Whitetopping Durable and Cost-effective Solution for City Roads

Binod Kumar, Sr. Pr. Scientist CRRI, New Delhi

Cement Concrete

Concrete is a very durable material for the construction of roads and highways. Cement concrete has been used for the construction of new roads, highways and also for the rehabilitation of existing distressed bituminous pavements. Several highways, expressways and city roads have been constructed with cement concrete in the recent past in India. Cement concrete roads offer long life of more than 30 years with minimum maintenance requirement. Rutting of bituminous pavement is a real problem in hot climate like India, with heavy truck loads, operating under frequent start/stop conditions. It is commonly applied where rutting of bituminous pavements is a recurring problem. Concrete overlays offer the potential for extended service life, increased structural and functional capacity, reduced maintenance requirements, and lower life-cycle costs when compared with bituminous overlay alternative.

Concrete overlays have been used to rehabilitate both the existing bituminous (flexible) pavement since 1918 and existing concrete pavement since 1913. Whitetopping in its various forms have been used in the USA and the Europe on Airports, Inter-state roads, Primary & Secondary Highways, Local Roads, Streets and Parking lots to improve the performance, durability and riding quality of deteriorated bituminous pavement surfaces. There has been a renewed interest in Whitetopping, particularly, in Thin & Ultra-Thin Whitetopping during the last decade. This has been possible due to several successful high-profile projects executed in USA and Europe. Their effectiveness has further renewed interest in them because they satisfy the demand caused by rapidly deteriorating highways confronted with limited fund availability. Whitetopping of all types, viz; Conventional Whitetopping, Thin Whitetopping (TWT) and Ultra Thin Whitetopping (UTWT) offer immense potential as a rehabilitation strategy for Indian roads. Several successful projects have been executed at Pune, Mumbai, Delhi, Nagpur, Jaipur and Bangalore in the last few years. The performance of these sections has been found to be satisfactory.

Whitetopping
Whitetopping is defined as a Portland Cement Concrete (PCC) overlay constructed on the top of an existing bituminous pavement. Whitetopping is thus PCC resurfacing (overlay) as a rehabilitation or structural strengthening alternative on bituminous pavement. The PCC overlay may or may not be bonded to the layer below. Whitetopping involves placing a concrete overlay on distressed bituminous pavement surface.