Factors affecting durability of concrete:

1. Cement Content: Quantity of cement used in concrete mix will also affects durability of concrete. If cement content used is lower than the required, then water cement ratio becomes reduced and durability is affected. If excess cement content is used, problems like drying shrinkage, alkali silica reaction may occur which finally effects the durability of concrete.

2. Aggregate Quality: Use of good quality aggregates in concrete mix will surely increase the durability of hardened concrete.

3. Water Quality: Quality of water used in concrete mixing also effects the durability of concrete. In general, potable water is recommended for making concrete.

4. Concrete Compaction: While placing concrete, it is important to compact the placed concrete without segregation. Improperly compacted concrete contain number of air voids in it which reduces the concrete strength and durability.

5. Moisture: Moisture present in the atmosphere will also affects durability of concrete structures. Efflorescence in concrete occurs due to moisture, which will converts salts into soluble solutions and when it evaporates salts become crystallized on the concrete surface. This will definitely damages the concrete structure and durability of concrete.

6. Temperature Effects: Concrete is heterogeneous material, when fresh concrete is subjected to high temperature rate of hydration gets affected and strength and durability gets reduced.

7. Carbonation: When moist concrete is exposed to atmosphere, carbon dioxide present in atmosphere reacts with concrete and reduces pH of concrete. When pH of concrete reaches below 10, reinforcement present in the concrete starts corroding. Corrosion of reinforcement causes cracks in concrete and deterioration takes place.

8. Sulfate Attack: When concrete structures are attacked by sulfates like sodium sulfate, magnesium sulfate etc. concrete disintegration happens.

9. Abrasion: Deterioration of concrete also occurs due to severe abrasion. When concrete is subjected to rapidly moving water, steel tires, floating ice continuously wearing of surface occurs and durability gets affected.

10. Alkali Aggregate reaction: Alkali aggregate reaction or alkali silica reaction, takes place between alkali content of cement and silica content of aggregates is also a major factors effecting durability of concrete.