Research on early degradation mechanism of road pavement due to interlayer debonding and its countermeasures

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04655
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 22010:Civil engineering material, execution and construction management-related
• Research Institution: National Institute for Land and Infrastructure Management
• Principal Investigator: WAKABAYASHI YUYA 国土技術政策総合研究所, 道路構造物研究部, 研究官 (00776099)
• Co-Investigator(Kenkyū-buntansha): 前川 亮太 国立研究開発法人土木研究所, 土木研究所(つくば中央研究所), 主任研究員 (20455497) ; 川名 太 東京農業大学, 地域環境科学部, 教授 (90349837)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: アスファルト舗装 / 層間はく離 / FWD / ひずみ / 促進載荷 / 多層弾性解析

Outline of Final Research Achievements

First, stresses in the pavement interior are calculated by multi-layer elasticity analysis when interlayer debonding occurs, showing that damage can occur that is not considered in current pavement design. The results also show the change in deflection and the error in the inverse analysis when interlayer debonding occurs.
In addition, test pavements were constructed to simulate several interlayer bonding conditions, and their deterioration progress and internal behavior were compared immediately after construction and after accelerated loading test. At the end of the study period, no clear difference in deterioration was observed, and the effect of interlayer bonding conditions on pavement durability was not clear. In the section where interlayer debonding was simulated, it was found that the interlayer bonding occurred due to loading, and that a review of the conditions was necessary.

Free Research Field

舗装工学

Academic Significance and Societal Importance of the Research Achievements

多層弾性解析による応力解析結果により，層間はく離が生じた場合，従来の設計で想定するようなアスファルト混合物が一体の場合と，舗装内部の挙動が異なることやそれにより設計で想定する損傷と異なる損傷が生じる可能性を示した．
これは，一般的なアスファルト舗装のみならず，新しい構造の舗装の設計においても同様に留意すべき点であり，検証の必要があることを明らかにした．
また，試験舗装では層間接着条件が耐久性に与える影響について明確にすることはできなかったが，ひずみ計による舗装の挙動の観測が妥当であることが明らかになった．本手法は様々な舗装構造に応用が利くものであり，今後活用が進むものと考えられる．