Cost and Eco-Effective Cold In-Place Recycled Mixtures with Foamed Bitumen During the Reconstruction of a Road Section Under Variable Load Bearing Capacity of the Subgrade

Abstract

The development of vehicle transport, causing increased numbers of vehicles and road users as well as increased loads acting on the pavement, has a negative impact on its durability within the intended life cycle. A major part of Polish road network has severely deteriorated and requires that immediate measures be undertaken to improve the safety and comfort of users. Cold In-place Recycling with Foamed Bitumen (CIR-FB) technology uses 100% of reclaimed material by converting distressed layers into new materials for the stabilization of the subgrade and/or base courses without the need to demolish, haul and manage them. This paper presents a proposal of the reconstruction of the pavement of a road section localized in central Poland (świętokrzyskie province) using traditional and alternative materials. Cost effectiveness and ecological effectiveness of proposed technologies were compared taking into account variable load bearing capacity of the subgrade (frequent in linear construction projects), resulting from its non-uniformity. In the case analysed, due to the presence of various sands (including sand dust and same uniformly graded sand of poor compactibility), the pavement durability was estimated based on the assumption of 50MPa and 80MPa subgrade bearing capacity. It was demonstrated that, considering economy and ecology, the replacement of standard solutions based on new materials by the CIR-FB materials is the most effective way of road reconstruction with its long service life maintained.