Proper Soil Compaction is Vital for Quality Road Construction

"The Indian market, today, has a complete range of road construction equipment which are contemporary in design by way of technology and deliver the desired results. But still, roads and highways are bound to fail prematurely due to various reasons such as wrong selection & usage of the equipment on the project sites, lack of structural strength owing to improper soil stabilisation, inadequate compaction at base and sub-base levels, and improper laying of asphalt and compaction thereof," says Mr. Rajinder Raina, General Manager-Marketing, Escorts Construction Equipments (ECE).

The last 18 months have seen a surge in demand for vibratory compactors, both soil as well as asphalt. The demand has been driven by highways and rural roads. The projects have been greenfield as well as brownfield comprising widening of roads. There are some prestigious road projects which have been started off and many more are on the drawing board. Demand for compactors is here to stay.

In the past two decades, we have constructed expressways, highways, and dedicated freight corridors, but the quality of the roads is yet to hit global levels because SOPs are not adhered to in toto. I have been very closely observing the execution of Delhi-Agra highway for the past 2 years. The quality of work is below par. The base and sub-base of roads are being constructed using ash and soil but the way soil and ash is being mixed/blended is so arbitrary that in no way will it achieve the designed structural strength. There is no adjustment of moisture content, and to top it all, the compactors used are inappropriate. On a few flyovers along the road, one can see a mini tandem roller being used for compaction of soil at the grade separation level. Furthermore, the temperature of the asphalt is not being measured/monitored. One of the site supervisors had no clue as to why a mini TVR was being used, nor about the importance of asphalt temperature.

The moot point being made is lack of quality execution, supervision, and regular measurement of compaction. The subject road is bound to fail prematurely because of lack of structural strength owing to improper soil stabilisation, inadequate compaction at base and sub base levels, and improper laying of asphalt, and compaction thereof. This observation is limited to non-compliance of SOPs.

There are all types of compactors available in the Indian market today, which are contemporary in design by way of technology that can deliver the desired results. Soil compactors ranging from 10-12.5 tons are available from various manufacturers including Escorts (EC-5250 and EC-2420, drum drive and pad foot variants of these models) asphalt compactors from 9-11 tons (HD 85), Mini Tandem Vibratory Compactors (EC 3664, pneumatic tire rollers et al). The availability of complete range of equipment in the Indian market place is certainly not the problem. It is the usage of the right equipment on the project sites. Having crossed an aggregate of 100000 kms of national highways, we are yet to deliver quality matching the Autobahn (Germany). It is time that NHAI raised the bar, particularly of highways and expressways and settle for nothing less than the world-class quality.

The road construction equipment manufacturers in India can offer just about everything that takes to make state-of-the-art roads as also relay some of the old roads. However, the EPC contractors, in particular, have to raise the bar a few notches and NHAI and MoRTH have to ensure that the end specifications are delivered not at the end of the project but at every stage of the road under construction.

We, at Escorts, are committed to keep upgrading our compactors to ensure that these are able to deliver the best, not only in India but in other countries as well.

This essay is limited to compaction on the roads only, however, there are so many other aspects to road construction, which in turn, entail a host of equipment like Motor Graders, Scrappers, Soil Stabilisers, etc.