GalvaPulsefor

ELECTRICAL RESIST ANCE, HALF-CELL POTENTIALS ,

&

CORROSION RATE

Features

• Estimation of the reinforcement corrosion rate in less than 10 seconds.

• Reliable evaluation of reinforcement corrosion in anaerobic concrete

environment.• Half-cell potential along wi th the electrical resistance of the cover lay er.

• Lightweight electrode, handheld computer and easy-to-operate software.

• Durable guard ring system for focusing the current field to the reinforcement.

• Measurement on uneven and rough surfaces.

• Easy data export to Windows PCs for plotting of data.

Tel.: (21)3154-3250 / 3154-3251 Fax.: (21) 3154-3259

Rogertec

Rua Correia de Araújo, 131Barra da Tijuca - Rio de JaneiroCep 22611-060 - RJ - Brasil

ROGERTEC®

RO

GER

TEC

GalvaPulse '

System Overview

Germann Instruments’ GalvaPulse utilizes the

galvanostatic pulse method, which is the latest

technique for assessing the risk of corrosion to

the reinforcement in concrete structures.Trad itional corrosion mapping can lead to

misinterpretation of potential readings when

encountering an extremely wet, dense or

polymer-modified concrete that has limited

access to oxygen.The galvanostatic pulse method induces a short

duration anodic current pulse into the reinforcement galvaostatically via a measuring

cell that consists of three elements: a counter electrode, a reference electrode and a

guard ring (See next page).

The applied current is usually in the range of 5 to 400µA. The typical duration of thecurrent pulse is up to 10 seconds. The reference electrode records the resulting

change in electro-chemical potential of the reinforcement as a function of polarization

time.

As with other corrosion mapping systems, the concrete cover must be exposed to

determine that each length of reinf o rcement be intact electricall y. For estimating thecorrosion rate, the rebar size needs to be known.

Estimating Corrosion Rate

By utilizing the ohmic resistance (electricalresistance), the DC polarization resistance

over time, and the applied current, the

corrosion current can be estimated with

the Stern Geary equation.

When the diameter of the corrodingreinforcement and its exposed length are

known, the confined reinforcement area

can be calculated.

Faraday’s law of electrical equivalence

states that 1mA/cm2 corresponds to a cross section loss of approximately 10mm/year . The corrosion rate can be estimated b y the fo llowing equation.

Corrosion Rate ~ 10.Icorr

/A

The corrosion rate is in µm/year .I

corris the corrosion current in µA.

“A” is the confined area of the reinfo rcement in cm 2.

Tel.: (21)3154-3250 / 3154-3251 Fax.: (21)3154-3259

Rogertec

Rua Correia de Araújo,131Barra da Tijuca - Rio de JaneiroCep 22611-060 - RJ - Brasil

ROGERTEC®

RO

GER

TEC

GalvaPulse '

Three-element measuring cell

The design of the three-element

measuring cell is due to the nature of real

world RC structures. The GalvaPulse’ scounter electrode is much smaller than

that of the reinforcement, resulting in the

electrical signal tending to vanish with

increasing cover to the reinforcement.

As a result, the measured effectivepolarization resistance cannot be connot

be converted to a corrosion rate unless a

second concentric counter electrode is used. This guard ring confines the applied

current to an area equivalent to the first counter electrode.

PSION Workabout datalogger

A PSION Workabout handheld computer recor ds the data, which

can be downloaded to a Windows-based software for print out on

an IBM-compatible PC. The readings can be exported to MicrosoftExcel. The suplied “GalvaPulse Data Veiwing and Reporting

Program” can graphically display the potentials, electrical resistance

and corrosion rate in 2D or 3D charts.

A pulse generator to supply the applied current is mounted on the

back of the PSION.To check the perf ormance of the GalvaPulse, a

concrete sample cast with a corroding rebar and

a stainless steel bar is supplied with the kit.

Data Viewing

Graphics

Corrosion activity

represent in coloras

2D o r 3D

Tel.: (21)3154-3250 / 3154-3251 Fax.: (21)3154-3259

Rogertec

Rua Correia de Araújo,131Barra da Tijuca - Rio de JaneiroCep 22611-060 - RJ - Brasil

ROGERTEC®

RO

GER

TEC

GalvaPulse '

GP-5000 GalvaPulse Kit contains:

• PSION Workabout computer/dataloggerwith installed GalvaPulse software and

at tached pulse gener ator .

• Measuring cell with 6 meter cable.

• Sponge for measuring cell.

• Reinfo rcement locator .• Reinfo rcement conductivity meter .

• Cable for data transfer to PC.

• Measuring cable, banana plugs.

• Two adjustable clamping pliers.

• Four spare batteries for PSION.• Bottle of tap water .

• 12mm and 18mm drill bits.

• Emery cloth.

• Two reinf o rcement adaptors.

• 10mm Al len key.• Hammer .

• Measuring tape.

• Chalk.

• CD-ROM with GalvaPulse Data Viewing

and Reporting Program for Windows PCManuals.

• Foam-lined carrying case.

Supplied sperately with kit:

• Cable drum with 15 meters of cable.• Concrete sample with a corroding

rebar and a stainless steel rebar .

Dimensions of sample may vary

with kit.

Tel.: (21)3154-3250 / 3154-3251 Fax.: (21)3154-3259

Rogertec

Rua Correia de Araújo,131Barra da Tijuca - Rio de JaneiroCep 22611-060 - RJ - Brasil

ROGERTEC®

RO

GER

TEC