There are many factors which affect asphalt concrete roads. Many of the conventional quality control and quality assurance criteria and the tests applied to the asphalt concrete mix don’t satisfactorily simulate the conditions to which the asphalt concrete road is subjected under traffic. Principal among these being the various forms of disintegration which occurs and the effects of traffic and the weather. As a result, some roads, meeting the standard specifications, may still degenerate to such an extent that the roads become unsafe or uncomfortable due to the occurrence of undesirable irregularities, and this may occur over a time span much shorter than might have been predicted.

For example, 210mm thick National Highway Authority (NHA) road, underlain by 150mm thick aggregate base course, flood emergency reconstruction project (FERP) at quite a few sections is prematurely showing signs of a distress even before its completion. This is likely due, but not limited to use of inappropriate quality materials, lack of testing compatibility, and lack of an appropriate performance-based specifications. The concerned quarters, including international experts are requested to explore enhance the criteria of the current practice in order to improve the performance and the durability of roads. This is very vital for proper utilization of both local and foreign funds.

ABDULLAH MEMON,

Hyderabad, September 6.