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Description
High capacity equipment for the continuous measurement of the Sideway-force
Coefficient between tyre and road surface.
The SCRIM consists of a truck with a water tank and a blank test tyre
mounted on its right side so that the measures are taken on the part of the road
most influenced by traffic loads. A water jet is sprayed in front of the wheel,
dispensing a water film of constant thickness.
The wheel is placed on the road surface forming a permanent angle with the
longitudinal axle of the truck. The sideway force tyre-pavement is measured by
means of a transductor placed into the measurement wheel axle.
Inside the driver's cab there is a data adquisition system, a monitor that
displays the speed and side friction data, and a keyboard that allows to insert
extra data.
The Road Research Centre counts with two equipments for the evaluation of
skid resistance, which technical characteristics are mentioned below, being the
main differences between them that the modern one has a laser texturometer and a
GPS equipment.
Technical characteristics
Equipment (ERT) for evaluation of skid resistance of pavements
- Test wheel of 76x508 mm, tyre pressure 350 kPa and resilience and hardness
standardised. Test wheel applied load: 200 kp.
- Angle of deviation of wheel: 20º.
- Water tank capacity: 8.000 l.
- Approximate capacity: 250 km/day.
SCRIM equipment
- Test wheel of 76x508 mm, tyre pressure 350 kPa and resilience and hardness
standardised. Test wheel applied load: 200 kp.
- Angle of deviation of wheel: 20º.
- Water tank capacity: 10.000 l.
- 32 Khz LáserTexturometer.
- Positioning system by means of a G.P.S.
- Approximate capacity: 260 km/day.
Applications
- Measurement and recording of sideway force coefficient for all kind of
pavements.
- Systematic surveying of road networks.
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Description
The FWD is an equipment that generates a load pulse by dropping a weight on
a damped spring system mounted on a footplate. The weight, the spring system and
drop height can be adjusted to achieve the desired impact loading on the
pavement. The Road Research Center counts with two of these types of equipment,
which technical differences are mentioned below.
Technical characteristics
65 kN Falling Weight Deflectometer
- The load pulse is similar to the one produced by a vehicle running at 70
km/h. The loadtime is 30 milliseconds and the equivalent peak load is 65 kN.
- The deflection produced by the load is measured with 5 sismometers
positioned, one at the center of the plate, and the others at 20, 30, 45 and 90
cm distance.
- The capacity of the equipment is about 2 km/h (considering a distance
between testing points of 25 m).
150 kN Falling Weight Deflectometer
- The load pulse is similar to the one produced by a vehicle running at 70
km/h. The loadtime is 40 or 60 milliseconds and the equivalent peak load is 150
kN.
- The deflection produced by the load is measured with 7 sismometers
positioned, one at the center of the plate, and the others at 30, 45, 60, 90,
120 and 150 cm distance.
- It has a sensor to measure the pavement surface temperature.
- The capacity of the equipment is about 2 km/h (considering a distance
between testing points of 25 m).
Applications
- Evaluation of the structural capacity of flexible, semi-rigid and rigid
pavements.
- Evaluation of the load transfer in joints of concrete pavements.
- Field control of subgrades and aggregate layers of pavement.
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Description
High capacity equipment for the measurement of pavement deflections.
Technical characteristics
- Testing speed about 3-4 km/h.
- The data are obtained in two measurement lines.
- Distance between testing points is 5 meters.
- At each test point about 60 measurements of deflection are taken (allowing
to obtain the influence line of the deflection), and the whole length of measure
is 1,5 m.
- The data acquisition and management are computerized.
Applications
- Measurement and recording of pavement deflections under a truck axle load,
almost continuously.
- Obtention of the influence line of the deflection at each test point.
Description
The Profilograph is a piece of equipment that registers longitudinal and
transversal profiles and texture of roads. It works on a Transporter Kombi
Volkswagen vehicle.
The front part consists of a beam with 15 laser cameras that measure road
surface evenness. There is also another laser camera to measure texture. The
ends of the measure beam are retractable so that the width of the beam does not
exceed the vehicle during transportation.
Inside the vehicle there is an electric power supply and the data
acquisition systems. The operator has a control panel, a keyboard and a LCD
screen.
Due to the high measuring speed (25-120 km/h, depending on the distance
between sections), the test can be carried out without disturbing the normal
traffic flow.
Technical characteristics
- 15 laser cameras of 16 kHz to measure road surface evenness.
- Laser camera of 64 kHz to measure texture.
- Inertial unit formed by two gyroscopes and three accelerometers.
- Global Positioning System (G.P.S.).
Applications
- Measurement and recording of longitudinal profiles in 15 profile lines.
- Measurement and recording of transversal profiles.
- Calculation of surface evenness indexes (IRI; APL; PSI).
- Measurement and recording of pavement texture.
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Description
Equipment consisting on a tractor vehicle and a trailer formed by two rigid
arms resting on wheels that run along the road.
An inertial pendulum placed in one of the two arm is the fixed reference
for measuring the angular movement of the rigid arm through an angular induction
sensor.
Technical characteristics
- Testing speed of 22, 55 or 90 km/h.
- The readings are taken every 25 m.
- The data acquisition is computerized, and the computer works in real time.
- The equipment can measure wavings corresponding to wavelength between 0,6
and 30 m.
- Maximum amplitude of relative displacements of the arm which can be
measured: + 10 cm.
Applications
Evaluation of surface roughness and control of the pavement evolution. The
equipment allows the obtention of the International Roughness Index (IRI).
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Description
The Ground Penetrating Radar for Roads, based on the subsoil prospecting
geophisycs technique, by means of electromagnetic wave reflection allows to
evaluate pavement layer thickness, without contact, measuring the time intervals
between the echoes originated in the interfaces, and reaching a high level of
efficiency. The equipment is set on a vehicle and surveying can be carried out
without disturbing the normal traffic flow.
Technical characteristics
- The equipment has two pairs of bistatic TEM horn antennas with 1 GHz
working frequency, two monostatic antennas of 500 MHz and a Global Positioning
System (GPS). It can work with up to four data channels simultaneously.
- The signals reflected by the pavement can be filtered and amplified, in
real time, and can be monitorised.
- The maximum surveying velocity is 80 km/h.
- The minimum distance between scans is 25 cm, using only one antenna and
moving the vehicle at a maximum speed of 60 km/h.
- The approximate capacity, for data acquisition, is 400 km/day.
Applications
- Measurement and recording of pavement layer thickness.
- Detection of inside discontinuities and anomalies of pavements (structural
changes, high moisture, etc.).
- Surveying in specific road sections, and systematic survey of road
networks (Pavement Management System).
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Description
Simple mechanic deflectometer. A lever, hanged from a frame, transmits the
vertical deflection of the test point to a comparator.
Technical characteristics
- Frame: Support beam of the measurement lever and the comparator.
- Measurement lever 3,6 m long.
- Comparator : Device with divisions of measure of 0,01 mm, and total range
of 12 mm.
- Testing sensor: metalic piece that lies on the ground at the test point.
Applications
- Static determination of the elastic deflection of the pavement.
- Determination of the deformation produced by the load, related to the fixed
test point.
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Geometric equipment for the measurement of pavement surface roughness.
It is formed by eight lined-up wheels, linked by swingletrees, and a free
wheel in the middle of the others, lined-up with them. The testing speed is
about 2-8 km/h, and the data recording is computerized.
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Description
The Dipstick (Digital Incremental Profiler) is a high precision electronic
equipment that evaluates the superficial regularity of pavements.
It measures and records, automatically, in the memory of an incorporated
microcomputer, the difference of heights between separate points 250 [mm],
pivoting successively around its two paws of support. The registered elevation
data, is processed through a program, in order to obtain the International
Regularity Index (IRI).
It is prepared for manual use and needs only one operator.
The Road Research Center has two pivoting profilometers equipments which
technical characteristics are mentioned below:
Technical characteristics
Dipstick
- Measuring system through a tight gifted box of two paws of support with
0,25 m distance between them.
- Programmed calculator Radio Shack TRS-80 for data capture and storage.
- Batteries for Power Supply.
- Stick of operation.
- Capacity: 200 m/day.
DS 2000
- Measuring system through a tight gifted box of two paws of support with
0,25 m distance between them.
- Programmed calculator MininoteTM 3000 for data capture and storage.
- Batteries for Power Supply.
- Stick of operation.
- Capacity: 200 m/day.
Auxiliary elements
- Calibration plate.
- Battery charger.
Applications
- Measure and recording of the superficial regularity of pavements.
- Obtention of the profile of a pavement section.
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Description
Portable percussion sounding apparatus, which provides impact by means of a
sliding hammer that falls from a certain height onto a striking plate. The
energy is transmitted through a steel rod to a conical tip that penetrates into
the ground.
Technical characteristics
- Sliding Hammer: falling steel weight, 8 Kg
- Falling height: 575 mm
- 16 mm diameter steel rod, 800 mm maximum penetration into the ground (400
mm extension rod).
- Tempered steel conical threaded tip, 20 mm diameter, 60º cone angle
Applications
Used on granular pavement layers
- Evaluation of in situ shear strength
- Determination of layers thickness
- Evaluation of the bearing capacity of each layer traversed (correlation
with CBR)
- Evaluation of mechanical properties of layer materials (correlation with
E moduli)
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