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The Idiots' Guide to Highways Maintenance
Copyright © 2000/13, C.J.Summers

CORES TAKEN FROM VARIOUS TYPES OF ROAD PAVEMENTS, A CLOSE STUDY
If any one tells you they have no records on a particular road pavement they are only telling you half the truth.

You may not be able to determine the points in time when particular events took place in the history of the road pavement and you may not have the costs of the relevant repairs or procedures that took place.

But nearly everything else you will be able to determine by the cross section through the road itself.

You are able to determine the various layers, the thickness, and the actual materials themselves by isolating particular layers and analysing them, and you can even reclaim the binder and determine its penetration and softening point.  

Just about everything is possible if you have the will and the resources, and of course the knowledge of how to go about things.
Your Materials Engineer should be able to assist in these matters.


THE DETAIL SHOWN IN THIS SELECTION OF HIGHWAY PAVEMENT CORES WILL GIVE GOOD INSIGHT IN TO THE NATURE OF ROAD PAVEMENT CONSTRUCTION,
 AND THE TYPE OF MATERIALS USED,
ALL THE VARIOUS MATERIALS CAN BE ISOLATED AND TESTED IF REQUIRED.

Core from "evolved" road pavement
Core from purposely designed road pavement

Asphalt material with gravel aggregate, concrete roadbase
Semi flexible road pavement with lean concrete roadbase

Core investigating serious cracking in road pavement
Core taken from dense macadam surface course
Above is a picture of a 200mm. core of 30% 14mm. design hot rolled asphalt, if you look closely on the top (in fact the bottom) of this core you will see a slight indentation from a wheel track test, it clearly passed. 
Note, the bulk of the matrix is sand, bitumen and limestone filler.

Core from 10mm. open graded macadam surface course
Core from 10mm. stone masic asphalt surface course
There should be no voids in a true stone mastic asphalt, as shown in the image above the voids should be filled with mastic.
The mastic consisting of bitumen (50pen. most often specified), usually with a small percentage (0.3% often specified) cellulose fibres to improve aggregate coating and to prevent binder drainage, and some smaller grit that is permitted in the overall grading of the aggregate.

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