Construction and performance evaluation of experimental sections laid on urban roads using stone matrix asphalt mixtures

Mastic asphalt (MA) is a plastic, voidless and impermeable surface which is laid specially on bridge decks and locations such as bus-stops, intersections and roundabouts as a wearing surface in India. MA surfaces have tendency to develop joints opening, peeling off and sinking of coarse aggregate which makes the road surface slippery and causing severe cracking due to thermal induced stresses. Stone matrix asphalt (SMA) can be an alternate solution to overcome various problems being encountered through the use of MA. A research project was undertaken at Central Road Research Institute (CRRI), New Delhi, India to design and evaluate SMA mixtures with the aggregates found in the Delhi region. It was found in the laboratory that SMA mixtures gave better resistance to permanent deformation (rutting) and provided good skid resistance. A trial section was constructed for the first time in India, in September-October 2006 at two intersections, followed by MA on another intersection on the same road which is a major arterial road. Two types of cellulose fibres in the form of pellets were used as stabilizing additives in SMA mixture.