In this article we will discuss about difference between nominal mix and design mix of concrete. In the nominal mix of concrete, mixing is done at the construction site while design mix is prepared in ready mix concrete plants.
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What are the Differences Between Nominal Mix and Design Mix?
| Nominal Mix | Design Mix |
|---|---|
| When concrete is made using any standard proportions of concrete components, it is known as a nominal concrete mix. | This is the process of selecting suitable concrete components and determining their relative proportions with the aim of producing concrete with a specified minimum strength and durability as economically as possible. |
| A nominal mix is a mix that takes into account the strength and cost of concrete and all volume ratios of concrete with different strengths. | The design mix is a mix with constant concrete strength and a weight ratio for all mix ratios. You can reduce tangible costs. |
| Used for ordinary concrete with a concrete grade not exceeding M20. | Concrete with a focus on performance. Assuming higher quality concrete. |
| Water to cement ratio based on durability standards, experience and field tests. | Water-to-cement ratio based on concrete quality and 28-day concrete compressive strength and concrete durability. |
| Moisture content can be changed by slump value (field-based test) Trapped air volume is not taken into account. | Moisture content can be changed considering the compression modulus value (laboratory test) The entrapped air content is taken into account according to the aggregate nominal size. |
| The concept of trial mixing is mentioned. | It doesn’t really care about trial mixes. |
What is Nominal Mix?
Used for less critical and simpler concrete work. In this type of mixture all ingredients are prescribed and their proportions are indicated.
Therefore, there is no room for designer deviations. Nominal concrete mix can be used for concrete of M-20 and below.
What is Design Mix?
This is a performance-based blend that leaves the choice of ingredients and proportions to the designer.
The user simply specifies requirements for concrete in its fresh and hardened state. The requirements for ready-mixed concrete are workability and processing properties, whereas the requirements for hardened concrete are primarily compressive strength and durability.