Assessment of Carbon Footprint and Emergy Vis-À-Vis Sub Grade Strength in Flexible Pavement Construction

Abstract

Construction of flexible pavements in India is increasing rapidly and causing emission of Green House Gases (GHG) into the atmosphere which in turn increases the global warming. This paper focuses on finding out the emergy, that is the embodied energy of materials and process in construction of flexible pavement and the corresponding emission caused during the entire construction. A tool model was developed in Microsoft Excel to calculate the energy and GHG emission in construction of flexible pavement. The Life Cycle Assessment in construction of pavement has been divided into four stages namely material production stage, material processing stage, transportation stage and site execution stage, and at each stage the emergy and emission are calculated. It is seen that, during the processing of material that is the process which involves the mixing of materials into asphaltic mix in central hot mix plant and during of mixing aggregates in pug mill the energy consumption and the emission are more. A case study has been done for construction of one KM of flexible pavement of 7.0 m width with constant design parameters and by varying the sub grade California Bearing Ratio (CBR) values.The result shows that the CBR values have high influence in energy and emission.