Concrete |

## Factors Affecting Concrete Strength

In addition to Mixing, Pouring and Compaction, the concrete strength mainly depends on the following factors:

Factors Affecting Concrete Strength |

### (1) Water-Cement Ratio (W/C)

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To decrease in W/C will increase the strength of concrete. Normally water-cement ratio is 0.45-0.55 for normal concrete.

W/C Effects on Concrete |

### (2) Aggregate-Cement Ratio

To decrease in Aggregate-Cement Ratio increase the strength of concrete upto numerical value of 2, further decrease of Agg/Cement may cause decrease in strength on concrete.

### (3) Aggregate

The concrete strength is affected by

- Aggregate Strength
- Surface Texture
- Grading
- Maximum size of aggregate in concrete

### (4) Curing

Prolonged moist curing results in getting highest concrete strength.

## Rate Of Strength Gain by Concrete

The ACI code proposes the rate of strength gain for concrete in which type-I concrete was used at 70F° by the following Equation

fc'₍t ₎= fc'₍₂₈₎⎨t ⁄ 4+0.85t ⎬

In the above Equation

t= Time in days

fc'= Compressive strength at age t in days

## Variation in Strength of Concrete

The strength variation of finished concrete depends on

- Property of concrete component
- Methods of transportation of concrete
- Compaction of concrete
- Discripenses in the test of concrete

Compressive Test on Concrete |