Durable and Cost Effective Concrete Overlay on City Bituminous Roads: Whitetopping

Binod Kumar, Scientist, CRRI

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Introduction

Concrete is a very durable material for the construction of roads and highways. Several highways, expressway, and city roads have been constructed with cement concrete in the recent past in India. Cement concrete roads offer many advantages like long life of more than 30 years, minimum maintenance requirement, and 10-15 % fuel saving for heavy vehicles. Cement concrete has been used for the construction of new roads, highways and also for the rehabilitation of existing distressed bituminous pavements.

Rutting and potholing of bituminous pavement is a real problem in hot climate like India's, with heavy truck loads, operating under frequent start/stop conditions. Concrete overlay is commonly applied where rutting and potholing 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. USA and Europe have been using whitetopping in its various forms 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 two decades. 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 in Pune, Mumbai, Delhi, Nagpur, Jaipur, and Bangalore in the last few years. The performance of these sections has been found to be excellent.