Why are many roads (mostly flexible pavement) in the most developed nations having pavement distresses?

In case of our country (Poland) the main problem is poorly constructed subbase. Flexible pavement is vulnerable to ground deformations such as deformations caused by heavin soils or mining-induced deformations. If the subbase layer is too thin there is no buffer to compensate this influence and considerable strains appear in the pavement layer. This leads to fructure of the pavement material.

Obviously, this has economic implications as a lot of work and money is needed for repair and maintenance. Moreover, it has - let's say - social impact. The quality of engineering structures defines, in a way, the economic level of the country and it's always a shame for the citizens when their structures fail.

And what is the reason for all that? I'm afraid that the main problem is corruption because I know that the level of education is very good and engineers - both designers and contractors - are aware of the technical issues.

I have written a paper on this subject. I hope it can answer some of your questions:

also this second one may help:

In our country pakistan due to corrupt polititians only 30% of the amount is loaded to the road work while 70% is load to bab(politians). They call it do easy load to baba to build a road

Flexible pavements, in general, are naturally prone to those distresses you mentioned if there is not a well-defined and executed periodic maintenance plans. In my opinion, there is a little, if anything, to do with the technical expertise available in the developing countries. The problem is in the cultural framework under which those engineers and experts are performing. Public work is very much fragmented in those countries in the sense that different government agencies are operating in their own small worlds with little or no coordination among them. You might find a well-designed pavement structure that is failing prematurely, not necessarily because of corruption, but because there was no proper quality control exercised during construction due to certain bureaucracy from the client side (which is most likely the government) or there is no system of monitoring truck weights (no weigh-in motion facilities) that ensure load restrictions are properly followed.

In certain parts of the world, there is of course the week economies and the inability to properly enhance and then utilize available local materials which might forces the engineers to make compromises when bringing a pavement structure to existence

You have some good points in your essay, specially with regard to the cultural network. I disagree on putting quality control away from corruption because is the easiest way for a government official to be corrupt. If the quality control, which is quiet standard for pavement construction, is simply handled carelessly there are substantial earnings for the contractor and for the corrupt agent in not enforcing adequate control and then point fingers to bureaucracy for the lack of enforcement, even though both parties are readily aware that exercising the controls are not all that hard or difficult to document in terms of reference ensuring quality will be enforced during construction.

As far as pavement being adequate, there are technical resources for successful designs.

Then they toss vague statements to the lean public that are likely to believe that the public administration is guilty. In a way it is but not because of it is too difficult, because the cultural framework deliberately allows the loopholes to favour the corruption.

In Srilanka most of the road construction activities are highly politicized. Hence applying deep theories are not possible. Like Mohamad mention the case in Pakistan here the extent of ratio is slightly less. Any way Aria's articles are very useful thanks

You may like to have a look at a couple of recent contributions which on the basis of the hostility of the review process may just contain some new and helpful explanations - see also http://toheroa-jim.blogspot.co.uk/2012/02/references-cited-in-asphalt-cracking.html for some further musings on asphalt failures.

You might like to take a look at http://toheroa-jim.blogspot.co.uk/2012/02/references-cited-in-asphalt-cracking.html

You may find some of the musings at the following blog helpful: http://toheroa-jim.blogspot.co.uk/2012/02/references-cited-in-asphalt-cracking.html

there are several reasons for distress problem in developing countries even in developed countries.. the leading country in the world USA recognized the early distresses problem and try to solve it by introducing SUPERAPVE system. in the developing country: still there is lack in the performance evaluation in the lab and asphalt concrete mix design..as well as the poor quality control during construction process. sometimes all above reasons combined with excessive axle loading which exceeds the allowable limit and the severe climatic conditions during hot summer days...all these reasons lead to premature failure of asphalt concrete pavement..regards