國道三號大溪龍潭段剛柔性鋪面生命週期成本分析與碳排放量比較

Abstract

國道三號大溪龍潭段63K+935~73K+185間（總長9.25公里）為國內第一次於道路主線段上大規模鋪設剛性鋪面，本路段自民國82年8月通車至今已屆22年，根據國道歷年來維護資料顯示此路段維修頻率低，且未曾辦理大規模重新鋪築。紀錄顯示此剛性鋪面路段所經歷的主要維護，以提升鋪面平坦度為要，包括通車初期於民國84年與後續使用階段間於89年、90年與94年曾進行部分路段鋪面刨磨工程，此外則為接縫填縫劑之例行性更換及零星板塊挖除修補等局部養護。相較於前後相鄰約同等長度之柔性鋪面，均曾依其損壞狀況不同分別進行1至3次不等之全面重新刨鋪，於養護規模上似有差異，故本研究擬以實際案例探討兩種不同鋪面材料型式於生命週期內之總成本與碳排放量。 為以量化方式驗證剛性與柔性鋪面之工程成本與碳排放量差異，本研究蒐集國道三號大溪龍潭段及其前後相鄰約同等長度之柔性鋪面自通車至今近22年之大量工程標案資料，建構一套合理的資料架構；並將未結構化之工程標案資料彙整為可供本研究分析使用之結構化資料。所得之剛性鋪面與接鄰柔性鋪面歷年維護資料，利用生命週期成本分析（Life cycle cost analysis，LCCA）與生命週期評估(Life cycle assessment, LCA)之方法，計算評估剛、柔性鋪面之初始建設成本、維護成本、用路人成本與部分生命週期階段的碳排放量，進行兩種鋪面之總成本效益與碳排放量比較。本研究分析結果可供高速公路主管機關參考，並於未來於選定鋪面類型時，將經濟與環境之觀點同時納入，以永續之觀點進行決策。

The 9.25 km (5.8 mile) Daxi-Longtan section of National Freeway No. 3 was the first large scale concrete pavement of major highway in Taiwan. Based on the recorded maintenance data for the past 22 years since its opening, concrete pavement has shown much lower frequency of maintenance and consequently lower maintenance costs than that of asphalt pavement. The major maintenance works involve diamond grinding, full depth and partial depth patch, joints resealing, and a few slab replacements. This study conducted life cycle cost analysis (LCCA) and life cycle assessment (LCA) on the concrete pavement and two conjunctive sections of asphalt pavement with the same length, one at each end of the concrete pavement section. The LCCA approach considers not only direct agency costs (initial construction costs and maintenance costs) but also extra user costs induced by congestion at maintenance work zone. The LCA mainly focused on CO2 emission of paving materials preparation, transportation, and construction equipment operation. The results show that for the first 22 years, the ratio of life cycle costs of concrete pavement over that of asphalt pavement is 1.11. On the other hand, the ratio of CO2 emission of concrete pavement over that of asphalt pavement is 1.34. Researchers also conducted the forecasting analysis for a total life of 40 years. It is found that both types of pavement have almost the same life cycle costs and CO2 emission. Since a relatively large portion of the user costs and CO2 emission of concrete pavement are caused by traffic congestion during maintenance, it is believed that both extra user costs and CO2 emission can be reduced significantly if the fast-track concrete pavement maintenance method can be adopted.