Micro-surfacing is a high-performance cold mix application treatment wherein a thin layer of bituminous surfacing is applied to the existing road surface, for preventive maintenance as well as periodic renewal treatment, thus increasing the life of the existing road. It is especially recommended on deteriorated roads that are not yet bad enough to warrant full reconstruction. Micro surfacing is versatile and can be used on various types of roads. This is basically a renewal treatment of flexible and sometimes rigid pavements, now gaining importance in India too.
Micro surfacing process uses a mixture of polymerized bitumen emulsion, specially graded fine aggregates, cement, water and additives, mixed homogeneously on site in a special stand-alone machine.
Owing to the application of a thin layer, the application warrants a special grade of Polymer Modified Bitumen (PMB) Emulsion which rectifies surface defects including minor cracks, dry & hungry surfaces, wear and tear due to traffic movement. The thickness of the applied layer depends on the traffic density the road sees, and is clearly explained in the IRC: SP:81-2008 specification guidelines for micro-surfacing. The Clause 512.5.1 of the MoRTH specifications outline conditions for Microsurfacing, including minimum pavement and air temperatures, and wet surface conditions.