結構物鋼筋保護層厚度檢測新方法

New Methods Applied in Investigation of Rebar Cover Depth

檢測鋼筋混凝土結構物鋼筋保護層厚度的方法，除了傳統的鑽心取樣外，近年來因非破壞檢測技術逐漸成熟，包含渦電流法與透地雷達法等方法，均大量應用於相關探查。惟目前常用的非破壞檢測方法仍有資料解析度不足、易受環境干擾及過度仰賴人為主觀研判等因素，造成應用上的限制。本研究採用震波測勘方法中的反射震測法與折射震測法，應用於鋼筋混凝土結構物中鋼筋保護層檢測，初步研究成果顯示表層鋼筋的反射波及折射波明顯，根據時域及頻譜資料計算求得的保護層厚度相當準確，且檢測資料同時亦可用於內部鋼筋定位。

NDT methods, such as Eddy current and GPR, have been widely used for identifying the thickness of concrete protective cover of RC structures except the coring method. However, the limitations to apply these methods are still existed due to insufficient data resolution, ambient noise interference and subjective judgment. The seismic methods, such as refraction and reflection, were adopted in this study to investigate the thickness of concrete protective cover. The results show that the refracted and reflected signals of the rebar at top layer were obvious and the thickness of concrete protective cover could be estimated from the echo time processing. The interpreted data shows good agreement with physical models in both time and frequency domain. Furthermore, the location of rebar could be also determined.