Life Cycle Assessment Of Bitumen Pavement Materials

At present, the global resources and energy are increasingly scarce. However,the construction of asphalt pavement spends a lot of non-renewable resources andenergy and discharge a variety of waste gas and dust, which make serious impact onthe environment. In the past, qualitative analysis is used to evaluate the resourceconsumption, energy consumption and environmental emissions of asphalt pavementconstruction which lack of quantitative analysis. Therefore, it is necessary to makequantitative analysis on resource consumption, energy consumption andenvironmental emissions of asphalt pavement during construction process, and buildscientific and reasonable evaluation index system for the energy saving and emissionreduction of asphalt pavement.For this situation, life cycle assessment (LCA) is used to calculate the life cycleinventory of asphalt pavement construction after collecting basic data. Then themain environment load stage and environment impact types during life cycle ofasphalt pavement are determined after comprehensive evaluation. Furthermore, LCAmethod is adopted to investigate the environment load and environment impacttypes of asphalt concrete produced by different regeneration technologyes(plant mixthermal regeneration, plant mixed cold regeneration, geothermal heat regeneration,and in situ cool regenerated technology) and systematically analyze the differencesof four kinds of regeneration technology on the environmental impact. The relevantperformance of the recycled asphalt concrete achievements of previous scholars isinvestigated. The usability difference of recycled asphalt concrete per environmentalimpact is calculated after combining with the environmental impact results. On thisbasis, the integrated value index P/IC (C: Cost, P: Performance, I: Impact of theenvironmental) of the recycled asphalt concrete is calculated. The regenerationasphalt concrete evaluation index of life cycle assessment are put forward and thegreen evaluation system is established using the analytic hierarchy process throughanalyzing asphalt pavement material from raw material acquisition to waste andregeneration process of the entire life cycle according to life cycle analysis method. Research results show that:(1) LCA is used to analyze the resources, energy consumption andenvironmental emissions of asphalt concrete in life cycle. The results show thatnon-renewable resources influence is the main environmental pressure in the courseof the asphalt pavement construction. The non-renewable resource consumption,greenhouse effect and acidification effect mainly take place in raw materialproduction phase, and type of photochemical smog and human health mainly takeplace in material transportation phase.(2) The results of evaluating the four different regeneration technology usingLCA show that the effect of plant mix thermal regeneration technology onenvironmental impact of asphalt concrete during life cycle is the biggest, thenfollowed by plant mixed cold regeneration technology, on-site cold regenerationtechnology and geothermal renewable technology.(3) Combined with the physical properties of asphalt concrete and theproduction cost, the old material blending rate is lower, the comprehensiveperformance of recycled asphalt mixture is better only taking the road performanceof asphalt pavement into consideration. But after considering environmental impactand cost of production, with the increase of dosage of old material, the integratedvalue index rise. The use of the regenerative agent show significant effect onimproving the comprehensive index of regenerated asphalt.（4）According to the principle of evaluation index system of energyconservation and emissions reduction of asphalt pavement, the resource utilization,energy consumption and environmental emissions and pavement technology areselected as first-level indicators and preliminary established the evaluation indexsystem of energy conservation and emissions reduction of asphalt pavement usinganalytic hierarchy process.