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SD Instrumentation CIST/884 Clegg Impact Soil Tester
Ruggedly Designed Tool for Checking Trench Re-instatement & Soil Strength
The GPS equipped 4.5 Kg CIST/884
Clegg Impact Soil Tester manufactured by SD Instrumentation
provides an easy and straightforward means for
measuring and controlling soil strength and
consolidation levels during trench re-instatement. The
GPS 884 readout is clamped to the guide tube and the
displayed reading is viewed from the top during use.
Single button operation design provided for easy use.
On board data logging and
data storage with wireless data transfer facilities are
provided with the CIST/884 instrument. Latitude &
Longitude coordinates of the test location are received
by the in-built GPS then stored providing users with an
accurate location reference for later viewing in eg
Google earth™. Users can download their site test
results to a PC wirelessly by Bluetooth, using the PC
software supplied with the instrument. This cable-free
operation greatly enhances system reliability.
The instrument is used to confirm uniform
compaction of over wide areas of ground, identifying
poorly compacted areas and ineffective rolling of
The CIST/884 Clegg Impact Soil Tester is a very rugged
design suitable for prolonged use in damp, dirty and harsh site
environments. The CIST/884 readout unit is made from high strength
alloy that has been proven to last for decades. The instrument runs from
2 x ‘C’ batteries for typically 12 months operation. The CIST/884 Clegg
Impact Soil Tester is a compact and reliable instrument. A wooden
Transit & Storage Case is included.
The Tester consists of a 4.5 kg compaction
hammer operating within a vertical guide tube. The Hammer falls
through the tube when released and strikes the surface under test,
decelerating at a rate determined by the stiffness of the material within
the region of impact. The readout registers the deceleration in units of
Impact Value (IV). The IV is an indication of soil strength.
Good correlation with results from
CBR tests exists. Data from the CIST/884 can be used in
a similar manner to results from CBR tests performed in
the laboratory and in the field. The CIST/884 display when
enabled by the user can directly show the %CBR result
based upon Dr Clegg’s original pioneering work.
The Clegg Test was introduced by British Gas in
the UK in 1990 following extensive laboratory and site
testing. Since then several thousands of the instrument
are now being used throughout the UK and overseas, with operators employing the
recommended test routines.
CIST884 READOUT UNIT
The Readout Unit displays readings of Impact Value (IV) and
also shows the number of times that the hammer has been
dropped during each test operation. The number of GPS
satellites detected is also displayed confirming successful
GPS location fixes.
Carrying out a test is quick
and straightforward. The
ground surface is brushed lightly with the foot to remove loose material
and the guide tube is placed in position.
The miniature high gain
GPS antenna receives the satellite signals. The hammer is raised to a
height of 450 mm as indicated on the hammer head and then allowed to
fall freely. This procedure is repeated four times, the reading achieved on
the fourth drop being recorded as the Impact Value. Software selectable
%CBR display and recording is supplied. An automatic GPS
measurement is taken with the hammer drops providing a Lat / Long fix.
Tables of target IV for a range of backfill and subgrade materials are
given in the operating manual, enabling the operator to check the
compliance of reinstatements with the specification levels.
GPS CLEGG IMPACT SOIL TESTER TYPE CIST/884 – 4.5 Kg
The Tester, described in the UK Design Manual for Roads and Bridges (DMRB) has been approved by the
American Society for Testing and Materials and a Standard, under Designation No D 5874 was issued in
1995, entitled “Standard Test Method for Determination of the Impact Value (IV) of a Soil”.
The Clegg Impact Soil Tester is designed, manufactured and marketed by S D Instrumentation Ltd (SDi,
UK) under an exclusive licence from Dr Baden Clegg, the original Australian inventor.
Please note - Product designs and specifications are subject to change without notice. The user is responsible for determining the suitability of this product.
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