These are many factors which has strong influence on strength of concrete. Of these factors are not being considering during mixing then these air entraining admixtures may have some negative impact on properties of concrete.
- The first and the main factor is the time which it took during mixing with concrete. If mixing with concrete takes longer time then as we know hydration starts at the same time when water mix up with cement. So if longer mixing time then this air entrains will not being entrained in hydrated product and then in severe condition there is not protection for that particular part.
- Amount of fine aggregates is the 2nd major factor which influences the amount air entrained. If amount of fine aggregates is higher than empty spaces in concrete will be less available and this reduces the amount of air entrained during mixing. If this happens then against frost action, protection will be less. If amount of sand is higher than in the same proportion will be the amount of air entrained, because we know sand is a cohesion free material.
- Temperature also affects the amount of air entrained in concrete. If temperature is higher than less will the amount of air entrained in fresh concrete.
- Slump value also has a positive effect on amount of air entrained. If value of slump will be higher than air content will be more as compared to normal slump value.
- If vibration is produced during mixing for better solution then this vibration removes air bubbles from fresh concrete and decreases the resistance against frost action.