Paper 14394 - Presentation

Jorge Cant贸, Edgar Maya, Lorenzo M. Mart铆nez de la Escalera Carlos Lopez Andrade, Cecil Knight Jorge A. Ascencio, Lorenzo Mart铆nez G贸mez

HISTORIC FACTS: ď‚ž

As result of observations to the port authorities of Mazatlan and Salinacruz, was determined to do the evaluations of the wharves.

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A general assessment is presented showing the apparent needs of repairs and corrosion prevention for the steel reinforcement in concrete beams, slabs and pilots of the docks.

Mazatlan Dock

Salina Cruz Dock

INITIAL CONDITIONS Procedures will evaluate the status of the steel corrosion in concrete elements in particular by inspections of hotspots and identification of affected areas by performing several tests, measurements and analysis of the structure.

Documentation evaluation Documentation was collected including drawings, details, construction specifications, previous repairs, etc. The operation condition and integrity of the structures can be assessed through direct and indirect inspections.

Identification of areas with visible defects The objective was make a preliminary assessment, which provided information to determine the extent and type of studies carried out in the following stages of the examination process.

Detection of hidden corrosion defects by sounding Acoustic inspection techniques were applied, to find delamination areas, the space between the solid and loose concrete produces a particular sound that allows identification of the affected area.

Physical impact test of concrete structures to determine its resistance The resistance to force was performed with a test hammer, making physical impacts on the concrete. The mechanical strength of the steel decreases linearly with the section reduction, but also tension and fatigue resistance properties are most sensitive to corrosion.

Electric continuity verification of steel reinforcement The verification of the electrical continuity between various elements of the steel reinforcement of a structural component, provides information related to the suitability of the structure for cathodic protection. .

Polarization potential measurement on concrete structures using Cu/CuSO 4 reference cell.

The corrosion potential determination technique has proved to be a useful method to locate areas of corrosion in the structures, this method uses a Cu/CuSO 4 reference electrode , connected to a high impedance input multimeter.

Electrical resistivity evaluation of the concrete Electrical resistivity measurements are made using the method known as "Wenner" or "4 tips". The purpose of this test is to find areas in which the steel may not be passive and therefore susceptible to corrosion.

Sampling of concrete core for analysis.

Cores extraction is completed to realice, Chloride ion content and Carbonation testing

Results on Mazatlan Dock

The North Dock showed less than 20% a certain amount of delamination area

Bridge

The Main Dock showed the most amount of delamination area

Operations Platform

North Tie-up Dock

Delamination area

The south Dock showed only 10% of the total surface

South Tie-up Dock

Results on Mazatlan Dock Corrosion potential determination with a Cu/CuSO4 reference electrode North Tie-Up Dock

Potential on mV

South Tie-Up Dock

Operation platform

0 1

2

3

-50

-100

-150

50% of corrosion probability

-200

-250

-300

-350

90% of corrosion probability

Results on salina Cruz Dock There are some delamination areas in all those structures, principally in West tie-up 1 Est Tie-up Docks 1 and 2

West Tie-up Docks 1 and 2

Est Tie-up Docks 3 and 4

Delamination area

Results on salina Cruz Dock Delamination area

The Operation plataform shows several delamination areas.

Rear Docks are the structures with less damages

Rear Docks

Operation Plataform

Results on salina Cruz Dock Delamination area The Acces Bridge, and Gateways and Platforms, are the structures that shows more damages with the total of delamination surface

Access Bridge Gateways and Platforms

Results on salina Cruz Dock Corrosion potential determination with a Cu/CuSO4 reference electrode East TieUp Dock Potential 1-2 on mV

East Tie- west Tie- west Tie- Operation Up Dock Up Dock Up Dock platform 3-4 1-2 3-4

Acces Bridge

GatewaysPlatforms

0 1

2

3

4

5

6

7

-50

-100

-150

50% of corrosion probability

-200

-250

-300

90% of corrosion probability -350

Conclusions ď‚ž

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In Mazatlan, the evaluated structures are in relatively good conditions, with low risk corrosion potentials, and just a few parameters that require attention to control corrosion processes.

The structures in Salina Cruz have advanced corrosion deterioration with concrete damages which, in some areas, put at risk the operation of the installation.

Recomendations ď‚ž

ď‚ž ď‚ž

The inclusion of systems of control and protection against corrosion of these structures involves repairing the concrete as general rehabilitation strategy.

These repairs should be performed until the reinforcing steel exhibits no signs of corrosion..

For both docks systems we proposed the next possible strategies: cleaning procedures, installation of discrete and distributed zinc anodes (as the Vector Corrosion products) depending of the configuration.