{"id":16322,"date":"2026-06-18T08:17:20","date_gmt":"2026-06-18T08:17:20","guid":{"rendered":"https:\/\/lwd-test.com\/?page_id=16322"},"modified":"2026-06-18T08:17:20","modified_gmt":"2026-06-18T08:17:20","slug":"faq","status":"publish","type":"page","link":"https:\/\/lwd-test.com\/it\/faq\/","title":{"rendered":"FAQ"},"content":{"rendered":"\t\t
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Frequently asked questions - FAQ<\/h1>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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1. What does the TERRATEST 9000 LWD Light Weight Deflectometer measure?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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A Light Weight Deflectometer is one of the fastest and most efficient tools for evaluating soil compaction and load-bearing capacity directly on site. Contractors, civil engineers, and quality control personnel use this dynamic testing device to verify whether earthworks and foundation layers meet project specifications before construction continues.<\/p>

The measurement process is simple and can be completed within just a few minutes. First, the Lightweight Deflectometer is placed on the surface to be tested. After connecting the device to the smartphone app via Bluetooth, the operator can immediately begin the testing procedure.<\/p>

During the test, a series of controlled impact loads is applied to the ground surface. The integrated geophone continuously record the resulting settlement and deformation behavior of the tested material. After each impact, the smartphone display shows the measured deflection in millimeters as well as the corresponding deflection curve. This allows the operator to visually assess the response of the soil, aggregate, or unbound layer in real time.<\/p>

Once the measurement sequence is completed, the application automatically calculates and displays the EVd value in MPa. This dynamic deformation modulus provides valuable information about the stiffness and bearing capacity of the tested layer. The results can be stored digitally, transferred to a computer, or incorporated directly into professional compaction reports for quality assurance and documentation purposes.<\/p>

The Light Weight Deflectometer is widely used in earthworks, road construction, railway projects, pipeline installation, utility trench construction, landscaping, and sports field development. Because measurements can be performed directly on the construction site, project managers receive immediate feedback on compaction quality and can identify potential deficiencies before costly delays occur.<\/p>

One of the major advantages of a modern Lightweight Deflectometer is the significant reduction in dependence on external testing laboratories. Site personnel can perform routine quality control independently and obtain reliable results in less than two minutes. This allows construction activities to continue without waiting for laboratory schedules or external inspectors.<\/p>

In many cases, the investment in a Light Weight Deflectometer is recovered within a relatively short period through reduced testing costs, improved productivity, and fewer project interruptions. Combined with digital data collection, GPS positioning, smartphone connectivity, and automated reporting functions, the device has become an essential tool for modern construction quality control and compaction verification.<\/p>

Important: A project-specific correlation<\/a> between the dynamic results obtained with the Light Weight Deflectometer and the static plate load test should always be established where required by project specifications, standards, or local regulations. This ensures reliable interpretation of the measured EVd values and supports compliance with quality assurance requirements.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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2. Is the Light Weight Deflectometer test method recognized by national and international standards?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Yes. The Light Weight Deflectometer test method is recognized by several national and international standards. The most widely used specification is ASTM E2583-07 (2015), which is accepted in many countries worldwide. Additional standards include CEN\/TS 17006, BS EN 1924-2 (Great Britain), UNI 11531-1 (Italy), TPF 5 (285), NCHRP 10-84, and CD 225. These standards define the testing procedures and requirements for evaluating soil compaction and bearing capacity using a Light Weight Deflectometer.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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3. How does a Light Weight Deflectometer work?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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A Light Weight Deflectometer works by dropping a calibrated falling weight onto a loading plate placed on the soil surface. The impact generates a stress pulse that simulates traffic or construction loads. The device measures the resulting ground deflection and automatically calculates the Evd value, providing an immediate assessment of soil stiffness and compaction quality.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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4. What is the Evd value?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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The Evd value or E-modulus is the dynamic deformation modulus expressed in MPa. It indicates the stiffness and load-bearing capacity of the tested soil. Higher Evd values generally indicate better compaction and stronger ground conditions.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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5. How long does a Light Weight Deflectometer test take?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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A complete Light Weight Deflectometer test typically takes less than two minutes. The procedure includes positioning the device, performing the required impact drops, and automatically calculating the test result. This makes the LWD one of the fastest methods for non destructive field compaction testing.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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6. What are the advantages of a Light Weight Deflectometer compared to a static plate load test?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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The Light Weight Deflectometer offers several advantages:<\/p>

  • Results within minutes<\/li>
  • No nuclear device<\/li>
  • One-person operation<\/li>
  • No reaction vehicle required<\/li>
  • Portable and lightweight equipment<\/li>
  • Lower testing costs<\/li>
  • Immediate quality control on the construction site<\/li><\/ul>

    For these reasons, the LWD has become one of the most popular tools for routine compaction control.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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    7. Which industries use a Light Weight Deflectometer?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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    Light Weight Deflectometers are widely used in:<\/p>

    • Road construction<\/li>
    • Earthworks<\/li>
    • Railway construction<\/li>
    • Pipeline and utility installation<\/li>
    • Fiber optic and broadband projects<\/li>
    • Landscaping and sports field construction<\/li>
    • Airport and pavement projects<\/li><\/ul>

      Any project requiring verification of soil compaction and bearing capacity can benefit from LWD testing.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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      8. Can a Light Weight Deflectometer replace a static plate load test?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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      In many projects, the Light Weight Deflectometer is used as a rapid quality control tool. However, local regulations may require a correlation between the dynamic Evd value and the static plate load test results. The exact requirements depend on national specifications and project standards.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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      9. What is the maximum measuring depth of a Light Weight Deflectometer?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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      The effective measuring depth depends on soil type and stiffness but is typically up to approximately 60 cm (24 inches). The test primarily evaluates the stiffness of the compacted layers directly beneath the loading plate.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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      10. Can the TERRATEST 9000 LWD be operated by a single person?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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      Yes. The TERRATEST 9000 LWD Light Weight Deflectometer is specifically designed for one-person operation. All measurements, calculations, GPS data collection, and report generation can be performed directly using the smartphone app.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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      11. How often should a Light Weight Deflectometer be calibrated?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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      According to ASTM E2583-07 (2015), a Light Weight Deflectometer should be recalibrated every 12 months. Regular calibration ensures accurate measurement of soil deflection and guarantees reliable test results.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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      12. What is the calibrated measuring range of the TERRATEST 9000 LWD?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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      The TERRATEST 9000 Light Weight Deflectometer is calibrated within a deflection range of 100 to 1200 microns (0.1 to 1.2 mm). This range defines the calibrated operating limits of the instrument and covers the vast majority of soil compaction applications encountered in civil engineering and construction projects.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"

      Frequently asked questions – FAQ 1. What does the TERRATEST 9000 LWD Light Weight Deflectometer measure? A Light Weight Deflectometer is one of the fastest and most efficient tools for evaluating soil compaction and load-bearing capacity directly on site. Contractors, civil engineers, and quality control personnel use this dynamic testing device to verify whether earthworks 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