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Handbook for Bridge Inspections - TSP2

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9.2 CONCRETE ELEMENTS<br />

206 Damage to Concrete Surface<br />

Treatment<br />

Descri ption<br />

Damage to the surface treatment of concrete bridge elements, i.c. water repellent impregnation,<br />

painting/coating, whitewashing/pore filling. Flaking, cracking, bli stering, and discoloration can be<br />

incl uded here; additionally, the surface treatment might not fu lftl lhe required in-service standards.<br />

Surface treatment applied to concrete must be able to protect the concrete from environmental<br />

impacts and improve its general appearance.<br />

Cause of Damage<br />

• Design Fault - incorrect type of surface treatment chosen.<br />

• Material Fault - incorrect type of surface treatment applied.<br />

• Construction Fault - poor pre-treatment of the surface, or the material was appl ied during damp<br />

or cold weather.<br />

• Insufficient operation/maintenance of the surface treatment.<br />

• Environmental impacts - a hosti le environment can break down the surface treatment faster than<br />

expected<br />

• In-service damage - regul ar wear and tear.<br />

Possible Materials Testing<br />

• Thickness of the surface treatment<br />

• Adhesion between the surface layer and concrete.<br />

• Impregnation depth to concrete of repellent impregnation.<br />

• Measuring chloride content and depth of carbonisation.<br />

Degree of Damage/Consequences<br />

All types of surface treatment gradually become broken down by the environmental influence. The<br />

degree of damage a ll ocated shall reflect the time remaining be<strong>for</strong>e the surface treatment requires<br />

renewal, i.e. be<strong>for</strong>e it loses its protective properties. Damage to the surface treatment wi ll affect<br />

maintenance costs and result in increased chl oride penetration and speed of development of carbonisation.<br />

These last two items can, in addition, lead to corrosion of the rein<strong>for</strong>cement and to spalling.<br />

162 <strong>Handbook</strong> <strong>for</strong> <strong>Bridge</strong> <strong>Inspections</strong>

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