Highway Contractor: IC's High IQ
Highway
HighwayContractor
by Dan Brown, Contributing Editor
Smart Rollin’
The developing genius of Intelligent Compaction
I
Intelligent Compaction (IC) for hot mix asphalt is
a work in progress. IC rollers are valuable quality
control tools that go a long way toward solving the
shortcomings of the conventional process. With some IC
systems, a display screen in the operator’s compartment
shows real-time mat temperature, roller coverage of the
mat, and some indication of mat stiffness. No current IC
system, however, will directly read out mat density. We’ll
have more on that later.
There are shortcomings in the conventional asphalt
compaction process. Today, using a standard vibratory roller, a fixed number of passes are applied to the
8 July 2012 Better Roads
asphalt. The problem is that a number of critical factors
can vary during construction operations. Such factors
include support from underlying materials, lift thickness, materials type and asphalt mat temperature. The
changes in these critical factors are invisible to the roller operator during conventional compaction. The result
is that too little or too much compaction effort may be
applied to the asphalt.
The conventional density quality control process also
has shortcomings. Typically, a small number of spot
tests are run, either with nuclear gauges or core tests. A
judgment is made about the density level of the entire