Performance of PSM Maintenance Technology in the TropicalEnvironment Based on Test Piece Survey Result
㸫The first Application of Cathodic Protection in Indonesia㸫
Headquarter

Research & Development Division

Rahmita Sari RAFDINAL

Headquarter

Research & Development Division

Toshiyuki AOYAMA

Headquarter

Research & Development Division

Yuichi SHIRAMIZU

President of PT. Komponindo Betonjaya (KOBE)

1. Introduction

Hirotake KOGA

potential mapping on the concrete surface and inside theThis joint research is a pilot project between PS

concrete in this study. The specimens were exposed to a dry-Mitsubishi Construction (PSM) and the Agency fortropical climate condition as shown in Photo-1.

Research and Development, Ministry of Public Works andHousing of Republic of Indonesia (DRBE). The purpose ofthis collaborative research is to observe the effectiveness ofZinc (Zn) Cartridge which was developed by PSM as abridge repair method of sacrificial anode cathodic protection
applied and Titanium (Ti) Wire Sensor which was also
invented by us as an internal probe in chloridecontaminated concrete.
In this paper, we are reporting on experimental tests on
small reinforced concrete slabs with steel embedded inchloride-contaminated concrete to observe the effectivenessof Zn Cartridge and Ti Wire Sensor technology against steel
corrosion in Indonesia in a straightforward and simple way.

2. Research Outline
2.1 Specimen Geometry
This study prepared concrete slab specimens with 300

Figure-1 Detailed layout of concrete specimens with Zn

mm in length, 250 mm in width, and 100 mm in depth. Two

Cartridge and Ti wire sensor embedded in concrete

steel rebars with a diameter of 13 mm and one Ti WireSensor were embedded inside a concrete slab. Moreover, theZn Cartridge system contained a zinc anode with a diameterof 110 mm which was covered by backfill material, and wasapplied onto the concrete surface. Chloride ions weredeliberately added around 10 kg/m3 during mixing toaccelerate the corrosion process in concrete so that concrete
could become chloride-contaminated. Figure-1 shows thedetailed layout of concrete slab specimens.
2.2 Casting Process and Exposure Condition
After casting concrete and demolding, all specimens weresubjected to room temperature in a dry condition for 28 days.
After 28 days, the Zn Cartridge were connected to theembedded steel rebar. Silver/silver chloride electrode (SSE)

Photo-1 Specimens exposure condition

and Ti Wire Sensor were used as reference electrodes for

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3. Results and Discussion
Figure-2 shows the protective current delivered from theZn Cartridge anode to the entire rebar assembly with afunction of exposure time. It shows that the protective
current density tends to fall with time. However, eventhough the protective current flow decreased and was lessthan the minimum design limit of cathodic protection basedon BS EN ISO 12696, it could polarize the steel bar morethan 100 mV, indicating good protection.

Figure-2 Protective current flow from Zn Cartridge

Figure-3 shows the depolarization value of rebar protectedby Zn Cartridge. Depolarization test is a method to observe
the effectiveness of Zn Cartridge performance as asacrificial anode cathodic protection system. Depolarization
tests were conducted for 24 hours by disconnecting theprotective current flow from Zn Cartridge to rebar. Thepotential difference between the instant-off potential andthe potential measured 24 hours later after switching off
the Zn Cartridge anode current is called the 24-hour
potential decay, which is an important parameter used to

Figure-3 Depolarization test of rebar

evaluate the effectiveness of Cathodic Protection (CP)operation. Generally, 100 mV depolarization recorded
during a twenty-four-hour period is the most accepted
criterion for corrosion protection. Figure-3 shows the timedependency of the variation in potential decay of rebar,
satisfying the potential decay criterion, which is over 100
mV. It means Zn Cartridges demonstrated excellent
corrosion protection of the rebar.
Meanwhile, in Figure-4, two monitoring data of rebar arecompared, which were measured by SSE and the Ti Wire

Figure-4 Rest Potential of Rebar connected to ZnSensor (WS) after the depolarization test, and the data areCartridge measured with SSE and Ti Wire Sensor

called rest potential of rebar or natural potential of rebar.

Acknowledgment㻌

From the graphs, it was observed that Zn Cartridge
polarized the rebar to the noble values. It indicates that theThis pilot project was carried out as part of Joint

reinforcements in chloride-contaminated concrete are safe

Research on Bridge and Civil Structures between DRBE

from corrosion. Moreover, Ti wire sensor showed a goodand PSM. We would like to express our sincere gratitude toperformance in detecting and reading the potential of rebar

all those concerned and to KOBE as a subsidiary company

and its effectiveness was equivalent to a common electrode,of PSM in Indonesia that has already given full support toSSE. It can be concluded that the Ti Wire Sensor is durable,

this project.

stable, reliable, and economical to be used in concrete
structures in the terms of corrosion monitoring of rebar for

Key Words㸸Zn Cartridge, Ti Wire Sensor, cathodic

long-term utilization.

protection, corrosion protection, corrosion monitoring

4. Summary
From the reported work, it can be concluded that Zn
Cartridge affords excellent corrosion protection in drytropical conditions, and that Ti Wire Sensor is reliable to beused as a reference electrode for corrosion monitoring inconcrete.

Rahmita Sari

Toshiyuki

Yuichi

Hirotake

RAFDINALAOYAMASHIRAMIZU

KOGA

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