Light
weight deflectometer or LWDs as they are called, are used regularly in road and
highway construction to determine the compaction quality of the earthworks that
is done before and during any kind of road or highway construction.
Sophisticated Instruments
The
other highly sophisticated road testing
equipment -
the Falling weight deflectometer(FWD) is an essential requirement for the road
building contractors and inspectors to get an idea about the ability of road or pavement to
handle any future expected traffic. A big advantage of using this equipmentfor
this kind of analysis is safety and ease of operation along with instant results;
it takes 28 seconds to perform the standard test.
Being
portable, the light
weight deflectometer
is favored by many road inspectors and contractors as they can get the test
results on the spot and make the necessary adjustments or corrections.It isused
to determine the dynamic modulus of deformation of soil (resilience) in the
range Evd = 15...70MN/m .The FWD
works by imparting an impulse weight simulating traffic load on the surface
being tested and measuring the deflection waves. This gives an accurate picture
of the structure of the road substrata and the surface.
Ease of Use
The waves
created by dropping appropriate weights is picked up by the geophones at the base of the falling
weight deflectometer
and the readings are communicated automatically by a communication port to a
display unit which stores and/or prints out the readings. This type of testing
allows automatic load adjustment for greater accuracy with wide load range of
0-150KN. Another advantage of using the FWD, you can repeat the tests as many
times as required, and hence cover vast stretches of road /runway at one go
