Types of Concrete Mix Ratio

When making a mix of concrete, the term concrete mixer ratio – also known as concrete mixing ratio – refers to the quantities of components used in making the concrete mix.

The concrete mixing ratio is determined by the type of work. However, local building codes specify nominal and standard concrete mixer ratios for different types of works.

It is important to note that the selection of a type of concrete mix depends on the requirements of strength and the nature of construction work.

Here are the different types of mix of concrete ratio.

Types of Concrete Mixer Ratio

1. Nominal Concrete Mix Ratio

In the nominal mix of concrete, the proportions of components – cement and aggregates – are prescribed in the standard specifications.

The volumes are specified in the ratio of cement to aggregate to achieve a certain level of strength.

The proportions of materials for nominal concrete mixes are 1:2:4 for M15, 1:1.5:3 for M20, etc., and are adopted without any scientific base, only based on past empirical studies.

As such, a nominal mix is ideal for very small concrete works.

2. Standard Concrete Mix Ratio

Nominal mixes of cement-to-aggregate ratios are not accurate. They vary widely in strength and can result in below- or above-standard mixes.

To avoid these variations, a minimum compressive strength is included in many specifications – resulting in what is commonly known as standard concrete mixes.

The IS 456-2000 classifies mixes into seven grades: M10, M15, M20, M25, M30, M35, and M40 – where the letter M stands for ‘mix’, while the number refers to the specified 28-day cube strength of mix in N/mm2.

Concrete mix of grades M10, M15, M20, and M25 closely match the nominal mix proportions of 1:3:6, 1:2:4, 1:1.5:3, and 1:1:2, respectively.

3. Design Mix of Concrete Ratio

In this mix of concrete, the performance of concrete is stated by the designer but the mix ratios are determined by the producer of concrete.

However, the minimum cement content can be laid down.

In design mix concrete, ratios of components are accurately determined to achieve a mix with the desired strength. It is also made according to the required properties of fresh concrete.

The design mix of concrete is the most appropriate tactic to select mix proportions. It results in the most economical production of concrete with suitable properties.

Nevertheless, the design mix of concrete does not guarantee the correct mix ratios for the prescribed performance.

For concrete without tough performance necessities, nominal or standard mixes may be used – but only for small projects whose 28-day strength of concrete does not exceed 30 N/mm2.

Below is a table of various types of concrete mixes and their strength.

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