ZORN Light Weight Deflectometer | ZFG (LWD)

Highly precise test technology for the dynamic plate load test to determine the deformation modulus Evd

The dynamic plate load test is a quick test to determine the load-bearing capacity of compacted materials in earthworks, foundation engineering and road construction. It is used to verify the suitability of soils and subsoils (e.g. hard core) as a foundation and makes it possible to the user to assess immediately the quality of the compaction of the courses applied; and that while they are applied.

Reliably check compaction quality

The test undertaken using the Light Weight Deflectometer ZFG is used as a standard test in all areas of road construction these days. Irrespective of whether soils are compacted using manually operated tampers and vibrating plates, or by road rollers. With a ZFG 3000 or the ZFG 3.1 from ZORN you are able to check the quality of the compacting work quickly and reliably at any time.

Light Weight Deflectometer from ZORN's own production

The reliable and consistent use of the measuring device also called a "drop plate" is regulated in Germany in particular by the Technical Testing Regulations for Soil and Rock in Road Construction (TP BF-StB) Part 8.3, in conjunction with the Zusätzlichen Technischen Vertragsbedingungen und Richtlinien für Erdarbeiten im Straßenbau (Supplementary Technical Conditions of Contract and Guidelines for Earthworks in Road Construction) (ZTV-E StB).

ZORN INSTRUMENTS also operates a calibration stand for the Lightweight Deflectometer. This stand was developed by us for the German Federal Highway Research Institute (BASt) and was the first of its type to be approved by the authorities.

You will find more detailed information on our technical service on the calibration and servicing page.

For decades, highly qualified employees from ZORN INSTRUMENTS have been actively involved in related research and standardisation forums, in Germany and worldwide. Numerous international standards such as ASTM E2835-11 or the Austria test specification RVS 08.03.04 in the meantime permit users to use the dynamic plate load test correctly in their countries and in the related conditions there.

Test specifications and contractual terms and conditions for the dynamic plate load test.

Dynamic plate load test specifications: the Lightweight Deflectometer from ZORN INSTRUMENTS meets all specifications for the correct usage of the dynamic plate load test.


TP BF-StB Part B 8.3
Road construction, Part E1 (Statistics)

Straßenbau, Tragschichten, Kanalbau (Road construction, base courses, sewer construction)

NGT 39 - Eisenbahnbau
(Railway construction)

RIL 836 Deutsche Bahn AG
Richtlinie für die Anwendung des Leichten Fallgewichtsgerätes im Eisenbahnbau (Guidelines for the use of the lightweight deflectometer in railway construction)

RVS 08.03.04 March 2008
Verdichtungsnachweis mittels dynamischen Lastplattenversuches (Compaction verification using dynamic plate load test) (Austrian test specification)

UNE 103 807-2
Spanish test specification

ASTM E2835-11

All certificates at a glance.