Page 5 - RoadCem in Road Reconstruction & Rehabilitation_Neat
P. 5
ROAD RECONSTRUCTION WITH ROADCEM
To understand why a high dynamic modulus increases the life span of the road, we have to
take a look at the repetitive loadings which are typical for all roads and consider the cyclic
dynamic loading which is acting through the asphalt to the road base.
The force “F” is acting only at one point, under the tyre of the vehicle which is moving along the road.
If we look at one segment of this road, then for this segment an alternating stress occurs. The segment is
deflected under the force “F”, but when the force has passed the force on the segment is relieved and the
deflection returns to where it was. Then this section is loaded again, relieved, loaded and so on in a continuous
cyclic process.
Unfortunately, neither normal road graded stone base, nor standard cement bound base are able to stand this
cyclic loading over long periods of time. If a load is too high, then the elastic limit of the base is exceeded
meaning it will no longer spring back to its original position. This effect can be calculated using Liners strain
analysis.
When this happens we end up with a plastic deformation of the road surface typically resulting in rutting or other
types of deformation.
This can be mitigated and the engineering properties of the road can be improved.
