2.3. Deflection (depression amplitude).....................................................................................................7

2.4. Bearing capacity measurement.........................................................................................................7

2.5. Static bearing capacity measurement ...............................................................................................7

2.6. Static bearing capacity modulus .......................................................................................................7

2.7. Dynamic compactness and bearing capacity measurement.............................................................7

2.8. Light falling deflectometer .................................................................................................................7

2.9. Gauge soundness test (own control) ................................................................................................7

2.10. Measurement data ........................................................................................................................7

2.11. Measuring result ...........................................................................................................................7

2.12. Measurement site .........................................................................................................................7

2.13. Dynamic compactness measurement...........................................................................................8

2.14. Relative compactness...................................................................................................................8

2.15. Moisture correction coefficient ......................................................................................................8

2.16. Dynamic compactness rate...........................................................................................................8

2.17. Drop ..............................................................................................................................................8

2.18. Sequence ......................................................................................................................................8

3. TESTING METHOD...................................................................................................................................8

4. TESTING INSTRUMENTS ........................................................................................................................9

4.1. Measuring instrument........................................................................................................................9

4.2. Accessories .....................................................................................................................................11

4.3. Sampling instruments......................................................................................................................11

4.4. Materials ..........................................................................................................................................11

4.5. Modes of the measuring instrument................................................................................................12

5. TESTS......................................................................................................................................................13

5.1. Preparation of the measurement site ..............................................................................................13

5.2. Preparation of the gauge for measurement ....................................................................................13

5.3. Dynamic bearing capacity measurement ........................................................................................14

5.4. Dynamic compactness and bearing capacity measurement...........................................................15

6. MEASURING RESULTS .................................. .......................................................................................15

6.1. Deflection, depression amplitude ....................................................................................................15

6.2. Dynamic bearing capacity modulus ................................................................................................16

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6.3. Dynamic compactness rate.............................................................................................................17

7. TEST REPORT........................................................................................................................................18

7.1. Content requirements......................................................................................................................18

ANNEX .............................................................................................................................................................20

M.1. Calibration of the light falling deflectometer ....................................................................................20

APPENDIX .......................................................................................................................................................22

F.1. Terms used in the calculations........................................................................................................22

F.2. Technical requirements ...................................................................................................................22

F.3. Calculation and application of the moisture correction coefficient ..................................................22

F.4. Demonstration of the calculations ...................................................................................................24

Calculation of dynamic moduli.....................................................................................................................25

Calculation of the moisture correction coefficient (Trw)................................................................................25

Calculation of the relative compactness rate...............................................................................................25

Referred Hungarian national standards and road specifications ................................................................26

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1. TERMS OF APPLICATION

By the commission of the falling bearing capacity deflectometers on the national road network dynamic measurements started along with the static measurements (ÚT 2-2.117 Dynamic bearing capacity measurement, ÚT 2-2.119 Bearing capacity measurement with light falling deflectometer). The KUAB-type hauled falling deflectometer is not or only after expensive preparatory works suitable for the determination of the bearing capacity of both earth-works and base layers. The KUAB device does not suit for the quick, non-destructive on-site test of the bearing capacity of the repair of small areas, soil- or base layer replacements or backfillings above the public utility, at the demolition of lined buildings, base layer etc. For this purpose the manual light falling deflectometer may be appropriate by which the requirements on both the testing circumstances and the device must be controlled, in accordance with the expectations.

The foreign and domestic measuring experience and comparative tests, which one can already consider as significant ones, showed that the dynamic bearing capacity modulus of the light falling bearing capacity measurement was more sensitive and could be used better in the construction practice than the E2 modulus of the static disc measurement stated in MSZ 2509-3.

The modulus of dynamic measurements can neither in the case of soils be directly correlated to the bearing capacity modulus of the static measurement; and thus, no general correlation can be given unitedly. The limit values on the type of the substance and on the conditions can be determined parallel to the E2 measurements, separately for all soil-types, granulous surface pavements. The first step of determining the soil- and material-type includes the representative site sampling. The laboratory testing of the material is a precondition for the compactness measurement; and furthermore, the bearing capacity measurement is recommended in each case when it is not possible to determine the type thereof on site.

The dynamic compactness measurement can be carried out by both the vibrating or falling compactness method. According to the present specification the dynamic gauge with a disc gauge of a diameter of 163 mm suits for the local compaction of the layer, in accordance with the Proctor-effort, and thereby, both the dynamic compactness rate and the dynamic bearing capacity can be determined with one gauge. With this method the simultaneous measurement of the two most important quality parameters can be ensured, thus, providing great help in the procedural quality control.

In the dynamic compactness and bearing capacity testing the homogeneity of the tested layer is a precondition; and during the evaluation of the results knowledge on both the thickness of the examined layer and the material(s) of the subordinate layer(s) may provide important information.

2. TERMINOLOGY

2.1. Dynamic bearing capacity

For the present specification it means the feature of either a granulous layer or earth-work with a thickness of a maximum of 30 cm, by which it is able to stand the short-time dynamic loading, under given soil-physical parameters (water content, grain distribution, internal friction).

2.2. Dynamic (bearing capacity) modulus

A parameter characterizing the bearing capacity which is calculated with the Boussinesq-formula from the depression amplitude emerging as an effect of a dynamic loading, besides a given impact number, considering the Poisson’s ratio and the diameter of the loading disc. Sign: Ed or Edvég, unit: MPa, N/mm2, or MN/m2.

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2.3. Deflection (depression amplitude)

A vertical displacement measured in a given point under defined loading circumstances (loading, loading duration) which characterizes the vertical deformation of the examined material layer during the dynamic measurement. Sign: s, 0.01 mm

2.4. Bearing capacity measurement

A procedural method on the bearing capacity measurement, based on theoretical considerations which is executed by the measurement of the deflection (deformation) emerging as an effect of the loading put on the surface of the layer.

2.5. Static bearing capacity measurement

Site examination procedure for determining the static bearing capacity modulus of the earth-work, the sub-soil or the surface pavement, in accordance with MSZ 2509-3, by gradual and slow loadings, during which a considerable part of the consolidation occurs.

2.6. Static bearing capacity modulus

Modulus determined through on-site testing according to MSZ 2509-3, by the Boussinesq-formula, with the fixed disc model multiplier, and calculated from the data of the the second pressure-deformation curve. Sign: E2, MPa, or N/mm2.

2.7. Dynamic compactness and bearing capacity measu rement

Site examination procedure based on theoretic considerations, for the determination of the dynamic bearing capacity modulus and the dynamic compactness rate through impacts, quick loading, with a gauge determined in the present specification.

2.8. Light falling deflectometer

A manual gauge determined in the present specification which suits for the determination of the dynamic compactness rate (Trd, %) and the dynamic bearing capacity modulus (Ed, MPa, N/mm2 or MN/m2), at which a suitable number of falling weights of a given mass are being dropped from a given height to a steel disc transmitting the loading.

2.9. Gauge soundness test (own control)

A procedure for determining whether the gauge is suitable for any measurements within the error limit in accordance with the present test instructions.

2.10. Measurement data

Deformation values derived from the acceleration measurement during the on-site measuring under given measuring circumstances, during the execution of one measuring sequence.

2.11. Measuring result

Value of a given tolerance formed from the measuring data under identified conditions, with a given confidence interval or measurement error, together with a dimensional unit.

2.12. Measurement site

A site assigned for measurement prepared in accordance with the testing requirements, where the measurement takes place.

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2.13. Dynamic compactness measurement

A testing method based on the volume change measurement, characterized by the depression amplitude, by which the site compaction is being carried out with an 18-impact sequence in accordance with the Proctor compacting effort.

2.14. Relative compactness

Ratio of the highest possible compactness reached by fixed compacting effort at a given measurement point, by a given water content and the original compaction phase, which is derived from the deformation curve of the compaction generating caused by the impacts. The relative compactness is always the quotient of the compactness rate and the moisture correction coefficient. Sign: TrE, %

2.15. Moisture correction coefficient

A dimensionless number less than or exactly 1.00 which is the quotient of the bulk density (ρdi) read for the natural water content (wt) at the point of measurement from the density curve determined by the modified Proctor-test and the highest dry density (ρdmax) defined during the Proctor-test. It is a value characterizing the material type that can be determined in advance with the laboratory soundness test, as a function of the water content change and that can be displayed in a tabular or graphical form. Sign: Trw

2.16. Dynamic compactness rate

The product of the relative compactness (TrE) and the moisture correction coefficient (Trw). In this case the relative compactness rate of the layer with a given moisture content is calculated for the highest possible compactness available at the optimal water content. Numerically it is a rate which coincides with the the compactness rate (Trp) determined through the isotopic compactness measurement in accordace with ÚT 2-3.103. Sign: Trd, %

2.17. Drop

The single drop of the falling weight of a light falling deflectometer, in a controlled manner. The depression amplitudes (sij) and the disc-speed (vij) measured in this moment are marked with the j = 1–3 index beside i = sequence. The depression amplitude of the first drop is: s01, mm.

2.18. Sequence

Three subsequent drops of the falling weight of the light falling deflectometer the average of which is also displayed by the gauge. The measured depression amplitudes (sij) and the disc speed (vij) are marked with the serial index i = 0–5. During the calculation of the results the average is being determined which is marked by letter „á

” next to the serial index. The average of the depression amplitudes of the second sequence is: s1á, mm.

3. TESTING METHOD

During the test a solid of a known mass is being dropped onto a rigid disc of a given diameter, via a buffer spring, from a given height. The vertical displacement arising from the dynamic loading, i.e. the depression amplitude is measured under the central point of the loading disc. In case of a falling weight of 10 kilogrammes and a dropping height of 72 cm some 7065 N dynamic loading power is transmitted onto the disc which results in a dynamic pressure (pdin) of 0.3 MPa, by a proper spring constant and a dial diameter of 163 mm. The falling weight and the dropping height must be chosen to the value required for the dynamic loading pressure, for each gauge, through the selection of both the given spring constant and the mass of the falling weight within the confidence interval.

From the second measuring sequence of the depression amplitudes characterizing the deformation one can determine the dynamic bearing capacity modulus: Ed; and from the sixth measuring sequence the final

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modulus Edvég, unit: MPa, N/mm2 or MN/m2. The calculation supposes that the loading of the loading disc is transmitted onto a flexible, homogeneous and isotropic half-space. The calculation must be made by the consistent selection of both the Poisson’s ratio characterizing the material and the rigid or elastic Boussinesq-disc multiplier.

The dynamic compactness rate (Trd) can be derived from the six measuring sequences of the depression amplitudes characterizing the deformation. The calculation supposes that the granulous layer made up of an incompressible solid material is three-phase (air + solid part + water) and unsaturated, and it remains so during the compaction carried out during the testing, too.

The calculation reckons with the fact that the optimum compactibility can be reached at an optimal water content; in other case it is going to decrease in line with the moisture correction coefficient (Trw ≤ 1,00), in a calculable way.

The dynamic compactness measurement on-site is based on the determination of the compaction curve evolving during the on-site compaction by answering the Proctor-effort, from which the dynamic compactness rate can be calculated in case that the relative compactness and the actual water content are known. The nature of the compaction curve depends on the efficiency of the preliminary mechanical compaction of the layer; it is somewhere between the uncompressed and fully compressed state. In addition, the relative compactness shows whether any further compaction is possible at a given moisture content; and thus, it is an optimal instrument during the procedural quality control for both manufacturers and technical inspectors.

4. TESTING INSTRUMENTS

4.1. Measuring instrument

It consists of a mechanical manual loading gauge, a loading disc, a measuring block located in the centre thereof and a measuring control and data logger unit (figure 1).

Figure 1 – schematic diagram of a light falling deflectometer

4.1.1. Mechanical loading gauge

The mechanical loading gauge consists of a falling weight and a conductor rod. The gauge serves the production of a dynamic loading (pdin) of > 0.3 MPa, and therefore, it must be shaped in a way that, at the time of the measuring, the falling weight can fall freely when dropped from a height determined during the calibration, and that, through the disc spring, it can ensure a loading power needed for the proper dynamic

Locking button 10 kg falling weight

Depression gauge Logging cable connector

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loading during a given load duration. The centrality of the falling of the falling weight is ensured by the conductor rod. The calibrated dropping height shall be ensured by the positioning of the fixing clamp located on the upper stop above the falling weight. In order to enable the manual lifting of the falling weight it shall be provided with a circular handle exceeding the diameter thereof, and furthermore, it shall be provided with transport protection in order to ensure the fixing during the transportation.

The mass of the falling solid body shall be: m = 11 ±1 kg

The dropping height shall be: h = according to the calibration (72 ±5 cm)

The loading duration must be: t = 18 ±2 ms.

4.1.2. Loading disc

The measuring and centralizing unit shall be placed into the central point of the loading disc. The transmission of the dynamic loading must be made via an in-built centring ball. The loading disc must be equipped with a handle suitable for manual shipment; and in the centralizing block a measuring hollow must be formed.

4.1.3. Determination of the displacement

The depression amplitude of the disc must be determined during the loading time, by a suitable method and with an accuracy of at least 0.01 mm. One of the methods suitable for the determination thereof may be the acceleration gauge built into the measuring hollow of the loading disc. In this case the vertical deformation must be determined through the measuring of the time and the acceleration. The measured data of the displacement must be transmitted to the control – data-logger unit.

4.1.4. Control – data-logger unit

The control – data-logger unit must be formed in a way that it can continuously and automatically register the data of the measurement, it shall possess the necessary sleeve-buttons, the function-switches, display devices and data logger as well as a computer connection for printing and reading out. During the measurement the display of the instrument must show the measurement instructions, the measured data for one sequence, the error signals, the charging level of the voltage supply and other date providing information on the running. The gauge must be equipped with an internal clock and own voltage supply, i.e. a battery needed for the operation.

The operation and operating of the measuring-controlling unit shall be included in an operating manual or service manual issued by the manufacturer (distributor) which must at least contain the following:

• commissioning of the gauge • handling of the control unit, functions, connections • operating modes:

• controlling mode • measuring mode • calibrating mode • printing mode • data transfer mode

• operation and course of modes • storage and maintenance of the gauge • calibration of the instrument and accuracy of the measurement

The control unit shall ensure both the calculation and storage of both the result and graphics from the measured data. One shall enable the on-site printing of the stored test data, or rather the transmission from the data logger to the PC.

4.1.5. Printer

It is a unit serving the on-site printing of the data by which the data can be printed from the control – data-logger unit on site. The content requirements of the printer are as follows:

• identification data • number of the measuring instrument • number of the measurement

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• date.

In case of a dynamic bearing capacity measurement, in addition to the above mentioned: • selected loading level: p, MPa • selected disc model (rigid, elastic disc according to the Boussinesq-model) • path-time graphics at the s11, s12 and s13 measurements • Poisson’s ratio (according to MSZ 2509-3) µ = 0,3–0,4–0,5, if optional • single measured values, numerically • deformations: s11, s12, s13 • maximal speed of the loading disc: v11, v12, v13, mm/s • average values: s1á and v1á, 0.01 mm

• result: á

á

vs

1

1 quotient

• result: Ed dynamic modulus, MPa, N/mm2 or MN/m2.

In case of a dynamic compactness measurement, in addition to the identification and bearing capacity data: • moisture correction coefficient: Trw • single values: s01, s53 • average values: s0á, s1á, s2á, s3á, s4á, s5á • depression amplitudes in the proportion of the number of impacts (compaction curve) • result: relative compactness rate, TrE, % • result: dynamic compactness rate, Trd, %.

On the form, space must be provided for the on-site handnotes, such as for: • the name of project • the identification of the measurement site (km-road section, side, meter) • the examined layer • the name or code of the measuring staff • the weather • other remarks, notes.

4.2. Accessories

The following accessories must be provided at least in order to ensure the measuring mode, to enable higher-mass measurements, or rather to transfer data:

• reserve battery • mains charger and connector • voltage supply connector, 12 V • interface cable for data transmission (if needed) • printing cable (if needed) • printer and paper.

4.3. Sampling instruments

The instruments of the on-site sampling needed for the preparation and shaping of the measurement site and for the determination of the material type and thickness of the examined layer are as follows:

• shovel • spade • plastic bag (for soil sampling) • airtight bowl (for determining the water content) • floating rule (to ensure an even surface) • measuring tape.

4.4. Materials

The materials needed for the test are as follows: • regulating carpet of sand, approx.10 kg • reserve paper roll for the printer.

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4.5. Modes of the measuring instrument

The modes and description of the measuring instrument must be included in an operation manual issued by the manufacturer (distributor). The operation of the following modes must be ensured at least.

4.5.1. Measuring mode

4.5.1.1. Bearing capacity measuring mode

It serves the routine execution of the bearing capacity measurements on site. During the measurement the value of the dynamic modulus rate must be determined by averaging, after a three-drop pre-loading, from a three-drop dynamic loading. At least the following measured values must be displayed on the control - data-logger unit:

• single values: s11, s12, s13 deformations with an accuracy of 0.11 mm

• average value of the depression amplitudes: s1á, mm, with an accuracy of 0.11 mm • dynamic modulus: Ed, MPa, N/mm2 or MN/m2, with an accuracy of 0.1

mm

At the three dynamic loadings specified for the test the measuring instrument shall continuously record the path-time depression curve of the loading disc.

4.5.1.2. Compactness and bearing capacity measuring mode

During the measurement the depression amplitudes must be determined every 18 drops. Since the first six drops are as well needed for the bearing capacity measurement, the first three drops are considered as a kind of pre-loading and the next three drops as dynamic loadings in accordance with par. 4.5.1.1.; and then further 12 impacts are needed for determining the dynamic compactness rate.

The average depression amplitude shall be determined from the measured values per sequence by mathematical averaging, and therefrom the dynamic modulus value, the relative compactness rate and the dynamic compactness rate shall be derived, by indicating at least the following measured values in line with par. 4.5.1.1:

• single values: s01, deformation with an accuracy of 0.01 mm • average values of the depression amplitudes: s0á, s1á, s2á, s3á, s4á, s5á mm, with an accuracy of 0.01

mm • relative compactness rate: TrE, %, with an accuracy of 0.1 • moisture correction coefficient: Trwi, with an accuracy of 0.01 (selected value) • dynamic compactness rate: Trd, %, with an accuracy of 0.1

During the testing the control – data-logger unit shall continuously record the path-time depression curve of the loading disc at the three dynamic loadings s11, s12, s13 .

4.5.2. Calibration mode

A mode applied for own control and calibration. In this mode only one drop depression amplitude is measured (no average value will be calculated). In the calibration mode the display must – accessorily –display both the maximal depression speed of the loading disc (v, mm/s) and the data to be checked and required by the manufacturer, such as the calibration factor and the measuring value directly depending on gravitation.

4.5.3. Printing mode

In printing mode the direct on-site printing of the measurement data must be ensured. In this mode the gauge shall operate in the same way as in the measuring mode.

4.5.4. Data transfer mode

The transfer of the measured data must be enabled from the control-storage to a PC. By selecting the data transfer mode the measurement data shall be transferred to a PC for further storing and processing via the data cable connected to the gauge.

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The detailed operation and description of the control-storage unit formed in accordance with the above-mentioned general principles must be included by the manufacturer (distributor) in an attached service or operation manual, in accordance with the aspects indicated here.

5. TESTS

In case of bearing capacity measurements the staff must attempt to carry out a preliminary test on the material of the testing point (Proctor, grain-size distribution, water content). The measuring staff must learn the manual technique of the measurement, especially the accident-free and safety holding of the circular handle of the recoiling falling weight as well as the fixing of the weight. At low dynamic moduli one must be assume that the falling weight will recoil slightly.

5.1. Preparation of the measurement site

The testing site must be carefully prepared for the measurement. The prepared surface must be even, characteristic for the material layer and of even texture. The loading disc shall be placed on the surface without tilting. The diameter of the prepared surface must exceed the diameter of the disc by at least 10 cm, and it must be almost horizontal. The uneven surface shall be evened by snipping with a floating rule.

If either the earth-work or the material layer to be tested is loose, dried, cracked or uneven, this material must be removed to a necessary degree and the measurement point shall be formed thusly on a ground of the specified size. The execution of the measurement is prohibited on either frozen or inhomogeneous layer.

If the good seating cannot be ensured otherwise, the unevenness of the surface shall be filled up with fine air-dried sand of a quality of H 0/1, in accordance with MSZ 18 293. During the preparation the staff must attempt to provide a regulating sand of a thickness not exceeding the value absolutely necessary for filling up the gaps. It shall fill up only the surface gaps and unevenness and it shall provide a full-surface seating. If the substance thereof considerably differs from the material of the tested structure, the mode of the surface preparation must be indicated in the measurement report.

5.2. Preparation of the gauge for measurement

5.2.1. Preparation of the instrument

The soundness test of the gauge and its preparation for measurement must be executed before the daily measurement tasks, by observing the following aspects:

• the operation of the mechanical loading gauge must be checked (trigger mechanism, conductor, transport protection, cleaning and silicone lubrication),

• the free falling of the falling weight must be controlled, • the immunity of the electronic connectors must be examined, • the immunity of the connecting cables must be checked, • the charging level of the battery of the measuring-controlling unit must be controlled.

Then the own control of the gauge must be carried out, in accordance with par. 5.2.2. If mechanical damage, sticking, line break, contamination or corrosion is being explored during the test the error must be eliminated. If the charging level of the battery is lower than 50 per cent the battery must be either charged up or replaced. Before a major task the batteries must be charged up fully.

5.2.2. Testing measurement (Test)

The prepared gauge shall be put into measurement mode on the testing site, at a typical measurement point. Three pre-loading drops must be followed by three measuring loadings. If the display indicates an error message during the measuring loadings, a measurement error might occur. If the message appears again during the repeated measurement one must clarify whether the problem is caused by the gauge or the tested structure (e.g. a layer of a very low bearing capacity). The possible failure of the device can be certified on site with a soundness test (Enclosure M 1.2). If it is the failure of the device the measurement cannot be started.

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In case that the gauge has no error the deviation of the single values shall be examined. If the deviation thereof does not exceed the specified value, and the graphical drawing of the three drops is close to each other the measurement can be started.

5.2.3. Date setting

The date and time of the test will also appear on the printings on site, thus, the correctness of this datum must be certified before the measurement. It is recommended to check it during the testing measurement stated in par. 5.2.2. If the data on the date and time are not correct they must also be set based either on the service or operation manual of the gauge.

5.3. Dynamic bearing capacity measurement

5.3.1. Measurement in general case

After preparing the measurement site the gauge shall be positioned in accordance with to the following: • the loading disc shall be positioned onto the prepared surface with a sharp move, by not dropping it

down, turning it left and right by 90°, by providin g a seating without tilting • the transmitter of the loading disc shall be connected to the control unit via a measuring cable • the fixed falling weight must be laid onto the centring ball of the loading disc • the transport protection safety pipe of the falling weight shall be trigged • the loading weight must be pulled up and fixed • the measuring-controlling unit shall be switched into measuring mode.

5.3.2. Operations of the dynamic bearing capacity measurement

a) Pre-loading must be done on the measurement by three drops (b–d).

b) The falling weight (if not lifted) must be pulled up to collision and fixed by a locking handle. Look to it that the seating of the centring ball is not raised from the disc and the disc is not displaced. When connecting the falling weight to the trigger mechanism both hands must be used so that we pop up our thumbs to the clamp of the blocking element from above. The falling weight must be directly lifted to the buffer until they mesh. By pulling up the falling weight slowly, the blocking/trigger structure will catch the weight. A too quick, sudden lifting may result in faulty measurement.

c) Along with the vertical positioning of the conductor the falling weight must be trigged. After the recoiling thereof the falling weight shall be put back into the locking gauge by catching the circular handle and pulling it up.

d) As a second sequence, the third pre-loading is followed by three measuring drops (f–j).

e) It is not necessary to store the data of the pre-loadings. If the control gauge has not yet been switched on, then this must be done.

f) The conductor shall be carefully pressed on the loading disc in a vertical position while the falling weight must be trigged. By raising it after the recoiling the falling weight shall be put back. It may be advantageous if the control device gives a sound signal indicating that it is ready for the next drop, too. After the drop one must confirm whether the control unit accepted the measurement or it must be repeated.

The display must show the measured depression amplitude sign: s11

g) After a further drop the falling weight must be caught and fixed. The display must show the latest measured depression amplitude: s12

h) After the last drop the falling weight must be caught and put into a lower position. Now the display must show all three depression amplitudes and the average thereof: s11, s12, s13 and s1á.

If the single depression amplitude values deviate considerably from the average, the measurement must be repeated. If we accept them the dynamic bearing capacity measurement is finished.

i) In this moment, the display shall show the dynamic modulus value along with the number of the measurement, beyond the average value of the depression amplitudes. The sequence number of the measurement serves the marking of the measuring; it shall automatically increase by one unit per measurement.

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j) If needed the measurement data shall be printable. After finishing the measurement the measuring-controlling unit must be switched off; and the falling weight must be secured for transport. By this time the auxiliary and identification data must be recorded; it is reasonable to write it next to the printed results.

k) The gauge shall be carried to the next measurement site with two hands, by the help of the handles positioned in the gravity centre. Be careful that you do not kick the centring rod to anything and avoid its damaging during the shipment.

l) If the display indicates an error message after a drop it must be repeated. In case of a considerable difference in the deflection amplitude the measurement cannot be continued. The error can as well be caused by the dislocation of the centring of either the loading disc or the falling weight . If the error message continuously appears after the repeated drops it might be caused by either the measured material or the failure of the transmitter, the connector or the cable. In order to explore the reason of the device failure it is reasonable to make the soundness test (Enclosure M 1.2).

5.3.3. Measurement under special circumstances on site

It is a special circumstance when the measurement is being made in a working ditch, on the surface of partial backfillings or on a sloping surface. In these cases special attention must be paid to the safety regulations during the measurement (collapsing, traffic). Measurements can be made only at such points where the conditions for safe work are ensured. During the examination on a sloping area the slipping and displacement of the loading disc must be observed. The measurement can be executed only after the creation of an almost horizontal measurement site.

5.4. Dynamic compactness and bearing capacity measu rement

5.4.1 General case of a dynamic compactness and bearing capacity measurement

The preparation of the gauge happens in the same way as stated in par. 5.3.1. The dynamic compactness measurement is done simultaneously with the bearing capacity measurement; therefore, the depression amplitude of the pre-loading drops shall also be measured. After the second sequence needed for the dynamic bearing capacity measurement further four sequences with 3-3 drops are necessary. It means that a total of 18 drops must be made by determining the depression amplitude for each.

5.4.2 Operations of the measurement

The depression amplitude shall be determined by each of the first two sequences (six drops). These six measurement data are necessary for both the dynamic bearing capacity measurement and the dynamic compactness testing. The execution of the measurement occurs in the same way as stated in par. 5.3.2. At the same time, three-three further drops in four sequences shall be carried out after the second sequence, without dislocating the loading disc. By this means, the effort on the layer compacted by a total of 18 drops is approximately as much as the volume of the compaction effort made at the Proctor-test.

The indications and error messages of the display between the measurements are the same as stated in par. 5.3.2 with the difference that in case of a dropping error the drop can never be repeated; a new set-up at a new measurement site is needed.

By continuing the dropping the control-measuring unit shall indicate the depression amplitudes per sequence. Finally, the sequence of measurement available all in all is: sij, where i = 0–5 is the measurement sequence and j = 1–3 means the number of drops. By this, all depression amplitudes arising one by one during the 18 impacts become known. The measurement method requires that, at one measurement point, the ratio of the measured depression amplitudes and the complete deformation, as a characteristic of the material, remains constant.

6. MEASURING RESULTS

6.1. Deflection, depression amplitude

The depression amplitude is the degree of the depression of the disc. Sign: sij, mm

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where i = 0–5, i.e. itincludes six sequences and j = 1–3 drops per sequence. The single values must also be recorded or stored per drop in the control unit. Mathematical average must be formed from the single values per sequence. The sign of the averages is: siá, i.e. the average of every three drops. The accuracy of the depression amplitudes and the average thereof shall be provided with an accuracy of at least 0.1 mm.

6.2. Dynamic bearing capacity modulus

The value of the dynamic modulus (Ed, MPa, N/mm2 or MN/m2) must be calculated with the following formula from the s1á average value worked out from the s11, s12 and s13 depression amplitudes:

á

d srpc

E1

din2 )1( ⋅⋅−⋅

=µ

where:

c – Boussinesq disc multiplier (c = π/2 rigid, c = 2 elastic)

s1á – average vertical displacement of the centre of the disc, 0.01 mm

µ – Poisson’s ratio (according to MSZ 2509-3)

r – radius of the loading disc, mm

AF

p dindin = – volume of the dynamic loading under the disc, MPa, N/mm2 or MN/m2

where:

A – loading disc surface, mm2

KhgmF ⋅⋅⋅⋅= 2din

where:

m – mass of the falling body, kg

g – acceleration due to gravity, m/s2

h – dropping height, m

K – spring constant, N/m.

The final modulus is a special dynamic bearing capacity modulus which characterizes the bearing capacity of the layer completely compacted during the dynamic compactness test, and its value can be calculated with the Ed calculation formula from the s5á average value formed from the s51, s52, s53 depression amplitudes.

The value of the dynamic bearing capacity modulus must be rounded to one decimal. For the full interpretability of the dynamic modulus both the selected c multiplier used in the formula and the applied Poisson’s ratio must be stated or indicated, along with the result.

6.2.1 Equivalent dynamic modulus

An equivalent dynamic modulus worked out with the real c and µ moduli must be constituted from the

measured results, by applying the real µ and the real disc multiplier. (Note: if the c = 2 and µ = 0.4 moduli are set on the gauge, the results thereof can also be converted.) An equivalent dynamic modulus can be worked out only from the measuring results of the same disc size and dynamic loading:

cdpDdE kkEE ⋅⋅= µ,,

where:

µk – conversion multiplier due to Poisson’ ratio if it is not possible to adjust it at the measurement

ck – conversion multiplier of the disc model multiplier if it is not possible to adjust it at the measurement.

Note: if c = 2 and µ = 0.4 moduli are fixed, then:

µk = 0.923, µ = 0.3 in case of a granulous material and

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µk = 1.120, µ = 0.5 in case of a bonded material,

ck = 0.785

If the measurement was carried out with a rigid disc multiplier and a real µ , then EdM,D,p = Ed.

The value of the equivalent dynamic modulus must be rounded to one decimal. For the full interpretability both the diameter of the disc (e.g. 163) and the dynamic loading used must be stated or indicated, along with the result: e.g. pdin = 0,35 MPa

6.2.2. Standard dynamic modulus

In case of measurements resulting in legal effect the mathematical average must be calculated from at least two equivalent dynamic moduli measured within one meter at the same time; and the value of the standard dynamic modulus must be given as a rounded integer. If the deviation thereof from the average exceeds 20 per cent of the average value a third measurement will be necessary. For the full interpretability both the diameter of the disc and the used pdin dynamic loading must be stated or indicated, along with the result.

For example: EdM,D,p = 24 MPa.

6.3. Dynamic compactness rate

The dynamic compactness rate is calculated from the relative compactness and the moisture correction coefficient. The relative compactness must be derived from the curve corrected in accordance with the condition 1, +≥ jiij ss of the depression amplitudes defined in par. 6.1 and measured during the 18 impacts so

that the ∑ ijs deformation and the first depression amplitude ( )01s must be determined. The total

deformation is ∑ ijs where 50 −=i and 31−=j , the total of the single depression amplitudes or rather

( )∑ +++++= ááááááij sssssss 5432103 . Note: Because of the uncertainties of the positioning, the first measured s01 depression amplitude must be checked with the initial linearity of the depression curve presented by a semi-logarithmic diagram; and in justified cases, it must be substituted by the appropriate s01 value. If the ratio of the triple moving average of the drops after the third sequence and the moving average of the measured depression amplitude sequence is > 0.98 then the compaction is very close to the fully compacted stage, and therefore, the other, remaining values can be calculated by the slope of the last measurement points, with linear substitution. At the same time, these measurements must be provided and stored with a separate marking so that they are identifiable.

The relative compactness (TrE) can be calculated from the first depression amplitude and all of the deformations which is:

53

53

01

181

1

100

ss

ss

T ijrE

−

∑−

⋅=

by 18 drops and a compacting effort equivalent to the Proctor effort.

The relative compactness must be rounded to one decimal.

The compactness calculation method worked out from the specific deformation is very sensitive to the measured value of the first depression amplitude (s01).

Another alternative method with a good accuracy in every invertal of the compactness rates includes the calculation of the relative compactness counted from the difference of the depression amplitudes:

mrE DT ⋅−= Φ100,%

where:

Φ – the linear coefficient of the ,%rdmm TV −∆ correlation calculated from the Gd = constant model of the Proctor-test which can be in general and usually taken as 0.365 ± 0.025,

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Dm – deformation indicator: ( )[ ]183∑ +⋅⋅= jiD

mm,D km if i = 0 – 5 and j = 1 – 3 where kD is the difference

of the corrected subsequent depression amplitudes.

Note: Under the Gd = constant model we mean the testing of the Proctor testing specimen consisting of samples of the same dry mass, by different water contents. ∆V is the difference of the lowest volume attached to wopt and the volume of the other samples, the value of which, divided by the area and characterizing the height difference, is ∆Vmm.

The dynamic compactness rate (Trd, %) is the produce of the relative compactness and the moisture correction coefficient:

rprwrErd TTTT =⋅=

In case of a more accurate demand:

The compactness rate produced so is equal with the compactness rate determined by the isotopic measurements (Trp, %).

Calculation of the moisture correction coefficient:

dmaxρρdi

rwT =

The Trw moisture correction coefficient is a density rate determined from the laboratory Proctor soundness test. The value of the ρdmax must be determined from the Proctor soundness test of at least four points, on the material sample, in accordance with MSZ 14 043-7; while the ρdi value must be read off from the Proctor-test curve in the knowledge of the water content (wt) of the material sample of the measurement point according to MSZ 14 043-6 which shall be determined either on site or in a laboratory. In case of either a major work or a material type used on a large surface (e.g. protective coating) the Trw multiplier can be prepared in advance in a table form depending on the water content and it can be applied immediately on site. (Appendix F3)

6.3.1. Standard compactness rate

In case of measurements resulting in legal effect the mathematical average must be calculated from at least two dynamic compactness rates measured within one meter at the same time, and the value of the standard dynamic compactness rate must be given as an integer. Example: TrdM = 95%

If the deviation of the dynamic compactness rate applied in the calculation exceeds 3.0 % from the average a further measurement shall be used in the calculation of the average.

If the value of the Dm deformation index is > 3 during the dynamic compactness measurement and at the same time the measured dynamic modulus is Ed < 10 MPa then the measurement result must be considered as an informative value because the conditions of the on-site compactibility exist only partly. In this case the tested layer can neither be compacted with compacting machines!

7. TEST REPORT

7.1. Content requirements

The test report must include the number of the present specification, the identification data of the testing laboratory, the authorization for measuring and furthermore:

• the type and serial number of the measuring gauge • time of the last calibration • date • measurement site and its identification data • name of the tested structure, earth-work or layer

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• sequence number of the measurement • name of related documents (Proctor densities, water content) • single data of the measurement • average data of the measurement • intermediate result of the test (dynamic modulus, equivalent dynamic modulus) • standard result • accuracy, error or reliability of the test • reference to the uncertainty of the measurement • weather characteristics influencing the result and other conditions • name and signature of the testing person and the date of signing • name and signature of the person in charge for the technical content of the test report and the date of

signing.

In addition it may include: the data esteemed as necessary for the work of the laboratory (project number, code of the testing persons, number of sheets, logo, title, contact, telephone, fax, e-mail).

Note: The test report must imply that the testing results apply only for the tested samples, and that the intermediate data of the test are included in the measurement sheets which are available for the client upon request any time. The test report can be copied only at its full length and by the written consent of the testing laboratory. The test report shall not include any advice, reference to quality or recommendation arising from the testing result.

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ANNEX

M.1. Calibration of the light falling deflectometer

M.1.1 Factory calibration

The device used for the measurement must be calibrated. After the calibration the mechanical loading gauge and the electronic gauge form a coordinated unit.

The data of the calibration (dropping height, mass, date of calibration) must be indicated on the falling weight. The data needed for the control of the gauge (K1, K2 and the tolerance thereof, ∆ calibration factor) and the data of calibration must be included in the calibration report.

At the commissioning of the gauge the specified dropping height set during the calibration and indicated on the data plate must be checked. The calibration on the electronic acceleration gauge shall be indicated on the measuring unit placed on the loading disc, too.

The loading and acceleration (depression measuring) gauge must be revised in a specialized servicing workshop appointed by the manufacturer after every the ten thousand measurements, but at least every two year and it must be calibrated by an authorized calibrating organization. The date and a reference to the suitability must be indicated on the device. In case of either repair or component replacement the gauge must be re-calibrated by an authorized organization.

M.1.2. Soundness test, own control

Switch the assembled gauge into calibration mode as stated in par. 5.3.1. Without dropping the display must show a zero value.

Control value (starting position): K1 = value provided by the manufacturer, with a given tolerance.

After a 180° turn of the loading disc the Control v alue of the display must be K2 = K1 + ∆ in a reversed position which must be set by the manufacturer in the service and operation manual and indicated by the calibrating person in the calibration report, with a ± tolerance. If this is not being fulfilled the gauge is not operable.

Calibration factor: a number determined during the calibration which must be set by the manufacturer in the service and operation manual and indicated by the calibrating person in the calibration report, with a ± tolerance. If the change of these values exceeds the given limit value the device must be re-calibrated; it is not suitable for any measurements.

M.1.2.2. Individual measurement

Because of the completion of either the calibration or the graduation the gauge must also be suitable for individual measurements, i.e. this menu shall not be available from the measuring function. After dropping the weight the data of the individual measuring values must appear.

M.1.2.3. Reliability and accuracy of the measuring method

In order to determine the reliability and accuracy either the provision of the values of the repeatability standard deviation (sr) and the reproductability standard deviation (sR) defined in the related standard or the calculation of the examination reliability determined by statistical methods at a high sampling number is necessary. After all calibrations the accuracy of the measurement must be re-calculated .

M.1.2.4. The light falling deflectometer suits for the measurement specified in the specification if the depression amplitudes’:

• repeatability standard deviation is sr ≤ 0.8 • reproductability standard deviation is sR ≤ 1.2 • the calculated measurement error: in case of an accuracy of 0.01 mm at the depression amplitude

measurement and of an accuracy of 5 % at the dynamic loading power measuring, the measurement error is 5.2 % of the measured Ed dynamic modulus.

In case of an accuracy of 0.01 mm at the depression amplitude measurement and an accuracy of 5% at the dynamic loading power measuring, the measurement error includes the measured dynamic compactness degree Trd ±2,0%. The error of the dynamic compactness rate shall be calculated from the large sample

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weighted with the maximal ±0,15 g/cm3 measurement error of the parameters specified during the Proctor-test, and in case of a higher density fluctuation from the accuracy large sample.

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APPENDIX

F.1. Terms used in the calculations

The dynamic bearing capacity modulus must be calculated from the formula stated in par. 6.2.

Deformation measurement applying acceleration measuring

2

2t

as ⋅=

where:

a – measured acceleration

t – measured time

The relative compactness rET( , %), the moisture correction coefficient ),( rwT and the dynamic compactness

rate %),( rdT must be calculated from the formula stated in par. 6.3.

F.2. Technical requirements

Design requirements of the mechanical loading gauge are: - volume of the falling weight (including handles): 11 ±1 kg - total volume of the conductor (including the spring elements consisting of

disc springs) including the transport protection of the falling weight, the trigger mechanism and the tilt protection

maximum 5 ±0,5 kg - dynamic loading at least: 0,3 MPa - loading duration: 18 ±2 ms

Design requirements of the loading disc are: • diameter of the loading disc: 163 mm • thickness of the loading disc: at least 20 mm • total volume of the loading disc 15 ±1,5 kg

(including a measuring tunnel for the installation of the sensor and the carrying handles)

Fixed technical data on the acceleration measurement used for the deformation measurement: • measuring interval of the installed acceleration recorder: 0–50 g

In case that other deformation measuring device and acceleration measuring gauge are applied: • measuring duration: 18 ±2 ms • processed measurement signal: at least 25 signals/18 ms • reading accuracy of the deformation: at least 0.01 mm • accuracy of the quartz clock: maximum ±1,5 s per day • reading accuracy of the deformation: at least 0.01 mm

F.3. Calculation and application of the moisture co rrection coefficient

The first result of the on-site dynamic compactness measurement is the relative compactness (TrE, %) which shows what the compactness of the layer is like in comparison with the highest possible compactness reachable at the actual water content. The moisture correction coefficient is not needed for the relative compactness measurement. It is a new testing parameter which is in the evaluation of the efficiency of the compacting instruments important. If it is known, the decision can be made whether further compaction can be executed on the layer, by the given moisture content.

For the calculation of the dynamic compactness rate the measured relative compactness must be corrected, depending on to what extent the water content on site deviated from the optimal value. That rate is called the moisture correction coefficient which is being determined by the Proctor-test and which is the quotient of the dry density attached to the actual water content and the highest dry bulk density attached to the optimal water content:

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dmaxρρdi

rwiT =

,1<rwT except wopt, where 00.1=rwT

Accordingly, the Proctor-test is also needed for the dynamic compactness examination, i.e. for the calculation of the irwi wT − moisture correction curve or table. The Trwi must be determined for a given material, at least for around wopt ±5 % per 1 %, both upwards and downwards from the optimal water content (by reading off the relating densities from the Proctor-test curve, is being divided by ρdmax density).

The Trwi values calculated thusly per material type are sufficient for applying them in the compactness measurement on site, by measuring the actual water content. During the dynamic compactness measurement sample must always be taken for the determination of the water content in the laboratory. It is advantageous if the natural water content (wt) can be determined with the appropriate instrument on site.

Sand of Dunaharaszti

Dry branch Moist branch

–5% –4% –3% –2% –1% wopt

+1% +2% +3% +4% +5%

0.956 0.973 0.989 0.995 1.000 1.000 0.997 0.989 0.962 0.940 0.892

The Trw moisture correction table must be determined by the soundness test stated in MSZ 14 043-7 for five different water contents and at least two, but possibly three parallel samples, with ∆w water content stages evenly distributed up to the saturation line S = 0.9. The determination of the Proctor-curve shall occur from the measured 10-15 Proctor-points with a second-degree approximate curve, possibly by controlling the tightness of the regression, and not by the simple connection of the points. The ρdi values must be determined from the formula of the curve derived thusly, by ∆w = 1% stages; and the value of the moisture correction coefficient must be given in a table form in comparison to the ρdmax.

Note: The mathematical determination of the second-degree parameters of the Proctor-curve can be improved by referring subsidiary points of a smaller density rate than the measured densities, being drawn on the saturation line S = 0.9 that are.

The Trw values at the measured relative compactness of TrE = 100% mean exactly a dynamic compactness rate/100, i.e. inthe present example a compactness rate of a maximum of 89.2% (Trd) can be reached by a compaction of a maximum of TrE = 100 % at wopt + 5% on-site water content.

If, for example, the measured relative compactness was not %100=rET but rather %2.96=rET at a

%5opt −w water content on-site, then the dynamic compactness rate would be 0.92956.0%, xTrd = .

The machine compaction above the optimal water content is much more difficult in the moist branch which is well demonstrated by the rwT values and can be calculated in advance. In the moist branch the insufficient air content needed for the compaction may cause another problem, which can be anticipated from the air content/optimal air content ratio, and furthermore, the saturation, which can be calculated from the soundness test if ρs is known.

From the specified limit value of the compactness rate the relative compactness rate to be reached during the construction may also be calculated. In this case it is enough if we attempt to reach this by machine compaction. If, for example, we measure a %3opt −w on-site water content and the qualification requirement

includes a compactness rate like %0.95≥= rdrp TT , then, in order to fulfil this, the

%1.96989,0

0,95 =≥= rErw

rd TT

T relation must be calculated from the example mentioned above. If we can

provide for this during the construction then the qualifying compactness measurements will be acceptable!

The expected efficiency of the compacting effort can also be estimated if the rwT moisture correction

coefficient is known. If, by applying the above example, the on-site water content ( )tw is s %4opt +w then

%100=rET , i.e. even by a machine compaction to the maximal relative compactness we can only reach a

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rdT==⋅ %0.94940.0100 maximum compactness rate, in other words, the 95 % cannot be reached any

way! In this case either a new material type shall be selected or the water content must be decreased.

The application of the dynamic compactness measurement method and the moisture correction coefficient demonstrated above may support the proper selection of the compacting method during the construction, as well as the applicability of the material yet by the time of the pre-testing in the laboratory, and therefore, it can be an effective instrument for quality management. Thereunto, only the water content of the local material (transported material) needs to be known beyond the laboratory Proctor-test – which will be made anyhow -; and therefrom the curve of the moisture correction coefficient can be calculated simply and in advance. The dynamic compactness rate ( ),%rdT is equivalent to the compactness rate determined by the

isotopic measurement, and thus, one must consider the related conventional qualification requirements as a limit value.

Finally, the measuring method and its theory help the forming and spreading of a new contractor attitude, inasmuch as it emphasizes both the importance of the moisture content of the applied granulous materials and the compactibility that can be reached by some rolling effort and checked easily. The applicability of the gauge is largely supported by its small size and easy operation. Owing to its environmental and health impacts one must stress that this method can be used without any isotopic source, in an environment-friendly way.

F.4. Demonstration of the calculations

Beside the recommended PC processing we provide a calculation sample on the dynamic compactness and bearing capacity measurement. Downloaded data resulting from the measurement (see figure 2):

• serial number of the device (Device Nr) • number of the measurement (Measure Nr) • time of the measurement • identification code of the measuring staff (ID) • type of the measurement (BC) • Boussinesq disc multiplier (Model) • applied Poisson’s ratio ( )µ

• typed-in value of the Trw moisture correction coefficient used on site • dynamic loading power, N • radius of the disc, cm • s01–s53 depression amplitudes resulting from the measurement (in a dimension of 100 mm) • v01–v536 disc-depression speed resulting from the measurement

Figure 2 – Data stored in the measuring control unit, downloaded onto the PC

STX Device Nr = 4080408 Measure Nr = 140 2005. 01. 19 13:56:24 User ID = 1 Type = BC Model = 1,571 Poisson = 0,3 Trw = 0,998 Fdin = 7200 Radius = 81,5 s01= 257 V01= 409 s02= 75 V02= 181 s03= 68 V03= 157 s11= 54 V11= 152 s12= 47 V12= 135 s13= 40 V13= 124 s21= 38 V21= 129 s22= 38 V22= 124 s23= 35 V23= 118 s31= 33 V31= 116 s32= 31 V32= 124 s33= 38 V33= 126 s41= 32 V41= 124

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s42= 32 V42= 106 s43= 35 V43= 113 s51= 34 V51= 115 s52= 31 V52= 123 s53= 29 V53= 119 ETX

Calculation of dynamic moduli

According to the data in Figure 2: µ = 0.3 (Poisson) and 2/π=c (Model), r = 81.5 mm (Radius)

Therefrom:

,1á

d sC

Eµ⋅= where 2.40=⋅ µC and

( )3

40.047.054.01

++=á

s , i.e. 5.8547.0

2.40 ==dE MPa

In the same way:

MPa7.12931.0

2.40

5vég ==⋅=

ád s

CE

µ, where 31.0

3

29.031.034.05 =

++=ás mm

Calculation of the moisture correction coefficient (Trw)

With the calibrated Trident T-90 instrument the measured water content on site is: wt = 4.0%

Calculated from the Proctor-curve 980.090.1

862.1

max

==d

d

ρρ

, where dρ means a w = 4,0% volume density.

If we prepared the Trw-curve (table) previously then we only need to read off the Trw = 0.980 value attached to %0.4=w .

Calculation of the relative compactness rate

The stored data are the hundredfold of the depression amplitudes. After the calculation of the dynamic modulus we correct the depression amplitudes to the calculation of the dynamic compactness rate and we put it into the form 1−≥ ijij ss (in this case it is a constant till S32, and then its value is 31 up to 5233 ss − ).

Thereafter the depression differences will be formed by the 1+− ijij ss formula:

From Figure 2 the ordered data line will be: 182, 7, 14, 7, 7, 2, 0, 3, 2, 2, 0, 0, 0, 0, 0, 0, 2.

Since the value of the Φ linear coefficient calculated from the Proctor-test’s Gd = constant model equals to the general condition 0.365 ±0,25 we are going to use it. In order to simplify the calculation and because of the back-calculation of the mm data, practically, the mrE DT ⋅−= 365.0100 rate shall be calculated with the

1000

65.3100

10010

365.010100,% mm

rE

DDT

⋅−=

⋅⋅⋅−

= formula .

Dm – (deformation index)

Its value is the total of the data weighted by the drops and of a number answering the drops, in other words:

Dm= [1⋅(182)+2⋅(182+7)+3⋅(182+7+14)+4⋅(182+7+14+7)+5⋅(182+7+14+7+7)+6⋅(182+7+14+7+7+2)….. +18⋅ (182+7+14+7+7+2+03+2+2+0+0+0+0+0+0+2)]/18 000= 1.90 mm

Therefrom, the relative compactness is %1.9390.165.3100100 =⋅−=⋅Φ−= mrE DT

The calculated dynamic compactness rate is: %2.91%1.93980.0%, =⋅=⋅= rErwrd TTT

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Referred Hungarian national standards and road spec ifications

MSZ 2509-3 Testing of the bearing capacity of road structures. Disc examination

MSZ 14 043-6 Soil-mechanical tests. Volume and mass rates of phases forming the soil

MSZ 14 043-7 Soil-mechanical tests. Examination of the compactibility and compactness of soils

MSZ 18 293 Sand, sandy gravel and gravel

ÚT 2-2.117 Dynamic bearing capacity measurement

ÚT 2-2.119 Bearing capacity measurement with light falling deflectometer

ÚT 2-3.103 Radiometric compactness measurement. Determination of the volume density and water content of earth-works, base layers without binding material and road beds with hydraulic binding agent

ROAD TECHNICAL SPECIFICATION ÚT 2-2

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