Concrete Mix Ratio: Types and Mix Ratio Tables

The ratio of concrete mix is important in construction as it is the ratio of water to cement (w/c) that largely determines the durability and strength of the building. A w/c ratio of 0.4 means for every 100lbs of cement, 40 lbs of water must be added. Read on to find out more about the concrete mix ratio, its different types, and the ratio table for different grades of concrete.

But First Things First, What is Concrete Mix Ratio?

The ratio of concrete mix is defined as the proportion of the components that make concrete such as water, aggregates, sand, and cement. How do we determine what ratio is to be used? IS 456-2000 has designated concrete mixes into grades such as M40, M35, M30, etc. here. M refers to the mix and the digit refers to the strength of the mix after its 28th day in N/㎟.

4 Types of Concrete Mix Ratio

Check out these different types of concrete mix ratio and their grades:

1. High Strength Concrete Mix Ratio

The mix design of high-strength concrete depends on the properties of w/c ratio, sand aggregates, and cement which must be above 40 MPa. It must have a low w/c ratio to obtain high workability and proper compaction. For compressive strength values for each grade refer to the table given below.

Concrete Mix Ratio Table for High Strength Concrete

2. Designed Concrete Mix Ratio

In this type of concrete mix, the ratio of ingredients is mentioned by the producer while the performance of the concrete is mentioned by the designer. However, the minimum cement content is laid down. This type of mix ratio is economical and is a rational approach. There are several factors that determine the strength of the mix in a designed concrete such as

1. Compressive strength
2. Workability
3. Durability
4. Maximum nominal size of the aggregates
5. Grading and type of aggregates
6. Quality control

3. Nominal Concrete Mix Ratio

The specification of making concrete meant prescribed proportions of cement and coarse and fine aggregates which ensure adequate strength to the mix. These are termed nominal mixes and under normal circumstances, they have a margin of strength that is above the specified value. However, its workability varies significantly because of the variability of its ingredients. Here’s a table showing the mix ratio and compressive strength of different grades of nominal concrete:

Concrete Mix Ratio Table for Nominal Concrete

4. Standard Concrete Mix Ratio

The nominal mixes of cement and aggregate vary widely in strength and might over or under-rich the mixes. This led to the code specifying the minimum compressive strength for concrete mixes called the standard mix ratio. IS 456-2000 specified concrete mix ratio to grades M40, M35, M30, M20, M15, and M10. Check out the table below to know more!

Concrete Mix Ratio Table for Standard Concrete

Takeaway

Concrete mixing needs to meet certain proportioning and selection factors concerning its ingredients. They must satisfy the following requirements:

1. The minimum compressive strength
2. Adequate workability to achieve full compaction along with compacting equipment
3. Maximum cement content or maximum w/c ratio to achieve durability
4. Maximum cement content to avoid cracking caused by temperature changes

Concrete Mix Ratio FAQs:

1) What is the best mix ratio for concrete?

The safest concrete ratio is 4:2:1 of crushed rock, sand, and cement respectively. The ratio can be mixed on any range of scales as per the convenience of mixing concrete.

2) What is the concrete mix ratio for slabs?

To make a concrete slab, a ratio of 1:2:4 of cement, sand, and coarse aggregates are taken. The concrete mix must be placed within half an hour of mixing to make the perfect slab.

3) What is the concrete mix ratio by volume?

A basic mixture of mortar can be made using a ratio of 1:2:3 of water, cement, and sand of volume proportions. Most student activities are done using this mixture. There is another old “rule of thumb” for concrete mixes – 1:2:3 of cement, sand, and gravel by volume.

4) What is the 10-20-30-40 rule in concrete mixing?

A typical concrete mix has the following percentage of elements from which comes the 10-20-30-40 rule:

5) What is the strongest concrete ratio?

C40 concrete is the most durable and strongest mix in the civil industry. It can handle all kinds of strains such as laboratory environments, farm-based situations, and corrosion.