Improvement of Major Road Intersections in Urban Areas by the Use of Thin Whitetopping Technology (TWT)

Whitetopping, or concrete overlay, is applied over existing bituminous pavement to improve the load-carrying capacity and ride quality of worn surfaces. It effectively addresses problems like rutting and texture loss at a lower cost than bituminous solutions. In Solapur city, many flexible pavements at major intersections are deteriorating due to insufficient thickness and poor drainage. This situation leads to higher maintenance and vehicle operating costs, as well as safety issues for pedestrians, especially in hot climates where bitumen is more prone to damage. This study examines a major distressed intersection for whitetopping design based on pavement performance studies, including the Benkelman Beam Deflection Study. We evaluated the feasibility of different concrete options, such as normal concrete, polypropylene fiber reinforced concrete, and fly-ash concrete (20% replacement) as topping materials. A cost-benefit analysis considered the entire life cycle expenses to find the most effective overlay solution. After detailed investigations, including topographical studies, road condition assessments, traffic analyses, deflection studies, and material investigations at the major intersection, we propose a 200mm thick Thin Whitetopping Pavement with 20% cement replacement by fly ash. Although the upfront construction cost of a concrete overlay is much higher than that of a bituminous overlay, the life cycle cost analysis indicates that using fly ash makes the concrete overlay more economical over time. This leads to a net savings of 29.82% for concrete overlay with fly ash over the project's lifespan, making it a financially smart choice for long-term infrastructure investments. Additionally, we recommend geometric corrections to improve visibility and facilitate turning. The turning radius has been increased from 15m to 30m. We also propose a 5.5m additional lane for left-turning vehicles to ensure smooth traffic flow during peak hours. New traffic islands are included to manage movement, reduce congestion, and provide refuge for pedestrians.