Heavy Weight Deflectometer (HWD) for High‐Load Pavement Testing – Structural Evaluation for Airports & Heavy‐Duty Infrastructure ↓
Deliver precise structural evaluation, comply with international standards, and optimize maintenance.
Structural evaluation for high‐load pavements (airfields, heavy‐duty roads)
The Heavy Weight Deflectometer (HWD) is engineered to evaluate the structural integrity and load‑bearing capacity of high‑load pavements. It simulates extreme impact loads – reproducing the load of a Boeing 747/777 or Airbus A380, as well as heavy freight trucks, without damaging the surface. Designed for demanding environments, the HWD provides precise, repeatable deflection data that support runway ACR/PCR (new ACN/PCN) reporting, pavement life expectancy forecasting, and targeted maintenance planning with minimal operational downtime.
You need it when:
- Assessing airfield infrastructure: High‑load structural testing on airport runways, taxiways, and aprons in compliance with FAA/ICAO standards (e.g. ACN‑PCN classification via ACR/PCR calculations).
- Analyzing heavy‑duty networks: Evaluating container ports, industrial zones, military facilities and other infrastructures subjected to extreme axle loads, to ensure they meet structural performance requirements.
- Quality assurance on heavy pavements: Verifying structural strength and compaction on newly constructed or rehabilitated heavy- duty roads/pavements to confirm they meet design criteria and load capacity standards.
- zing maintenance strategies: Using HWD deflection data to feed pavement analysis tools (e.g., Dynatest ELMOD software) for backcalculation of layer moduli, residual life estimates, and cost‑effective rehabilitation planning for high‑load pavements.
Heavy Weight Deflectometer
Dynatest developed the first commercially available Heavy Weight Deflectometer (HWD). The HWD is highly versatile and can be used to test both rigid paver block and flexible pavements on roads and airports. The HWD can apply a loading in the range of 30-320kN, enabling it to simulate vehicle loading up to the most extreme aircraft wheel load such as the Boeing 777, the Airbus 340, or 380.
The output from the deflectometer can be used:
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To determine the layer of failure and the optimal restoration solutions.
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For quality control or existing and new pavement construction
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Improve and understand pavement modeling
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In pavement management
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In pavement research
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See the HWD in Action – Real Data, Real Results.
Our HWD system is crafted for high-accuracy deflection measurements, empowering asset management, design, and rehabilitation strategies. As ACR/PCR standards evolve, our technology elevates pavement assessment, providing actionable data for critical infrastructure.
Optimize your testing strategy with our solutions.
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Key benefits
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Dynamic loading enables mechanistic-empirical analysis of the pavement layers and the determination of optimum rehabilitation strategies
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Automated and rapid structural pavement testing
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Determines the layer of failure, rather than determining simply the bearing capacity
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QA/QC of newly built pavements
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Compares a range of rehabilitation options, including plane off and recycling rather than just applying overlays
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The Dynatest HWD provides accurate, reproducible, and repeatable data
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Automated and real-time monitoring of the load cell, geophones, and data variations ensures high quality of collected data
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Uses mechanistic analysis allowing testing of most pavement structures
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The HWD is used worldwide from the hottest and driest deserts to the humid tropics and the cooler polar regions
New bearing capacity classification ACR/PCR
The pavement bearing capacity is a key point when it comes to the safety of runways.
The International Civil Aviation Organization (ICAO) has introduced a new classification ACR/PCR which will take effect in November 2024.
ACR stands for – Aircraft Classification Rating and tells how different aircrafts affect pavements.
PCR stands for – Pavement Classification Rating and shows how much weight the pavement can carry.
By using this new ACR/PCR classification, airports can improve their operations, enhance safety, and plan better pavement maintenance.
Get a closer look
Meets ASTM D-4694, D-4695 and equivalent standards
Peak load range approximately 30 to 240kN / 320kN
Up to 15 seismic deflection sensors
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Standard Equipment
- 4 segmented loading plate with swivel commodates uneven or rutted pavement surfaces
- 7 or 9 deflection sensors (geophones)
- Air/Pavement Temperature Sensors
- Distance Measuring Instrument (DMI)
Available Options
- Global Positioning System (GPS)
- Camera system for plate location or Right of Way Imaging
- On board generator for standalone operation
- Trailer mounted light(s) or strobe(s)
- Rear or rear and transverse sensor extension bars
- Ground Penetrating Radar (GSSI or IDS)
- Spare parts kit
- Tool kit
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 HWD 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 repair (M&R), the LCCA (Life Cycle Cost Analysis) module allows the user to select the optimal M&R solution for a pavement section according to cost/benefit ratios
FAQ HWD
A Heavy Weight Deflectometer (HWD) is a non-destructive pavement testing system used to evaluate the structural condition of roads, airfields, and other heavily loaded pavements. The system applies a controlled impulse load to the pavement surface and measures the resulting deflection basin. Engineers use this data to assess structural capacity, identify weak pavement layers, support rehabilitation planning, and evaluate long-term pavement performance. The Dynatest HWD is designed for applications requiring higher loading levels than those typically used in conventional road pavement testing.
Both HWD and FWD systems evaluate pavement structural condition by measuring pavement deflections under a dynamic load. The primary difference is the load capacity. The Dynatest HWD can apply loads from 30 to 320 kN, making it suitable for heavily loaded pavements such as airport runways, taxiways, aprons, and other high-capacity infrastructure. The higher load capability allows engineers to evaluate structures subjected to heavier traffic and aircraft loading conditions.
An airport should consider using an HWD when evaluating the structural condition of runways, taxiways, aprons, or other pavements subjected to significant aircraft loads. HWD data can support pavement rehabilitation planning, remaining-life assessments, overlay design, and Pavement Classification Rating (PCR) calculations when combined with ELMOD pavement analysis software. The ability to apply loads up to 320 kN makes the HWD suitable for assessing heavily loaded airport pavements.
The Dynatest HWD supports a dynamic load range from 30 kN to 320 kN (6,600–71,800 lbf). Multiple loading configurations can be used to generate load levels suitable for different pavement structures and engineering objectives. This load range enables testing of both road pavements and heavily loaded airfield pavements using the same platform
Yes. The Dynatest HWD is designed for structural pavement evaluation on both roads and airports. The system can be used for highway investigations, rehabilitation projects, airport pavement assessments, overlay design studies, and pavement management programs. This flexibility allows organizations to use a single testing platform across multiple infrastructure types.
The HWD can be used wherever detailed structural pavement information is required. Typical applications include highways, airfield pavements, runways, taxiways, aprons, rehabilitation projects, overlay design investigations, pavement management programs, and quality assurance activities. The equipment is particularly valuable when evaluating pavements exposed to heavy wheel loads or demanding operational conditions.
A deflection basin describes how a pavement structure responds to a dynamic load. By measuring deflections at multiple locations around the loading plate, engineers can evaluate structural behavior, identify weak pavement layers, estimate layer stiffness, and assess overall pavement condition. Deflection basin data forms the foundation for advanced structural analyses performed in software such as ELMOD.
Backcalculation is an engineering process used to estimate pavement layer stiffness from measured deflection basins. By comparing measured pavement responses with calculated responses, engineers can determine layer moduli and evaluate the structural condition of individual pavement layers. This information supports rehabilitation planning, overlay design, and remaining-life assessments.
ELMOD is Dynatest's pavement analysis software, designed to work directly with HWD measurements. The software supports backcalculation of layer moduli, overlay design, remaining-life assessments, seasonal correction, load transfer analysis, pavement design, and airport pavement evaluation. Together, the HWD and ELMOD provide a workflow that takes pavement data from field testing to engineering decision-making.
PCR stands for Pavement Classification Rating. It is a methodology used in airport pavement evaluation to assess pavement capacity in relation to aircraft operations. ELMOD supports PCR calculations according to FAA and ICAO methodologies, helping airport operators and engineers evaluate pavement capability and support planning decisions for airfield infrastructure.
Overlay design requires an understanding of existing pavement structural condition. HWD measurements provide information about pavement response, structural capacity, and layer behavior. When analyzed in ELMOD, this information can be used to determine overlay requirements and support rehabilitation strategies based on measured pavement performance rather than assumptions alone.
HWD testing provides structural condition data that can support pavement management programs. The collected information can be used to identify weak sections, prioritize maintenance activities, estimate remaining pavement life, and support long-term infrastructure planning. Structural information complements surface condition data and helps organizations make more informed maintenance and investment decisions.
The Dynatest HWD can support up to 15 deflection sensors (geophones) simultaneously. Measuring deflections at multiple offsets from the loading plate provides detailed information about pavement response and enables a more comprehensive evaluation of pavement structural behavior.
The HWD incorporates a load cell for load measurements and supports up to 15 geophones for pavement deflection measurements. The system also includes air temperature and surface temperature sensors for recording environmental conditions during testing. These measurements help provide the information required for structural pavement evaluation and subsequent analysis.
The foldable trailer option is designed to simplify transportation and deployment. When folded, the trailer has reduced transport dimensions and is designed for air transport. The configuration can be packed on a single pallet, making it easier to move equipment between projects or international locations.
The Dynatest HWD is supported by Dynatest Data Collection (DDC) software for field operations and ELMOD for pavement analysis. DDC supports data collection, visualization, GPS integration, and real-time calculations, while ELMOD provides advanced structural analysis, including backcalculation, overlay design, remaining-life assessment, and PCR calculations.
Dynatest offers equipment training covering system setup, configuration, measurement procedures, troubleshooting, and preventive maintenance. Training is typically conducted on-site and is normally completed over five working days. ELMOD training is also available either online or on-site, depending on customer requirements and purchased software modules.
The HWD supports a relative dynamic calibration verification procedure that allows users to verify measurement performance under actual testing conditions. The procedure uses multiple geophones and comparative measurements to confirm measurement consistency and accuracy. Calibration verification forms an important part of maintaining reliable structural pavement data.
Routine maintenance includes the preventive maintenance procedures covered during operator training, together with regular verification of equipment condition and calibration performance. Dynatest also provides service support and training to help customers maintain long-term equipment performance and measurement reliability.
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