Environmental Impact Assessment Of Concrete Pavement And Asphalt Pavement Based On LCA

Since reform and opening up, China's highway infrastructure construction has achieved a leap-style development. While highway construction was promoting economic development, it also brought many environmental problems. Therefore, the environmental impact of highway construction should be fully considered at the same time with the pursuit of profits in highway construction process. From the exploitation of raw materials to the abandonment of pavement, each stage of a road needs to consume energy and discharge greenhouse gases and other pollutants. To quantify the energy consumption and emissions of pavement can help designers to realize the details of the energy consumption and emission and some potential influencing factors of each stage. It is advantageous for the designer to identify problems originally and conduct reasonable, scientific, systematic energy conservation and emissions reduction plan in the design process.In order to solve the high-quality asphalt shortage and to improve the Portland Cement Concrete Pavement's drawback including poor driving comfort and difficult repair, new cement concrete pavement, Continuously Reinforced Concrete Pavement become the new focus. Although the advantage of the continuous reinforced concrete pavement in the use performance has been demonstrated, its performance on environmental impact are rarely studied. Therefore, this article will use life cycle assessment (LCA) method to compare the environmental effects of continuous reinforcement concrete pavement and widely recognized asphalt pavement. In this paper, two kinds of pavement life cycle are divided into four stages, including raw material production stage, pavement construction stage, use and maintenance stage, and structure demolition stage, etc. this paper choose reasonable calculation methods for quantitative analysis of energy consumption and emissions of each stage. The calculation method of energy consumption including quota method and IRI-speed-fuel consumption model. Quota method is suitable for calculating the energy consumption of machine of road construction phase, maintenance of the operation and maintenance phase and structure demolition phase. IRI-speed-fuel consumption model is used to calculate fuel consumption increase due to road conditions change during operating maintenance phase. Emission factor model can be used to calculate air emission.After life cycle inventory data analysis of two kinds of pavement, it can be seen that although the energy consumption of continuous reinforced concrete pavement in the whole life cycle is greater than the asphalt concrete pavement, as a result of continuous reinforcement concrete pavement's long service life, continuously reinforced concrete pavement's annual energy consumption after converted is lower than the energy consumption of asphalt concrete pavement. From the perspective of energy saving, continuously reinforced concrete pavement's green degree is higher than that of asphalt concrete pavement. This will support the continuous reinforced concrete pavement's promotion in our country. The environmental load of operation and maintenance phase in both two kinds of pavement is the biggest of all. It occupy 88.14% energy consumption in continuously reinforced concrete pavement and 73.3% in asphalt concrete respectively in total energy consumption. Therefore, to guarantee the road is in good condition, not only can ensure the vehicle's steady state forms but also can make an important contribution to energy saving and emission reduction. In the environmental emissions of two kinds of road, the emission size of the three categories of emissions is global warming>acidification effect> particle emissions. Compared with the global warming emissions, acidification effect and particle emissions often differ two and four orders of magnitude. This illustrates that among the entire life cycle of road, the emission of greenhouse gases is most prominent. So, reducing greenhouse gas emissions should be the main focus to reduce emissions.The research results of this study are conducive to the proposal and application of new technology used for energy conservation and emissions reduction. It also can help government departments to formulate relevant laws, regulations and policies related to energy saving and emission reduction.