noun
reconstruction; rework
Refers to doing construction work again, often to fix defects or redo a project. Common in civil engineering and building contexts.
橋の再工事は来月から始まる予定です。
The reconstruction of the bridge is scheduled to start next month.
欠陥が見つかったため、道路の再工事が必要になった。
Because defects were found, rework of the road became necessary.
再建 is broader, covering rebuilding of structures or organizations, while 再工事 is specifically about construction work.
Compound of 再 (re-, again) and 工事 (construction work). The derivation is transparent from its components.