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## What Is The Best Concrete Mix Design?

The cost of concrete determines the characteristic strength, quality control, workability of mix (cost of labor) which includes the high degree of compactions. The best concrete mix design is the one which satisfies all the aspects for which it was designed.

## Strength:

The strength of 95% cube cast after 28 days of curing should be greater than the characteristic strength for which concrete has been designed.

## Workability & Placing:

As working condition changes so the properties desired from concrete also changes, the concrete which can be easily placed without segregation and with least compaction required.

## Water cement Ratio:

Water should be maximum (0.45 – 0.65).

## Durability:

The concrete must be durable enough to face harsh conditions of atmosphere for which it has been designed.

These are the main properties considered while designing concrete and the designed concrete satisfying such conditions can be called as best concrete mix design.

There are three type of mixes,

1. Nominal mixes

2. Standard mixes

3. Designed mixes

## 1. Nominal Mixes:

The mixes which have fixed cement aggregate ratio but the nominal mix concrete for a given workability varies widely In strength.

## 2. Standard Mixes:

1. It is designated by code book of **IS456:2000**

2. The minimum compressive strength have included

3. May result in under and over rich mixes.

## 3. Designed Mixes:

1. The mix proportion is designed by producer of concrete

2. The concrete is specified by the designers

3. It does not guarantee the concrete mix proportion for the prescribed performance.

**As we normally use the standard mixes which are safe and economic, as per standard code book. **

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