FastFWD

Fast Falling Weight Deflectometer

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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FastFWD Brochure
FastFWD Brochure US

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

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 the 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

New method for in-situ Accelerated Pavement Testing

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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