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Clegg Impact Soil Tester

Impact Soil Tester 20kg for testing of flexible pavements from on top of the seal coat of heavily sealed roads. Wherever, whenever there is evaluation or construction of earthworks, road works or airstrips, the Clegg Impact Soil Tester offers quick, useful and convenient soil strength / stiffness and uniformity testing. 

The basic principle behind the Clegg Impact Soil Tester is to obtain a measurement of the deceleration of a free falling mass (Hammer) from a set height onto a surface under test. The impact of the hammer produces an electrical pulse, which is converted and displayed on the Control Unit in units of gravities "G" or tens of gravities "CIT". Reference ASTM test methods D5874 and F1702.

The standard test protocol developed by Dr. Clegg is to drop the hammer four consecutive times on the same location with the highest value result in the series taken as the Peak Clegg Impact Test result. Since that time, other test protocols have been used based on the materials under test and the application. These other protocols vary the Hammer drop height or use the average result in place of the peak. The Clegg offers the convenience of rapidly scanning compaction variation over large areas. In research studies, 250 tests were performed with the Clegg in a half-day. Irrespective of meeting a density specification for roadworks* and trench reinstatement, etc, insufficient strength / stiffness can lead to failure, typically if the material is too wet prior to opening to traffic or sealing. One of the uses of the Clegg Hammer is to monitor the improvement in strength / stiffness through drying out so that a certain minimum Clegg value is obtained in order to help prevent such failures as a result of too much moisture, be it residual moisture from the compaction process, flooding, precipitation or groundwater – where, for example, undetected inflow from the shoulders or underground springs can lead to serious problems. The rapid and simple nature of making Clegg Impact Tests allows for large areas to be scanned rapidly by one person. The portable nature of the Clegg Impact Soil Tester allows for testing in remote or difficult to access areas. The non-destructive nature of the method obviates driving rods down into a finished layer which could lead to potholing.  

For more information, price and availability please call 08 9409 4058 or email us

 Impact Soil Tester 4.5kg  non destructive Clegg Impact Soil Tester 

The 4.5 kg "Standard" Clegg Impact Soil Tester was the first Clegg Hammer developed by Dr. Baden Clegg in the 1970's. It was initially conceived to relatively quickly, easily and cost-effectively test the strength/stiffness characteristics of soil materials (including soft rocks and lightly stabilised materials) as used in road construction, for standard lift thicknesses, but has turned out to be the "general purpose" Clegg. It is based on the instrumentation of a "modified proctor" laboratory compaction hammer. The Hammer mass is 5 cm in diameter at 4.5 kg and is dropped from a set height of 45 cm. The weight of the guide tube and metre is approximately 2 kg.
The Australian shipping case weighs approximately 7 kg. The total weight is around 14 kg. Instrument height is 70 cm and the guide tube is 15 cm in diameter. The shipping case is around 22 cm by 25 cm by 80 cm. The output at the fourth drop of the standard Clegg Hammer when dropped from its standard height is known as the Clegg Impact Value (CIV), where the output is in Clegg units, i.e. where 1 Clegg unit equals 10 gravity units with the resulting decimal fraction truncated. The Impact Value is displayed directly and instantaneously on the Hammer’s meter upon completion of the test. The Clegg Impact Test can be performed by the supervisor himself or by the man on the job. Sensible application at the time of construction can reduce the risk of costly overworking or reworking.

Shown above is a black-painted mild steel drop-hammer (e.g. Model 883)

Shown above is a stainless steel drop-hammer (e.g. Model GTM-SS-E)

For more information, price and availability please call 08 9409 4058 or email us




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