Ruggedly Designed Tool for Checking Trench Re-instatement & Soil Strength
The 4.5 Kg CIST/883 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 883 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
features provided with the CIST/883 instrument.
Users can download their test results from site to
PC, wirelessly, using the PC software supplied with
the instrument. This cable-free operation greatly
enhances system reliability compared to cabled
The instrument is used to confirm uniform
compaction of over wide areas of ground,
identifying poorly compacted areas and ineffective
rolling of materials.
The CIST/883 Clegg Impact Soil Tester is a very rugged design suitable for prolonged
use in damp, dirty and harsh site environments. The CIST/883 readout
unit is made from high strength alloy that has been proven to last for
decades. The CIST/883 battery compartment, sealed to IP67, is fitted
with 2 x AA batteries for typically 12 months operation. The CIST/883
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/883 can be used in
a similar manner to results from CBR tests performed in
the laboratory and in the field. The CIST/883 display can
directly show the %CBR result based upon Dr Clegg’s
original pioneering work. This feature is simply selected
from the PC software provided.
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.
CIST883 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.
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 digital readout is located on the guide tube, shown
above, during testing allowing easy use as there is no need to hold
the readout in the hand. 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 Quality
Assurance (Q. A.) Readout firmware can advise the user of a failed
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.
CLEGG IMPACT SOIL TESTER TYPE CIST/883 – 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 Simon Deakin Instrumentation
(SDi, UK) under an exclusive licence from Dr Baden Clegg, the original Australian inventor.