Concrete Mix Design Just Got Easier

concrete ready mix truck
concrete ready mix truck

A concrete mix is a combination of five major elements in various proportions: cement, water, coarse aggregates, fine aggregates (i.e. sand), and air. Additional elements such as pozzolanic materials and chemical admixtures can also be incorporated into the mix to give it certain desirable properties. While a ready mix concrete design is a process of selecting ingredients for a concrete mixture and deciding on their proportions. When designing a mix, you should always consider the desired strength, durability, and workability of the concrete for the project in question.

Get Your First SmartRock Concrete Sensor for FREE

Giatec SR demo kit_
Giatec SR demo kit_

Needless to say, all ready-mix producers strive to find the perfect proportions of these ingredients in order to optimize their concrete mixes and give their concrete strength, durability, workability, and other desirable properties. It’s important to optimize concrete to ensure the lowest cost while maintaining the highest strength of your mixture. This is far from easy, as every addition or subtraction to the concrete mix entails adjustments to the components, making the process very complicated and inefficient. The solution is Giatec’s Concrete Hub app.

Concrete Mix Design

Concrete mix design is often mistakenly referred to as “cement mix design.” However, cement is simply one of the ingredients of concrete. It is a binding substance that allows concrete to set, harden, and adhere to other materials. Therefore, it cannot and should not be used interchangeably with concrete mix design.

Concrete Mix Ingredients- Graph

Calculating Concrete Mixes

Giatec’s free Concrete Hub app now features a new mix tool that allows you to design your concrete mixture quickly and easily. No need to have the ACI standard on hand–the application provides all guidelines and performs all calculations for you.

How to Design a Ready Mix Concrete

In general, concrete mixes must follow the guidelines (ACI Committee, 2009). A ready mix concrete can be designed using the tables and calculations provided in the standard.

All concrete mixes possess unique properties, the design process can be time-consuming and challenging. The Concrete Hub app, however, solves these challenges associated with creating a unique ready mix concrete.

Concrete Hub’s Concrete Mix Design Tool

The Concrete Hub app now provides an easy, fast, and free way to perform a preliminary mix design. The app also features an add-on allowing you to create proportions for your  ready mix concrete design using either the absolute volume or weight method.

The application performs all the calculations in either SI or Imperial units according to the ACI 211.1-91 standard and provides guidelines from the standard at each step via the Help icon. Once your ready mix concrete design is complete, the app generates a summary file that can be easily shared.

Concrete Mix Design Just Got Better

Learn About Concrete Maturity Sensors

Ready Mix Concrete Design Made Easy

Easily monitor concrete strength with SmartRock! Learn more here!

Step 1: Slump Flow

The first step of the application requires you to define the maximum and minimum slump for the fresh mix properties.

  • If the flow dimensions are unknown, you can use the Help icon to define the type of element that outputs the associated slump requirements.
  • The concrete slump represents the flowability/workability of a concrete mix. For example, a higher slump allows for better placement in congested reinforced elements.

*The Help guideline is based on Table 6.3.1 (Table A1.5.3.1) of the ACI standard.

Table 6.3.1 - Recommended slumps for various types of construction
Source: Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete (ACI 211.1-91)

Step 2: Aggregate Size

You will also need to define the aggregate size required for the mix design.

  • In general, the maximal dimension of the coarse aggregate is governed by the limitations of the structure cross-section and reinforcement design.
  • Increasing the aggregate size is usually more economical as it reduces the amount of cement per unit of volume; however, it may affect the workability of the mix. In contrast, reducing the maximal size of the coarse aggregate allows your ready mix concrete to reach higher strength at an equivalent water-cement ratio.

*The Help icon available on this page proposes different aggregate sizes based on the limitation of Tables 6.3.3 (A1.5.3.3)

Table 6.3.3 - Approximate mixing water and air content requirements for different slumps and nominal maximum sizes of aggregates
Source: Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete (ACI 211.1-91)

Step 3: Mixing Water and Air Content

Now you get the first estimation of the amount of water required to obtain the appropriate workability for your mix, based on the slump flow and aggregate size.

  • The Concrete Hub app also suggests the amount of entrapped air required for non-air-entrained or air-entrained concrete.
  • The entrapped air is an important parameter when the concrete structure is exposed to freezing or de-icing salts. In such conditions, increased air content will increase concrete durability because it allows the water to expand in the entrapped air when it freezes. This reduces the internal pressure caused by the formation of ice.
  • The Help menu in this step automatically calculates the water weight and the amount of entrapped air required based on the recommended values of ACI committee Tables 6.3.3/ A1.5.3.3.

Air-Entrained Concrete - Concrete Mix Design
Air-Entrained Concrete, Photo credit: Portland Cement Association (PCA)

Step 4: Concrete Strength and Water/Cement Ratio

The water/cement ratio is the most important parameter of the concrete mix design; it governs the strength, durability, and workability of the concrete mix. Here, you will need to enter the required compressive strength and associated water/cement ratio.

  • For example, reducing the water/cement ratio will increase the strength of the concrete and provide better durability. However, decreasing the water/cement ratio can also significantly reduce the workability of the concrete. In these cases, one possible solution is adding water reducer to the mix (see Step 7).
  • Using the Help option, you can select the desired compressive strength and receive the corresponding water/cement ratio, calculated based on Table 6.3.4(a) A1.5.3.4(a)). In addition, you will receive guidelines for the maximum permissible water/cement ratio based on the structure exposition (Table 6.3.4(b)/ A1.5.3.4(b)).
  • Using your input data, the app will calculate the amount of cement required. Note that the amount of cement can be reduced by introducing pozzolanic materials to the mix.

Table 6.3.4(a) - Relationship between water-cement or water-cementitious materials ratio and compressive strength of concrete
Source: Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete (ACI 211.1-91)
Table 6.3.4(b) - Maximum permissible water-cement or water-cementitious materials ratios for concrete In severe exposures*
Source: Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete (ACI 211.1-91)

Step 4.1: Pozzolanic Materials

Dry Fly Ash Powder - Concrete Mix Design
Fly Ash. Photo Credit: IndiaMart

  • This step also gives you the option of including pozzolanic materials such as fly ash, silica fumes, or slag in the mix.
  • Using pozzolanic material to replace a portion of the cement is more ecological and economical. Typically, it slows down the curing mechanism and provides enhanced properties to the concrete.
  • You can select the preferred method of calculation. Based on the specific gravity of the pozzolanic material, a new adjusted water/cementitious material ratio, amount of pozzolanic material, and adjusted cement weight will be calculated.

Step 5: Coarse Aggregate

You are now required to define the unit weight of coarse aggregate, finesse modulus, and volume of coarse aggregate per volume of concrete.

  • The application will then output the quantity of coarse aggregate required.
  • The Help option lets you select the coarse aggregate size and modulus of the finesse of fine aggregates; it then outputs the volume of oven-dry-rodded coarse aggregate.
  • The calculation is based on values from Table 6.3.6/ A1.5.3.6. This table is based on the workability of the concrete.

Table 6.3.6 - Volume of coarse aggregate per unit of volume of concrete
Source: Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete (ACI 211.1-91)

Step 6: Fine Aggregate

The amount of fine aggregate is calculated differently depending on the method of calculation (per weight or per volume) you choose.

  • The volume method calculates the amount of fine aggregate based on 1 yd3 (1m3) of concrete while the weight method performs the calculation based on an estimation of concrete weight.
  • Depending on the type of concrete (non-air-entrained or air-entrained), the first estimate of concrete weight can be calculated using ACI Table 6.3.7.1/ A1.5.3.7.1, which is provided in the Help section of Step 6.

You now obtained; the calculated quantity of fine aggregate required for the proposed concrete mix needed for the final calculations.

Table 6.3.7.1 - First estimate of weight of fresh concrete
Source: Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete (ACI 211.1-91)

Step 7: Adjustment for Moisture in Aggregates

The last step in the calculations adjusts the amount of water in the mix design based on the input of the moisture content and degree of moisture absorption of coarse and fine aggregates.

  • It is important to consider the amount of water the aggregates give to the mix and retrieve from the mix because this causes variation in the water/cement ratio.
  • The Concrete Hub app computes the new quantity of water, coarse aggregate, and fine aggregates based on the input values.
  • The amount of water can further be reduced with chemical admixtures like water reducer.

Step 7.1: Chemical Admixtures

This step gives you the option of incorporating water reducer, air-entrained admixtures, or other chemical admixtures to the mix composition.

  • Adding a water reducer allows you to keep a constant water/cement ratio for a smaller cement ratio with compromising the strength and increasing the workability.
  • Air-entrained admixtures can be very useful when trying to increase the durability and workability of a concrete mix.

Step 8: Summary Design

Finally, the last part of the process is obtaining your summary report of your findings.

  • You will be asked to enter the required volume of your concrete batch.
  • The app will then display the details of your concrete mix and the quantity of each material required for the specified volume of concrete.
  • You can then share the summary report of the mix calculation with your team via email.

The concrete hub app provides a free, fast, and easy process to create a concrete mix design. Simple and efficient, the app performs all calculations and then prepares a summary report of your mixture

Ready to get started? Download the Concrete Hub app on:

Sources:
https://www.concrete.org/
*Editor’s Note: This post was originally published in May 2018 and has been updated for accuracy and comprehensiveness.

8 Responses

  1. It’s good to know that you need to define the aggregate design before you mix your concrete. My brother wants to get some work done on his yard with exposed aggregate concrete. I’ll pass this information along to him so that he can ensure that everything is done in the right order.

    1. Hi there, unfortunately, this is a research article written for educational purposes and and is not in our area of expertise. We appreciate your interest in Giatec and are sorry we are not able to help you in finding further information regarding concrete mix design.

  2. I really like your information about concrete mix design. My husband and I are trying to find some concrete mix to make a patio. We’ll start looking into what goes into a concrete mix before buying one.

Leave a Reply

Your email address will not be published.

Related Articles

Top 11 Green Ready-Mix Concrete Producers in North America 

Sustainability and green movements have been quickly taking over industries, and construction is no different. Every year, 20 billion tons (10 billion cubic yards) of concrete are produced globally. This makes it the second most consumed product on earth, after water. Cement is not only the most expensive ingredient in a concrete mix, but its production is also responsible for 8% of global CO2 emissions. Get Your First SmartRock Concrete Sensor for FREE Free Demo Kit Ready-mix concrete, concrete that is batched for delivery from a…

New Giatec 360 Updates – Part 2: Graph Customization Tools

This article will continue on the topic discussed in Part 1, be sure to check it out! Get Your First SmartRock Concrete Sensor for FREE Free Demo Kit DisplayThe max and min temperature limits can be assigned to a sensor using the Parameter Thresholds function on both the app and the web platform of Giatec 360. When assigned, these limits are represented in the form of fine lines in red (max limit) and blue (min limit) color. Using the 360 dashboard, a user can choose if they…

New Giatec 360 Updates – Part 1: Temperature, Strength, and Maturity Charts

As part of Giatec’s continued efforts and goal to meet customer requirements and expectations, progressive changes are being made to the system to better comply with updating needs. Working with clients on a global scale, we strive to provide a streamlined platform that is one place for all. With the feedback collected from our valued customers several updates and transitions have been made to the Giatec 360 program, especially the ‘Charts’. To learn what the updated site has to offer and how beneficial this can be…

Missed This Year's Net Zero Construction Conference? We've Got You Covered!

Register for Full Access to All the Recorded Sessions Until April 30th

Claim Your Free Demo Kit

Get Your First SmartRock Concrete Sensor for FREE

Get Real-Time Data with SmartRock®

See how it works today

We use cookies to provide you with a better experience, analyze site traffic and assist in our marketing efforts. By continuing to use this website, you consent to the use of cookies in accordance with our Privacy Policy Page.