當混凝土結構物產生裂縫後，經過長期雨淋之後常有滲水之情況發生，此情況也將遭成混凝土結構物內鋼筋之鏽蝕，更嚴重將影響到整體混凝土結構物之強度。在過去已有許多非破壞監測方法及研究來感測混凝土內部之濕度，然而，常遇見之問題有感測儀器昂貴、需要利用纜線連接、需更換電池等。這些問題使得人力及設備維修成本增加，且若結構物本身建於環境不佳人不易到達之位置，將造成監測人員在監測時的工作危險增加。 本論文研究提出以Sensor code為基礎的特高頻無線智慧濕度感測器應用於因混凝土裂縫之滲水感測系統，此系統也將透過破壞指標的方式作為混凝土是否有滲水的判斷機制。希望能透過此研究提供另一種感測系統用於未來之結構健康監測上並解決上述所提出之問題。此研究也提出了以Poly Lactic Acid (PLA)為原料製成3D列印保護殼，提供感測器於混凝土內抵抗高鹼性環境及外力之能力。感測器在黏貼於3D列印保護殼內情況下埋入混泥土圓柱試體內，最遠達到3公尺的感測距離。而在具有鋼筋之一般常用配比之混凝土梁內雖感測距離下降，其感測距離仍達到50公分。在兩種試體情況下，本論文提出之滲水感測機制皆證明為有效的，且其判斷滲水之可信度極高。然而，其中訊號強度及頻率破壞指標尚不能作為判斷機制之一，未來仍須透過修正破壞指標及進行更多實驗來增進其判斷能力。 ;Water penetration of concrete due to cracking often causes reinforcement corrosion and degradation of the strength of the concrete structure. This thesis, therefore, proposes and tests a sensor code-based UHF RFID smart tag seepage sensing system. Similar sensor code-based smart tags have been applied in many fields, but never previously embedded in concrete for seepage detection. This research also proposes using 3D-printed cases made of Poly Lactic Acid (PLA) to protect smart tags from outer force impact and high alkaline environment. Experiments that involved embedding this case in a cylindrical concrete found that it provided excellent protection under compression, while the maximum read range of the smart tag from within the case was more than 3 meters, i.e., 10 times farther than the uncased tag achieved. In further experiments, 3D-printed cases with smart tags attached inside were embedded in a general beam, with reinforcement bars included. The read range decreased but still got a minimum promising read range of 50 cm, which is still a feasible distance for long-distance monitoring. According to the results, the sensor code damage index indicates the appearance of the seepage with high accuracy, in both cylindrical concrete and beam specimen. However, the RSSI and frequency index fails to be as a sensing indicator. More specimens should be tested and the damage index should be revised to improve the sensing mechanism. In sum, the results of the main experiment indicate that the smart tag’s sensor code damage index can reflect the effect of water seepage due to cracks in concrete effectively.
