The primary source and causes of deterioration and decay in structures and buildings can be listed as follows:

1. Effect of climate

• Wetter winter and sudden heavy downpours make it even more important to direct rainwater and melt water away from house , paved area, road etc.

• Freezing and thawing

• The most sever climate attack on concrete occurs, when concrete containing moisture is subjected to cycle of freezing and thawing.

• The capillary pores in cement paste are of such a size that water is then will freeze when temperature below $0^oc$.

• The repeatative cycle of freezing and thawing have cumulative effect.

Preventive measure

• Use of low water cement ratio

• Use of durable aggregate

2. Moisture

• Penetration of the external fabric of cladding, or through ground floor constructions giving to dampness which may create a suitable condition for fungi growth and attack.
• Excessive moisture in the internal atmosphere which may lead to excessive condensation and corrosion.
• Irrigation
• Faculty Plumbing.

3. Temperature

Change in temperature cause a corresponding change in the volume of concrete. Basically there are three temperature changes phenomenon that may cause damage to concrete

a. First there are temperature change generally internally by the heat of hydration of cement

b. Second there are changes generally by variation in climate condition.

c. Third there are temperature change generated from external source- fire damage.

Internally generated temperature difference

• Crack form internal resistance will be shallow and isolated.

• Crack form internal resistance will extend full section.

Prevention measure

• Using low heat cement .
• Placing concrete at minimum practical temperature.

Externally generated temperature difference

• In this temperature difference leading to the concrete volume change is cause by externally factors usually changing climate condition.
• Spalling at expansion joint

Prevention measure

Use contraction and expansion joint.

4. Chemical

Interaction of certain cleaning agents with materials and/or components causing disintegration, softening or discoloration.

• Promoting Corrosion

• Interaction of certain dissimilar materials in close contact with one another in a corrosion environment.

5. Erosion and loading on serviceability and durability

• Erosion refer to wearing away by the surface by friction.

• The concrete use in the road, floor, pavement and the concrete use in hydraulic structure should exhibit resistance again abrasion erosion and cavitation.

• The shape and surface texture of aggregate play and important part in abrasion and erosion resistance of concrete.
• Use of steel fibre and polymer based system in concrete matrix improve abrasion resistance of concrete.

6. Human

• Failure to clean and carry out routine maintenance
• Ignorance of the causes of deterioration and decay
• Poor planning for proper maintenance
• Failure to promote awareness of maintenance needs by all who use the buildings.
• Adopting a negative attitude of waiting until emergency measures are required.

7. Atmospheric

Reaction of the structure, external fabric, finishes and cladding to the atmospheric elements such as:

• Wind
• Rain
• Sun
• Frost and snow for cold weather
• Pollution in the atmosphere

Reaction of the building to the penetration of the above atmospheric elements.

8. Structural

• Reaction of the structural elements to settlement, moisture, shrinkage and thermal movements.
• Reaction of the structural elements to the change of loading patterns.
• Natural aging of the structural elements
• Reaction to the corrosive elements in the atmosphere
• Deterioration due to inadequate inspecting and maintenance

9. Fire

• Aftermath of a fire many possibilities may occur.
• Need for replacement of materials directly effected by the fire
• Damage can be done by the fire fighters in their efforts to control the fire
• Water used during the fire fighting can not only damage but also set up deteriorating in materials not directly involved.
• The heat and the combination of heat and water can lead to the swelling, distortion, spilling and cracking of nearby materials and components.

10. Faulty Design

• Poor detailing at the design stage including:
• Insufficient allowance for expansion or contraction
• Absence of weathering - Incorrectly placed damp – proof courses
• Poor jointing between different materials or components
• Poor specification
• Lack of adequate consideration of future maintenance problems
• Inadequate provisions for access to carry out maintenance activities.

11. Faulty Construction

• Lack of supervision during construction period
• Failure to understand or follow exactly the specification and/or drawings
• Failure to replace defective work
• Failure of Designer/Architect/or Engineer monitor works in progress
• Lack of skilled labor
• Over emphasis or need for quantity rather than quality
• Failure to fully appreciate the consequences of shady or poor and/or materials

12. Faulty Materials

Failure of client, builder, designer or architect to reject sub-standard materials.

• In adequate inspection of materials by supplier or receiver
• Inadequate storage facilities on site
• Inadequate/or inconsistent mixing of materials on site

Faulty Components

Similar condition to those given above for faulty material can lead to deterioration and decay of the fabric, services or finishes of the structure of building.

13. Faulty System

• Inadequate knowledge on the part of the designer or architect leading to an unsatisfactory design, detail of system.
• Inability of the installer to follow the specification and/or drawings
• Inadequate testing of the system before commissioned
• Failure of owner to follow maintenance instructions provided by manufacturer or designer.
• Inability of the owner to operate the system as instructed.

14. Cleaning

• Failure to carry out routing cleaning operations
• Use of incorrect cleaning materials and/or techniques
• Inadequate supervision of cleaners to ensure that cleaning is thorough
• Failure of owner to tenant to provide sufficient space, enough time or the correct equipment and materials for cleaning operations
• Failure to employ specialists for cleaning special fittings and equipment.