Title of Invention	"A PAVEMENT TESTING SYSTEM".
Abstract	A pavement testing machine characterized in that a servo-hydraulic system (1) to generate vibration of the frequency of 1 to 100 htz., power pack (4) and vibrating mass (6) being mounted on a trolley (2) such that said mass being raised and lowered by hydraulic jacks/lift during the testing process by the machine, control system being provided to control various operations of the machine, a central processing unit (25) being provided for collecting data and analyzing the same to provide the required results regarding the strength of the different layers of the pavement.

Title of Invention

"A PAVEMENT TESTING SYSTEM".

Abstract

A pavement testing machine characterized in that a servo-hydraulic system (1) to generate vibration of the frequency of 1 to 100 htz., power pack (4) and vibrating mass (6) being mounted on a trolley (2) such that said mass being raised and lowered by hydraulic jacks/lift during the testing process by the machine, control system being provided to control various operations of the machine, a central processing unit (25) being provided for collecting data and analyzing the same to provide the required results regarding the strength of the different layers of the pavement.

Full Text	This invention relates to a pavement testing system Particularly, this invention relates to air-field pavements and express ways testing machine. Airport pavements carry aircraft of the order of 400 tonnes, which is likely to increase further in future. Very thick formations have to be provided for these aircraft to operate. These pavements under go damage over a period of time due to fatigue or weather related effects. If the pavement is weaker than the requirement of aircraft load, it results in bumpy ride, cracks, potholes and surface disintegration. The pavements have, therefore to be tested, evaluated and rehabilitated. Since these failures may occur because of infirmities in the layers below the surface, it is necessary to know their condition as well. Airport pavements are busy areas. It is very difficult to take out time for long tests and subsequent repairs. Conventional test, which requires loading the pavement by large number of sand bag (of the order of 100 tonnes) through a loading frame and plates to the breaking point. This test is expensive, takes a very long time and, therefore, impracticable in the present context. Equipment have, therefore, been developed to generate loads dynamically. One such method is to drops the load freely from a height and measures resulting deflections. These loads and deflections are used for calculating the strength of pavement. However, falling weight deflectometer does not give the correct information about the layers of pavement as it ignores the multi-layer dynamic force, which have their natural frequency and damping characteristics. Therefore, the main object of this invention is to propose a novel payment testing machine, which obviates a disadvantages associated with the prior art. Another object of the invention is to provide a novel pavement testing machine, which makes the test fast, economical and provides meaningful information on the pavement layer system and its load carrying capabilities. According to this invention there is provided a pavement testing system characterized in that a servo-hydraulic system to generate vibration of the frequency of 1 to 100 htz., power pack and vibrating mass being mounted on a trolley such that said mass being raised and lowered by hydraulic jacks/lift during the testing process by the machine, control system being provided to control various operations of the machine, a central processing unit being provided for collecting data and analyzing the same to provide the required results regarding the strength of the, different layers of the pavement. In accordance with this invention the pavement testing machine has a servo-hydraulic system to generate the vibrations at a load level upto +9 kips over a static weight of 10 kips at a frequency varying from 1 to 100 hts. The power pack vibrating mass are mounted on a trolley (not shown) such that the mass and the test system are lowered or raised by hydraulic jacks while conducting the test. A control system is provided with said machine for controlling different operations of the machine. A central processing unit (CPU) having special kind of computer program is provided such that to receive the data regarding the vibrations caused by the machine and analyzing the same in order to provide the required information regarding the strength of the pavement at the side itself. Thus it is seen that the pavement testing machine of the present invention provides the required information regarding the pavements instantaneously and without damaging the pavement. The pavement testing machine according to a preferred embodiment is herein described and illustrated in the accompanying drawing wherein: Fig. 1 shows the perspective side view of the pavement testing machine and Fig.2 shows the schematic of the pavement testing machine. Referring to the drawings particularly fig.l the pavement testing machine has servo hydraulic valves 1 mounted on the chassis of a trolley 2 for generating the vibration at a load level upto +9 kips over a static weight of 10 kips at a frequency between 1-100 htz. A hydraulic power pack 4 having the power system 5 is provided towards the front end of the trolley 2 for lowering and raising the mass 6 by means of hydraulic jacks during the testing operation of the machine. A system lift 7 is provided in the middle of the trolley 2. Directional valves 8 are provided on the back portion of the trolley 2 for changing the direction of the hydraulic oil for controlling the operation of the machine. A central processing unit (not shown) is provided for receiving the signals from the different parts of the machine and processing the same in order to provide the test report of the pavement at the side itself. Reference is now made to fig.2 the mass 6 is mounted on an actuator 9 having a pulse generator 10 at the near bottom end thereof. Load cells 11 are provided for supporting the actuator 9 over the acceleration transducers 12. A hydraulic distribution system 13 is provided for providing oil supply to the actuator and pulse generator as and when required by the operation of the solenoid control valve 14. A frequency programmer 15 is connected to a solenoid valve 14 so as to operate the solenoid valve 14. A power supply 16 is provided to provide power to the hydraulic distribution system 13 through a hydraulic power supply means 17. The hydraulic distribution system 13 is also connected to a servo amplifier 18 through a drive valve 19. The servo amplifier is connected to an amplitude comparator 20 which is connected to a comparator 21 connected to the load cells 11. The comparator is also connected to a CPU 25 through a signal conditioner 26. A signal conditioner 22 is connected to the frequency programmer 15 through an indicator 23 and displacement signals 24. A led display 27 and a recorder 28 are provided with CPU 25. A processor 29 is connected with the CPU 25 for providing a stiffness of pavement. The function of the machine is to impose controlled dynamic loading on the surface of the pavement and to measure the dynamic response of that surface to the applied loading. The dynamic loading is developed by acceleration of a mass alternatively up and down about the midpoint. This is done by extending and retracting a hydraulic actuator, which is attached between the mass and the base of the structure on ground. When the actuator is extended and retracted sinusoidally, the resultatn acceleration forces add to or subtract from the applied static load in proportion to the frequency and amplitude of the mass motion. The mass weighs about 4 tons and the static load of the system is 8 tons. The actual loads applied to the loading plate are measured by three force transducers positioned between the base of the actuator and the ground contact plate. The output signals from the transducers are conditioned and displayed for control on the instrument panel. A velocity transducer attached to the loading plate produces an electric signal proportional to the velocity of the laoding plate in response to the applied forcing function. This signal is integrated, conditioned and displayed on the control panel to indicate the dynamic displacement of the test surface in response to applied dynamic forces. The hydraulic system provides power to operate the lift and mass actuator through series of mass. The fluid flow is provided by a pump, which is driven by the engine of the machine. The flow from the pump is directed through relief valve and into a 4-way 3-position valve known as stage valve. When no bolt is applied to this valve the system pressure is near zero and in standby mode. When 12 volts DC is applied across the coil of solenoid valve the fluid flow is directed from the pressure port to the other pressure ports and to the port of a second 4-way, 3- position valve called as elevator valve. When no volt is applied to the elevator valve the flow is directed out of the above ports and to the top chamber of the lift cylinder causing the piston rod to extend and thus lowering the force generator to the test surface of the pavement. When 12 volts DC is applied to the 2nd solenoid valve the flow is directed out of the other port to the lower chamber of the lift cylinder causing the cylinder to retract and thus raising the force generator. A check valve between the elevator and the lift cylinder is provided to lock the lift cylinder in the up or down position until powered to another position. A pressure relief valve between the first port and the lock valve controls the down loading pressure in the lift cylinders. A 4-way servo valve directs flow out of 1st and 2nd port in direct proportion to the applied current. The sevo valve ports are connected to the vibrate cylinder up and down ports. The velocity and direction of the motion of the vibrate cylinder which drives the mass is controlled by the current applied to the motor of the servo valve. A filter is provided to clean hydraulic oil. A cooler is provided to cool the hydraulic oil and a pressure gage is provided to measure the pressure of the flow of the oil. WE CLAIM 1. A pavement testing machine characterized in that a servo-hydraulic system (1) to generate vibration of the frequency of 1 to 100 htz., power pack (4) and vibrating mass (6) being mounted on a trolley (2) such that said mass being raised and lowered by hydraulic jacks/lift during the testing process by the machine, control system being provided to control various operations of the machine, a central processing unit (25) being provided for collecting data and analyzing the same to provide the required results regarding the strength of the different layers of the pavement. 1. A pavement testing machine as claimed in clam 1 wherein said servo hydraulic means comprises a hydraulic distribution system (13) being connected to the actuator (9) provided for raising and lowering said mass, said hydraulic distribution system being connected to a frequency programmer (15) through a solenoid control valve (14) said frequency programmer connected to a CPU (25) so as to send and receive the signals from the CPU and to operate said solenoid control valve. 3. A pavement testing machine as claimed in claims 1 and 2 wherein said a pulse generator (10) supported by load cells (11) being provided to provide vibrations to said actuator, acceleration transducers (12) being provided to increase and reduce the vibrations by said pulse generator. 4. A pavement testing machine as claimed in claim 1 wherein said pulse generator being connected to said CPU through a signal connected to a integrator being connected to a displacement signal. 5. A pavement testing machine as claimed in claim 2 wherein said servo hydraulic distribution system being connected to a comparator (20) through a drive valve servo amplifier (19) and amplitude compensator (20) being connected with each other. 6. A pavement testing machine as claimed in claim 5 wherein said comparator is connected to said CPU through a signal conditioner (26). 7. A pavement testing machine as claimed in claim 1 wherein said mass is supported of a plurality of guides being provided to guide up and down movement thereof. 8. A pavement testing machine substantially as herein described and illustrated with reference to the accompanying drawings.

Full Text

This invention relates to a pavement testing system Particularly, this invention relates to air-field pavements and express ways testing machine.
Airport pavements carry aircraft of the order of 400 tonnes, which is likely to increase further in future. Very thick formations have to be provided for these aircraft to operate. These pavements under go damage over a period of time due to fatigue or weather related effects. If the pavement is weaker than the requirement of aircraft load, it results in bumpy ride, cracks, potholes and surface disintegration. The pavements have, therefore to be tested, evaluated and rehabilitated. Since these failures may occur because of infirmities in the layers below the surface, it is necessary to know their condition as well.
Airport pavements are busy areas. It is very difficult to take out time for long tests and subsequent repairs. Conventional test, which requires loading the pavement by large number of sand bag (of the order of 100 tonnes) through a loading frame and plates to the breaking point. This test is expensive, takes a very long time and, therefore, impracticable in the present context.
Equipment have, therefore, been developed to generate loads dynamically. One such method is to drops the load freely from a height and measures resulting deflections. These loads and deflections are used for calculating the strength of pavement. However, falling weight deflectometer does not give the correct information about the layers of pavement as it ignores the multi-layer dynamic force, which have their natural frequency and damping characteristics.

Therefore, the main object of this invention is to propose a novel payment testing machine, which obviates a disadvantages associated with the prior art.
Another object of the invention is to provide a novel pavement testing machine, which makes the test fast, economical and provides meaningful information on the pavement layer system and its load carrying capabilities.
According to this invention there is provided a pavement testing system characterized in that
a servo-hydraulic system to generate vibration of the frequency of 1 to 100 htz., power pack and vibrating mass being mounted on a trolley such that said mass being raised and lowered by hydraulic jacks/lift during the testing process by the machine, control system being provided to control various operations of the machine, a central processing unit being provided for collecting data and analyzing the same to provide the required results regarding the strength of the, different layers of the pavement.
In accordance with this invention the pavement testing machine has a servo-hydraulic system to generate the vibrations at a load level upto +9 kips over a static weight of 10 kips at a frequency varying from 1 to 100 hts. The power pack vibrating mass are mounted on a trolley (not shown) such that the mass and the test system are lowered or raised by hydraulic jacks while conducting the test. A control system is provided with
said machine for controlling different operations of the machine. A central processing unit (CPU) having special kind of computer program is provided such that to receive the data regarding the vibrations caused by the machine and analyzing the same in order to provide the required information regarding the strength of the pavement at the side itself.
Thus it is seen that the pavement testing machine of the present invention provides the required information regarding the pavements instantaneously and without damaging the pavement.
The pavement testing machine according to a preferred embodiment is herein described
and illustrated in the accompanying drawing wherein:
Fig. 1 shows the perspective side view of the pavement testing machine and
Fig.2 shows the schematic of the pavement testing machine.
Referring to the drawings particularly fig.l the pavement testing machine has servo hydraulic valves 1 mounted on the chassis of a trolley 2 for generating the vibration at a load level upto +9 kips over a static weight of 10 kips at a frequency between 1-100 htz. A hydraulic power pack 4 having the power system 5 is provided towards the front end of the trolley 2 for lowering and raising the mass 6 by means of hydraulic jacks during the testing operation of the machine. A system lift 7 is provided in the middle of
the trolley 2. Directional valves 8 are provided on the back portion of the trolley 2 for changing the direction of the hydraulic oil for controlling the operation of the machine. A central processing unit (not shown) is provided for receiving the signals from the different parts of the machine and processing the same in order to provide the test report of the pavement at the side itself.
Reference is now made to fig.2 the mass 6 is mounted on an actuator 9 having a pulse generator 10 at the near bottom end thereof. Load cells 11 are provided for supporting the actuator 9 over the acceleration transducers 12. A hydraulic distribution system 13 is provided for providing oil supply to the actuator and pulse generator as and when required by the operation of the solenoid control valve 14. A frequency programmer 15 is connected to a solenoid valve 14 so as to operate the solenoid valve 14. A power supply 16 is provided to provide power to the hydraulic distribution system 13 through a hydraulic power supply means 17. The hydraulic distribution system 13 is also connected to a servo amplifier 18 through a drive valve 19. The servo amplifier is connected to an amplitude comparator 20 which is connected to a comparator 21 connected to the load cells 11. The comparator is also connected to a CPU 25 through a signal conditioner 26. A signal conditioner 22 is connected to the frequency programmer 15 through an indicator 23 and displacement signals 24. A led display 27 and a recorder 28 are provided with CPU 25. A processor 29 is connected with the CPU 25 for providing a stiffness of pavement.
The function of the machine is to impose controlled dynamic loading on the surface of the pavement and to measure the dynamic response of that surface to the applied loading. The dynamic loading is developed by acceleration of a mass alternatively up and down about the midpoint. This is done by extending and retracting a hydraulic actuator, which is attached between the mass and the base of the structure on ground. When the actuator is extended and retracted sinusoidally, the resultatn acceleration forces add to or subtract from the applied static load in proportion to the frequency and amplitude of the mass motion. The mass weighs about 4 tons and the static load of the system is 8 tons. The actual loads applied to the loading plate are measured by three force transducers positioned between the base of the actuator and the ground contact plate. The output signals from the transducers are conditioned and displayed for control on the instrument panel. A velocity transducer attached to the loading plate produces an electric signal proportional to the velocity of the laoding plate in response to the applied forcing function. This signal is integrated, conditioned and displayed on the control panel to indicate the dynamic displacement of the test surface in response to applied dynamic forces. The hydraulic system provides power to operate the lift and mass actuator through series of mass. The fluid flow is provided by a pump, which is driven by the engine of the machine. The flow from the pump is directed through relief valve and into a 4-way 3-position valve known as stage valve. When no bolt is applied to this valve the system pressure is near zero and in standby mode. When 12 volts DC
is applied across the coil of solenoid valve the fluid flow is directed from the pressure port to the other pressure ports and to the port of a second 4-way, 3- position valve called as elevator valve. When no volt is applied to the elevator valve the flow is directed out of the above ports and to the top chamber of the lift cylinder causing the piston rod to extend and thus lowering the force generator to the test surface of the pavement. When 12 volts DC is applied to the 2nd solenoid valve the flow is directed out of the other port to the lower chamber of the lift cylinder causing the cylinder to retract and thus raising the force generator. A check valve between the elevator and the lift cylinder is provided to lock the lift cylinder in the up or down position until powered to another position. A pressure relief valve between the first port and the lock valve controls the down loading pressure in the lift cylinders. A 4-way servo valve directs flow out of 1st and 2nd port in direct proportion to the applied current. The sevo valve ports are connected to the vibrate cylinder up and down ports. The velocity and direction of the motion of the vibrate cylinder which drives the mass is controlled by the current applied to the motor of the servo valve. A filter is provided to clean hydraulic oil. A cooler is provided to cool the hydraulic oil and a pressure gage is provided to measure the pressure of the flow of the oil.

WE CLAIM
1. A pavement testing machine characterized in that a servo-hydraulic system (1) to generate vibration of the frequency of 1 to 100 htz., power pack (4) and vibrating mass (6) being mounted on a trolley (2) such that said mass being raised and lowered by hydraulic jacks/lift during the testing process by the machine, control system being provided to control various operations of the machine, a central processing unit (25) being provided for collecting data and analyzing the same to provide the required results regarding the strength of the different layers of the pavement.
1. A pavement testing machine as claimed in clam 1 wherein said servo hydraulic means comprises a hydraulic distribution system (13) being connected to the actuator (9) provided for raising and lowering said mass, said hydraulic distribution system being connected to a frequency programmer (15) through a solenoid control valve (14) said frequency programmer connected to a CPU (25) so as to send and receive the signals from the CPU and to operate said solenoid control valve.
3. A pavement testing machine as claimed in claims 1 and 2 wherein said a pulse generator (10) supported by load cells (11) being provided to provide vibrations to said actuator, acceleration transducers (12) being provided to increase and reduce the vibrations by said pulse generator.
4. A pavement testing machine as claimed in claim 1 wherein said pulse generator being
connected to said CPU through a signal connected to a integrator being connected to a
displacement signal.
5. A pavement testing machine as claimed in claim 2 wherein said servo hydraulic
distribution system being connected to a comparator (20) through a drive valve servo
amplifier (19) and amplitude compensator (20) being connected with each other.
6. A pavement testing machine as claimed in claim 5 wherein said comparator is
connected to said CPU through a signal conditioner (26).
7. A pavement testing machine as claimed in claim 1 wherein said mass is supported of a
plurality of guides being provided to guide up and down movement thereof.
8. A pavement testing machine substantially as herein described and illustrated with
reference to the accompanying drawings.

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Patent Number

230883

Indian Patent Application Number

639/DEL/2001

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

28-Feb-2009

Date of Filing

06-Jun-2001

Name of Patentee

INTERCONTINENTAL CONSULTANTS AND TECHNOCRATS PVT. LTD.

Applicant Address

A-11, GREEN PARK, NEW DELHI.

Inventors:

#	Inventor's Name	Inventor's Address
1	KIRAN KUMAR KAPILA	A-11, GREEN PARK, NEW DELHI.
2	HARENDRA KUMAR KULSHRESHTHA	A-11, GREEN PARK, NEW DELHI.

PCT International Classification Number

G01N 19/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA