Materials - Measures to prevent and reduce degradation

• Construction Principles
• Further Education (Key Stage 5)

Measures to prevent and reduce degradation

Unit 1: Construction Principles

Introduction

In most circumstances, it is possible to prevent or slow degradation by taking preventative action and performing regular maintenance.

For instance, one of the most recognisable structures in Britain, the Forth Rail Bridge near Edinburgh, is made of steel and is prone to rust. In the past, this meant having a full-time maintenance team painting the bridge. It took so long to paint that, when they reached the end, they would have to start again in a continuous cycle.

Improvements in paint technology now mean that a single coat of specialist glass flake epoxy paint protects the bridge and can be left for up 25 years without reapplication.

Introduction

The enemy of iron in which the Eiffel Tower (also known as 'The Iron Lady') is completely constructed from, is corrosion, caused by water and air that gradually oxidise iron exposed to open air. 

It has exceeded its useful design life of 20 years (the structure was built in 1889!)  thanks to a rigorous maintenance program that is mainly based on the replacement of corroded parts and the use of a repainting scheme, with a frequency of 7 years, as a method of prevention and control of atmospheric corrosion.

The layer of paint that protects the metal of the Tower is very effective, but it must be periodically replaced. 

Introduction

For its inauguration in 1889, the Eiffel Tower was painted dark red. Then from 1892 it was painted ocher, followed by yellow from 1899, mustard up until 1954 and garnet until 1968. Since then, it has been painted brown (bronze). 

Since its construction, it has been manually covered with brushes more than 19 times .

25 painters use 1,500 brushes and rollers to apply 60 tons of anti-corrosive coating during an 18-month renovation period. Today, the cost of these repainting works costs approximately €4 million.

Steel

Measures to prevent and reduce degradation

Steel degrades through corrosion, select the correct prevention/remediation techniques

Painting to exclude moisture.

Consider replacement with stainless steel.

Maintain good ventilation.

Galvanising

Timber

Measures to prevent and reduce degradation

Timber degrades through wet and dry rot, select the correct prevention/remediation techniques

Painting to exclude moisture.

Address any signs of chronic damp

Maintain good ventilation.

Apply anti-fungal timber treatment.

Remove and replace infected timber.

Apply insecticide timber treatment.

Timber degrades through insect attack, select the correct prevention/remediation techniques

Painting to exclude moisture.

Address any signs of chronic damp

Maintain good ventilation.

Remove and replace severely weakened timber.

Apply insecticide timber treatment.

Stonework

Measures to prevent and reduce degradation

Stonework degrades through acid rain, select the correct prevention/remediation techniques

Painting to exclude moisture.

Address any signs of chronic damp

Maintain good ventilation.

Specialist surface treatment.

Remove and replace severely damaged stonework.

Concrete

Measures to prevent and reduce degradation

Concrete degrades through sulphate attack, select the correct prevention/remediation techniques

Painting to exclude moisture.

Address any signs of chronic damp

Maintain good ventilation.

Use gypsum (calcium sulphate)-free aggregates.

Use sulphate-resistant cement.

Polymer

Measures to prevent and reduce degradation

Polymers degrade through exposure to UV, select the correct prevention/remediation techniques

Painting to exclude moisture.

Address any signs of chronic damp

Maintain good ventilation.

Use polymers with a UV-inhibiting additive.

Did you enjoy today's lesson?

😒🙁😐🙂😃

What did you like most? What needs improving?