Factors affecting properties of hardened concrete:
1. Type and quality of materials used: If type and quality of materials used for concrete i.e. cement, sand, aggregate and water is not as per IS recommendations, then the properties of hardened concrete like strength, durability will affect drastically. Reactive aggregates reduce fire resistance and acidic/alkaline water gives cracks in concrete. Lesser grade of cement reduces strength and durability of hardened concrete.
2. Mix proportion of materials: The badly mix proportion of good quality materials will result in reduced segregation and bleeding, which finally shows reduced workability and strength of concrete. Improper mix i.e. random water cement ratio shows harshness in concrete, which finally results in unfinished surface of hardened concrete.
3. Methods of concreting operations: If the concreting operations like batching, mixing, transportation are not completed in standard manner, then one cannot ensure sufficient strength and durability of concrete in hardened stage. Also lesser compaction results in honeycombing, which shows lack of impermeabilty in concrete.
4. Workmanship: This is another important factor on which all the properties of hardened concrete depend. If the supervisors, labours, masons etc are not working properly, then the bad workmanship result in various defects in hardened concrete in terms of reduced strength, more chances of creep etc.
5. Weather conditions: The atmospheric variation also affects the properties of hardened concrete. The high temperature results in expansion cracks and reduced temperature gives rise to shrinkage cracks. Alternate drying and wetting of concrete in monsoon season may shows creep in concrete. The sudden change in weather conditions reduces strength and durability of hardened concrete.