Life cycle inventory of bitumen in South Africa

Abstract

Road pavements are constructed of bulk raw materials such as aggregate, cement, bitumen and water. The environmental, social, and economic impacts of the materials and processes should be quantified and monitored towards the optimisation of pavement design. At present, no such protocol is in place in South Africa. This paper proposes a framework for the development of a pavement life cycle assessment model, starting by documenting the life cycle inventory for bitumen, one of the leading environmental and social burdensome materials used for pavement development. This inventory acts as the first building block in the development of a life cycle assessment model by evaluating and delineating primary flows (inputs of materials and energy and outputs of pollution) related to the supply chain of bitumen in South Africa. The primary flows are represented by indicators which measure their quantitative impacts. The inventory provides impact category indicators for environmental and social related emissions, energy- and water-use and currently excludes other indicators such as emissions to water, waste generation, jobs creation and economic transformation, amongst others. These indicators are omitted due to lack of quality data at present and difficulty in the quantification of impacts, but recognition is given to their relevancy and importance. The approach is envisioned to function as the first version of a living protocol that will be improved on through further research. Although the primary target audience is South African road authorities, the approach can be adapted for use in any country.