Fast Falling Weight Deflectometer
The Fast Falling Weight Deflectometer (FastFWD) is 5 times faster per drop than the original Falling Weight Deflectometer (FWD). The FWD is designed to impart a load pulse to the pavement surface simulating the load produced by a moving vehicle. The load pulse is measured by a load cell with a resolution of 0.1 kPa, and the pavement response is recorded by up to 15 deflection sensors with a resolution of 0.1μm.
The post-processing software (i.e. Dynatest ELMOD- Evaluation of Layer Moduli and Overlay Design) can be used to back-calculate the pavement layer moduli based on the impact load and surface deflection basin. The results can effectively be used for the evaluation of pavement structural conditions and overlay design based on empirical or mechanistic-empirical pavement design guides.
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Fast Falling Weight Deflectometer video
Watch the video here and see how fast a Fast Falling Weight Deflector really is and what benefits it provides.
Key features and benefits
- The Fast Falling Weight Deflectometer (FastFWD) is 5 times faster per drop than the Falling Weight Deflectometer
- No hydraulics
- Same sensor setup and user interface as with the Falling Weight Deflectometer
- Passes AASHTO R 32 and the UK Correlation trial
- 75% more test points per hour or 45% less traffic exposure
- Lower maintenance cost
- Ease of training operators and service personnel
- Consistent data with Dynatest Model 8002 FWD
- Upgrade capability from Model 8002 FWD to FastFWD
Get a closer look
Electro-mechanical system with ease of maintenance
Peak load range approximately 4 to 120kN / 150kN
Meets ASTM D-4694, D-4695 and equivalent standards
Fast movement due to electric motor, 3-drop testing performed in less than 15 seconds
Up to 15 seismic deflection sensors
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Standard Equipment
- Four segmented loading plate with
swivel accommodates uneven or rutted
pavement surfaces - Air/Pavement Temperature Sensors
- Distance Measuring Instrument
(DMI) - On board generator for standalone
operation
Advances
- A single direct drive, 3-phase torque
motor and ball screw assembly
drives the new system replacing the
hydraulic system in FWD - Very fast—up to 160 test points per hour
- 8002 FWD’s can be upgraded to the
new FastFWD Model 8012 system - Less maintenance costs—no hydraulic
system - Less impact due to reduced survey time
Available Upgrade Options
- Folding trailer for ease of shipment
- Global Positioning System (GPS)
- Camera system for plate location or
photo-logging - Trailer mounted light(s) or strobe(s)
- Rear or Rear & Transverse Sensor
Extension Bars - Ground Penetrating Radar
- Spare parts kit
The use of Falling Weight testing
Data collected from the Dynatest FastFWD can be used for determination of structural capacity of in-service pavements to analyze the physical properties of the pavement. When analyzing the data from the Dynatest FastFWD with the ELMOD software, it is possible to obtain information about the condition of the road, such as: surface layers, sub grade layer, layer moduli, layer types, thickness, range of moduli, Poisson’s ratio and bearing capacity.
This information can be used to estimate overlay requirements, remaining life of the pavement and an effective creation of a Pavement Management Plan.
ELMOD Software - only available for Dynatest Equipment
- Evaluation of Layer Moduli and Overlay Design
- Dynatest’s ELMOD software may be used for the analysis and design of flexible, rigid, and composite pavements
- Allows quick data reduction and analysis of FastFWD load/deflection measurements
- Capable of backcalculation of the layer moduli, for a typical drop sequence, in less than a second
- Fast calculation of the seasonally adjusted moduli, residual life of the pavement, and required overlay thickness for a given service life
- For maintenance and rehabilitation (M&R), the LCCA (Life Cycle Cost Analysis) module allows the user to select the optimum M&R solution
for a pavement section according to cost/benefit ratios - For analysis of airfield pavements, the optional PCN module calculates PCN in accordance with the ACN/ PCN method, as described in the ICAO and FAA design manuals
Fast Falling Weight Deflectometer and Accelerated Pavement Testing
Accelerated Pavement Testing (APT) has since the beginning of the year 1900 helped to create innovation and understanding of pavements during accelerated testing and is one of the valuable tools that can be used to predict and validate performance. The possibility of using the FastFWD for in-situ Accelerated Pavement Testing (APT) to study pavement deterioration will shorten the gap between the Heavy Vehicle Simulator (HVS) and small-scale laboratory test methods.
The FastFWD (with an APT application package) has proven to be able to be used as an intermediate tool, between small-scale laboratory tests (bending beam, shear, and triaxial tests) and full scale accelerated pavement tests. Several tests have been conducted with great success. Read more about this application in the brochure or application note below.
Download Brochure
FastFWD Accelerated Pavement Testing
Download Application Note
Watch our video about The Fast Falling Weight Deflectometer in APT
The FastFWD (with an APT application package) has proven to be able to be used as an intermediate tool, between the small-scale laboratory tests (bending beam, shear, and triaxial tests) and full scale accelerated pavement tests. See more in this video.
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