The Estimation of the Self-healing Repair Technology for Cracked Underground Structures on the Urban Highway System

During the service life, the durability of a concrete structure is always an essential issue in civil engineering. Past researches indicated that the presence of a crack exacerbates the rate of carbonation progress in a concrete structures, leading to the corrosion of embedded rebar or tendons. Such phenomenon may alter the engineering properties, structural capacity, and deteriorated levels, which in turn affect the durability, water leakage, water-tightness of a concrete structure, as well as air tightness to withstand challenges in service. In general, the preferred countermeasure of a large scale underground concrete structure to prevent water passing through construction is waterproof sheet membrane. However, the remedial action to be taken to prevent leakage into crack areas are often inaccessible. In addition, Japan society entered the age of declining birthrates and working age population over a decade, which implied the capital for the infrastructure maintenance and renewal has dramatically declined. Therefore, an appropriate self-healing material for repair, maintenance and rehabilitation tasks is significant undertaking.