Research On Greenhouse Gas Emission Evaluation System For Asphalt Pavement Construction

The greenhouse gas emissions quantity in China is huge, reducing the emission ofgreenhouse gas is an important direction of Chinese energy strategy adjustment. Pollutantsand greenhouse gas emissions in the transportation industry accounted for the entire societyemissions in China by8%, which is high energy consumption and the key field of energysaving and emission reduction. The rapid development of highway construction leads to greatconsumption of the building materials resources such as stone, lime, cement, asphalt,chemical additives and so on. Moreover, it could not be ignored that mixing, transport, pavingand rolling processes in road construction bring much energy consumption and emissions. Atpresent, there is no clearly quantitative conclusions of the greenhouse gas emissions of roadengineering construction. The evaluation system and determination method of greenhouse gasemissions for pavement construction stage is lack, and also the comparative analysis ofemissions among different pavement materials and construction techniques. Therefore, it isimportant and urgent to research greenhouse gas emission evaluation system and method ofpavement engineering construction in the background of the current economy of energysaving and emission reduction.By the life cycle assessment, the paper collects and survey construction process, rawmaterials, production process and the corresponding production machinery and equipmentparameters in the new semi rigid base asphalt pavement, summarizes greenhouse gasemissions and exhaust gas types, cleares the main effect of greenhouse gas emissions factorsin the construction phase for asphalt pavement surface and base course, and then determinesthe greenhouse gas emissions quantitative evaluation indexes are divided into the primaryindex and secondary index. The primary index is the universal and general index, and selectcarbon dioxide equivalent of each development stage as a representative index value,secondary index reflects is expediently targets in various stages of asphalt pavementconstruction emissions, mainly refers to the various machinery and equipment energyconsumption and emissions of material itself in the production process.The paper chooses different measurement methods by dividing the evaluation index.Index type means generalized and specific index. Generalized index refers to a wide range of applications, not only road industry. It can be quantitative through the existing research results.Specific index is specific, and usually quantities by calculation or measurement, includingenergy consumption method, investigation method, material balance method and fieldmeasurement method. Based on the index calculation, the paperthe gives a statistical modelfor the greenhouse gas emissions of asphalt pavement evaluation system.The paper structures greenhouse gas emissions evaluation system of asphalt pavementbased on evaluation index, calculating method and the model, presents the method todetermine the criteria to evaluate the greenhouse gas emissions of asphalt pavementconstruction. The evaluation system boundary coveres direct greenhouse gas emissions andenergy indirect emissions involved in all stages of production and construction sectors of theasphalt surface and semi-rigid base. The evaluation system frame comprises the primary indexlevel, secondary index level and variable level, The variable level is correspondinginfluencing factors for every secondary index. The paper expounds the calculation methodand process of asphalt pavement of greenhouse gas emission evaluation system through theanalysis of a typical example evaluation.The paper clears the focus on energy consumption saving and greenhouse gas emissionreduction for asphalt pavement and puts forward some measures. Asphalt surface should focuson the energy control in mixing stage, the good choices are using energy-efficient machineryand equipment,and adopting WMA or CMA by low heat energy. For semi-rigid base, theemphases is production of the raw materials stage, it is useful of choosing cement productionby energy-efficient method, or using other base forms with less cement.Based on the greenhouse gas emissions evaluation system of Asphalt pavement, thepaper analyses the greenhouse gas emissions among HMA, WMA and CMA surface layer andquantities the emissions difference between cement stabilized gravel base course and thegraded crushed stone base construction. The results show that energy saving8.14%on perkilometer of warm mix asphalt mixture surface layer than per kilometer of hot mix asphaltmixture layer, and8.26%reduction in greenhouse gas emissions per kilometer, cold mixasphalt mixture surface layer decreases36.42%energy consumption and36.36%greenhousegas emissions than per kilometer of hot mix asphalt mixture layer. the graded crushed stonebase per kilometer energy comsumption saving67.87%and greenhouse gas emissions reducing89.30%by cement stabilized macadam base.Results of the paper fill the gaps in evaluation of greenhouse gas emission process ofasphalt pavement construction in China, provide the basis for the consideration of savingenergy and reducing emissions of different pavement materials and construction process, andhave a good theoretical significance and application prospects.