Development of Titanium Wire Sensor for Corrosion Monitoringin The Concrete Structures

1.

Headquarter, Technical Division

Rahmita Sari RAFDINALHeadquarter, Technical Division

Toshiyuki AOYAMAHeadquarter, Technical Division

Naotoshi FUKAGAWA

Introduction

similar trend. WS of 1m and 2m and the average potential of SSE in

Recently, corrosion of steel in concrete is one of the major

the installation section of the sensor, also showed similar trend.

problems with respect to the durability of reinforced concrete

3.

structures. Half-cell potential method is used as one of theConclusions

non-destructive tests to detect and inspect the corrosion ofIn this test, it was confirmed that WS shows same electricreinforcing steel in concrete by measuring the natural electric

potential value to SSE. WS of 1 m, 2 m coincides with the averagepotential of rebar. In this method, the presence of corrosion on thepotential of SSE in the installation section of the sensor. From now

rebar is judged from the difference of the electric potential value

on, based on the electric potential distribution of the rebar when abetween the reference electrodes applied on the concrete surface or

corrosion environment occurs, we will plan to set the optimum WS

embedded reference electrodes. The shift of electric potential oflength and the possibility of detecting the corrosion of the steel. We

rebar from positive value to negative value means corrosion of thealso plan to develop a method to maintain and manage WS

rebar in concrete.

measurement by remote monitoring system.

Photo-1 shows the outline of titanium wire-sensor (referred to as“WS”). The WS is a sensor made of titanium coated with an oxide
film that has a diameter of 3 mm and a length of 30 mm or more. A
length of a WS is arbitrarily settable. A WS is not expensive
compared with a reference electrode. In addition to the feature, aWS can be installed in a small space by changing the length of the

Photo-1 Titanium wire sensorsensor. There is a possibility that a single sensor can detect steel
corrosion in wide range.

SSE 2m
SSE 1mSSE

In this paper, the electric potential values of rebar measured by
the WS and reference electrodes and the possibility of corrosion

50150502,0009@200=1,800
2,100

detection by using various type length of wire sensor are reported.

150

2,000

2.

Test Overview and Results

1,000500
WR1The dimension of the specimen is 150 x 150 x 2100 mm as

18 8shown in Figure-1. The main rebar and stirrup use reinforcing steel

125WR2250

125

500

WR3250125WR4250

12 5WR 525 012 5188

Figure-1 Shape and dimensions of specimen

D13 with arrangement of longitudinal distance and transversal
distance of 75 mm and 200 mm, respectively. In this test, tosimulate the local zone corrosion situation, the electric potential of
the rebar in the central part of the specimen enforced to the minusside using a potentiostat device. The electric potential of rebar in
the axial direction of the specimen was measured with a referenceelectrode (referred to as SSE) from the concrete surface. The
measurement of SSE was at intervals of 100 mm from the concretesurface. Furthermore, the electric potential of rebar was measured
with the embedded WS electrodes with each length of 0.125 m, 1 m

Figure-2 An example of measurement resultand 2 m.

Keywords Titanium wire sensor, reference electrode, natural

An example of results is shown in Figure-2. The natural electric

potential of rebar, corrosion monitoring

potential of rebar measured by WS of 0.125 m and SSE showed

28技報

WS

SSE

SSE

100mm
0.125m-21m
WS

第 16 号（2018 年）

2m

WS

SSE

WS

SSE

-1

WS
3mm

30mm

1-2

WS

-1

SSE

WS

1m
SSE

WS
WS

WS

WS
WS

150×150×-1
2100mm
D13D13200mm

6WS

0.125m 1m 2mKey ords

SSE 2m
SSE 1m

SSE

50
15050

2,000
9@200=1,800
2,100

150

2,000

1,000

500
WR118 8125WR2250

125500

WR3250125WR4
250

12 5

WR 5
25 0

12 5

188-1

292m