Observation of Corrosion Process of Reinforcing Steel

Mohammad Ismail, and Dina, Erica, and Rosly Abdul Rahman, and Sabirin Ikhsan, (2005) Observation of Corrosion Process of Reinforcing Steel. Malaysian Journal of Civil Engineering, 17 (1). pp. 13-22.

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Affiliations

Universiti Teknologi Malaysia, Faculty of Civil Engineering, Dept. of Structures and Materials.
Universiti Teknologi Malaysia, Faculty of Civil Engineering, Dept. of Structures and Materials.
Universiti Teknologi Malaysia, Faculty of Science, Dept. of Physics.
Universiti Teknologi Malaysia, Faculty of Science, Dept. of Physics.

Abstract

Corrosion of reinforcement is one of the major contributors to the deterioration of reinforced concrete structures. The cause of corrosion can be due to carbonation or chloride attack. Early detection of corrosion process can prevent costly repair or structural collapse. The aim of this study was to look at the possibility of using modified fibre optic sensor to monitor the corrosion process of reinforcing steel. The corrosion process was monitored by an unclad plastic optical fibre sensor attached to a steel bar. A fibre optic spectrometer was used to detect the spectrum of the white light. The light spectrum changes in intensity as corrosion develop and progresses on the bar surface. Three samples of mortar prisms with steel bars inserted at the centre were prepared. One sample was immersed in 10% Sodium Chloride (NaCl) solution and another in 20% NaCl. The results were compared with a reference sample. The corrosion process was observed for a 20-day period. The results show that the initial value of the outgoing light from the optical fibre was 4000 counts and reduced to less than 3600 counts after 20 days. The intensity value decreases slowly as the corrosion progresses.

Pengaratan tetulang merupakan faktor utama kepada kemerosotan struktur konkrit tetulang. Pengaratan tetulang berlaku akibat pengkarbonatan atau serangan klorida. Mengesan kejadian pengaratan pada peringkat awal dapat engelakkan kerja pembaikan yang mahal atau kegagalan struktur. Tujuan kajian ini adalah untuk mengkaji kemungkinan menggunakan penderia gentian optik yang iubahsuai untuk mengesan proses pengaratan tetulang. Pengaratan tetulang dikesan menggunakan gentian optik yang dibuang salut dan diikat ke tetulang. Spektrometer gentian optik diguna untuk mengesan spektrum cahaya putih. Spektrum cahaya berubah intensitinya disebabkan produk pengaratan yang terbentuk dipermukaan bar keluli dan semakin likat dengan bertambahnya pengaratan. Untuk kajian ini, disediakan tiga bungkah sampel mortar dengan bar keluli dipasang ditengahnya. Sampel pertama direndam dalam larutan natrium klorida (NaCl) dengan kepekatan 10% dan sampel kedua dalam larutan natrium klorida dengan kepekatan 20%. Keputusan ujikaji dibandingkan dengan sampel kawalan.
Pengamatan proses pengaratan diambil selama 20 hari. Hasilnya didapati nilai awal cahaya yang keluar daripada gentian optik adalah 4000 count kemudiannya turun keparas kurang daripada 3600 count selepas 20 hari. Nilai intensiti cahaya berkurangan dengan pertambahan pengaratan

Item Type:

Journal

Keywords:

Fibre Optic Sensor, Corrosion of Reinforcement, Chloride, Durability Penderia Gentian Optik, Pengaratan Tetulang, Klorida, Ketahanlasakan

Subjects:

T Technology, Engineering

ID Code:

6505