Micro-surfacing, a modern surface-sealing treatment for road corridors, which has replaced worldwide the periodical “overlay” and repairs using bituminous concrete (BC) has been rolled out for the first time in the State.
A 200-metre stretch of the Poonthi road in the capital was subjected to micro-surfacing by Thiruvananthapuram Road Development Company Limited (TRDCL), the concessionaire of the City Road Improvement Project.
The surface-sealing treatment was used for extending the life of the road that was completed in 2007 as well as for repair necessitated by minor settlements resulting from large-scale utility excavations before the roads were developed by the TRDCL. In Kerala, with two monsoons, the technology will come in handy for the PWD as micro-surfacing can improve skid resistance, surface durability, and seal fine and medium cracks.
Instead of giving a fresh BC layer, a 4 mm to 6 mm uniform layer of a sludge like substance, made up of a special emulsion, 6 mm high quality aggregate, and bitumen, is added on the surface of the road that needs repair.
High strength
Left to solidify for around half an hour, it attains high strength, enough to allow heavy traffic through the corridor after two hours. Initially, the micro-surfaced stretch will be rough and gradually it will turn smooth.
A special vehicle is used for micro-surfacing. Through a computerised process of weighing and mixing, the ingredients are mixed and applied through a paver mechanism.
The paver unit, which is also integrated with the vehicle, can be adjusted to get the desired thickness and profile for the road. The unit can micro-surface one lane km of road with a width of 3.5 m in three hours.
“Use of expensive machinery, wastage of material and resources, and disruption of traffic can be avoided through this technology developed by Spain,” TRDCL managing director Anilkumar Pandala said.
NHAI approval
The technology has been approved by the National Highways Authority of India as a substitute for periodical overlays and also by the Central Road Research Institute.
“The work is being executed as a part of the TRDCL meeting its obligations under the 15-year concession agreement,” he added.
