Loadman and Loadman II

Portable Falling Weight Deflectometer


Loadman is a light weight portable device for measurement of deflection caused by a falling weight inside the device. The device is easy to handle and can be used practically on all construction sites and materials under any conditions. It allows measurement of bearing capacity and compaction of construction layers and constructions in places where other commonly used measuring instruments cannot be used owing to their size, or because of the necessity to use a lorry or a van as a weight and/or transportation unit.

Loadman II is an improved version of the original Loadman. It has internal memory for saving results and an USB connector for transferring results to a computer. The Loadman II is powered by rechargeable batteries.

Measuring principle

The deflection caused by the load of a falling weight is measured by an accelerometer. The acceleration is double integrated and thus the deflection can be calculated. The measuring results are given as the maximum deflection, the calculated bearing capacity modulus E, the length of the loading impulse and the percentage (approx.) of the rebound deflection compared to the maximum deflection as well as the compaction ratio, that is the ratio of the second and further on deflections compared to the first measured deflection (effectiveness of compaction).

Range of use

Technically the device can be used on practically all kinds of construction sites to measure bearing capacity and for compaction control on bound, unbound and special layers; for example on roads, streets, brigde sites, house building sites, in trenches, on sports fields (football, baseball, tennis, golf, athletics etc.) as well as for laboratory tests of various kinds of materials.

Technical information

Values in parenthesis are for Loadman II if different from Loadman.

Total weight 16kg
Height 117cm
Diameter of loading plate 132 and 300mm
Mass of falling weight 10kg
Falling height 80cm
Operating voltage 27V, three 9V batteries (6V, NiMH batteries)
Measuring range 0.1-5mm approx.
Duration of loading / unloading impulse 25-30 ms approx.
Misc. LCD display and four buttons (alphanumeric keypad, memory, USB connection)
What's included Carrying case, 300mm plate, two hex keys (in addition, a battery charger)