Lesson 3/Learning Event 3
Learning Event 3
INSPECTING AND TESTING MATERIAL
Close cooperation should be established between the road inspector and the plant inspector so
that any change in the mixture can be made promptly. When possible, the road inspector and the
plant inspector should frequently exchange visits. If he is familiar with plant operations, the road
inspector can more easily determine if changes at the plant are necessary to improve the mix.
The plant inspector, by becoming familiar with the paving operation, can better understand the
problems of the road inspector.
Every truckload of material should be inspected as it arrives at the job site.
REASONS FOR REJECTION OF MIX
Reject a truckload of mix for these reasons:
Too hot.
Too cold.
Excess coarse (AGG).
Excess fine (AGG).
Too much asphalt.
Too little asphalt.
Excess moisture.
Not mixed uniformly.
Contamination: oil, gas, trash, dirt...
Truckloads of mix that are contaminated will be rejected.
TESTING CONSTRUCTION
Density test samples should be taken and tests performed as often as conditions require, but at
least once for every 400 tons of mix placed. To obtain a satisfactory specimen, the sample
should be taken early in the morning when the pavement is cool. Any additional rolling required
as a result of the tests should be done during the heat of the day.
A coring machine or a concrete saw may be used for cutting out the samples. Samples from a
binder or surface course should be cut out approximately one foot square, completely through the
thickness of the pavement, and removed carefully to avoid damage.
The specimen should be sent to the plant laboratory with proper identification.
If there is a nuclear densimeter, it may be used to check density.
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