Carbon Emission and Cost Analysis of Using Hybrid Fibre White Topping Overlays—A Road Rehabilitation Feasibility Study

Abstract

White topping is a popular road rehabilitation technique that uses Portland cement concrete overlay on top of any existing bituminous pavement. However, this often results in additional cost and carbon emission escalations which complicates market useability of the product. The current study aims at comparing carbon emission and manufacturing cost of concrete topping mixes with three different fibre types. The study optimises the benefits and promotes the use of effective materials in sustainable road rehabilitation. Samples with polyolefin-twisted (F2) fibres indicated least carbon emission escalation while the sample with polypropylene (F3) exhibited least cost escalation with 0.75% and 7.17% from the control sample respectively. A multi-objective genetic optimisation study was conducted to identify the mix designs with least carbon emission and production cost escalations. Sensitivity analysis illustrated that transport distance is a critical contributing factor for production cost while carbon emission is highly sensitive to emission factors for transport and cement production. These results indicate the importance of considering locally available materials and clean energy for production processes. Future research can be focused on exploring the long-term environmental and economic benefits including the durability characteristics to benchmark the sustainable benefits of using waste fibre materials in the mix.

Keywords

• road rehabilitation
• cost
• carbon emissions
• optimisation
• white topping