目前台灣熱拌瀝青混凝土中，再生瀝青混凝土粒料(Reclaimed Asphalt Pavement， RAP)的最高取代率僅為 40 %；另一方面，雖然冷拌再生瀝青混凝土可 100 % 使用 RAP 作為粒料來源，但受限於材料成本且僅能應用於底層，其消耗量仍不足以完全去化每年道路養護與鋪面工程持續產生的龐大 RAP 數量。因此，若能將 RAP 100 % 應用於路基填方，不僅可有效提升其再利用率、解決堆置問題，亦可兼顧節能減碳與循環經濟目標，本研究即基於此目的而開展。本研究採用國內不同地區之 RAP 材料，依其堆置方式分為粗刨除料、細刨除料及未篩分刨除料三種類型。於實驗室內進行加州載重比(CBR)試驗以評估其承載能力，並配合現地試鋪驗證其作為道路路基填方材料之可行性。實驗室試驗結果顯示，100 % RAP 之最佳含水量介於 4 %～7 %，CBR 試驗結果約介於 16～28 之間。若將所得之 CBR 值依美國瀝青協會(AI IS-181)分類標準，可歸類為良好至優良之路基材料。在現地驗證部分，本研究採用 Clegg 衝擊錘(ASTM D5874)與輕型落重撓度試驗(ASTM E2835)來評估現地成效。結果顯示，RAP 路基之衝擊值（Impact Value， IV）與動態變形模數（Dynamic deformation modulus， ELWD）均高於原土層，顯示鋪設 RAP 後可有效提升路基之承載能力。此外，當 RAP 路基之壓實度達 95 % 時，其對應之 IV 值約為 18；而 IV 值 18 所對應之 CBR 約為 23 %。綜合實驗室試驗與現地驗證成果，顯示 100 % RAP 應用於路基具有高度可行性，值得未來進一步深入研究。;Taiwan’s specifications limit hot-mix recycled asphalt to a maximum of 40 % RAP. Although cold-mix recycled asphalt concrete can use 100 % RAP as aggregate， its application remains limited by material costs and is restricted to base layers. The total volume of recycled material is still insufficient to accommodate the RAP continuously generated from road maintenance and pavement rehabilitation. Therefore， using RAP as a pavement subgrade could not only increase its recycling rate and alleviate stockpiling issues but also contribute to energy conservation， carbon emission reduction， and the promotion of a circular economy. This study used RAP materials collected from various regions of Taiwan and classified them into three categories based on particle size: coarse RAP， fine RAP， and unscreened RAP. Laboratory California Bearing Ratio (CBR) tests were conducted to evaluate their bearing capacity， and field test sections were subsequently constructed to verify the feasibility of using RAP as a pavement subgrade material. The laboratory test results indicated that the optimum moisture content (OMC) of 100 % RAP ranged from approximately 4 % to 7 %， while the CBR values ranged from 16 to 28. According to the classification criteria of the Asphalt Institute (AI IS-181)， these results classify RAP as a good to excellent subgrade material. The Clegg impact hammer， per ASTM D5874， and the Lightweight Deflectometer， per ASTM E2835， were used to evaluate field pavement performance. Field tests showed that both the Impact Value (IV) and the Dynamic deformation modulus (ELWD) of the RAP subgrade were higher than those of the original subgrade， indicating that incorporating RAP can effectively improve subgrade bearing capacity. An empirical relationship between the degree of compaction and IV was established in this study. The results indicated that when the RAP subgrade achieved 95% compaction， the corresponding IV value was approximately 18. Based on the correlation equation between CBR and IV， an IV value of 18 corresponds to a CBR value of approximately 23 %. Considering both the laboratory test results and field verification findings， it is recommended that an IV value of 18 or greater be adopted as the field strength acceptance criterion for RAP subgrades. This criterion exceeds the minimum CBR requirements specified in most domestic and international subgrade standards， demonstrating that 100% RAP is a feasible material for use as pavement subgrade. Based on the above， this study is worthy of further study.
