Carbon footprints calculator of highway pavement rehabilitation: The quantification of carbon emissions per unit activity

Abstract

Carbon dioxide that emitted throughout the construction lifespan is crucial from development of design, construction, up to demolition stage. Focusing in the rehabilitation of highway pavement, the activities that normally involved are from milling, roller up to dumping the wastes asphalts. The aim of this paper is to estimate the carbon footprint emission in unit of tonnes for carbon dioxide equivalents (t CO2-eq/km-lane). The case study involved based on five selected projects for north–south bound expressway of Malaysia. The results show that highest carbon footprint were from the Mill and Pave 250 mm (MP 250) with 117.94 t CO2-eq/km-lane. This is due to its depth of pavement with 140 mm dense bituminous macadam, 60 mm asphalt concrete base course and 50 mm asphalt concrete wearing course as compared as other Mill and Pave. The result followed by MP 200, MP 110 and MP 50 at 95.19, 54.10, and 27.37 t CO2-eq/km-lane respectively. The critical activities involved during the construction shows the asphalt concrete production as the highest generation of emission with 53.78 t CO2-eq/km-lane, followed by lorry transportation of asphalt waste, lorry transportation of asphalt concrete, fuel consumption from machineries, neomed coat, and water consumption with the value of 28.58, 24.50, 10.83, 0.23, and 0.01 t CO2-eq/km-lane respectively. The results from this study considered as references guidelines for carbon footprint calculator to calculate emission as compared to other expressway in Malaysia.