Concrete Mix Design Method 1

[henri2]

For projects where ACI 318 is used, what's the most common method of concrete mix designs these days for typical concrete mixtures....statistical analysis based on field test results or trial mixtures?

 

[JAE]

I've usually seen the statistical method....where a ready mix company keeps a log of all their test results of their standard mix designs and qualifies the mix by showing the on-going strengths with their resulting variances.

 

[henri2]

JAE, thanks for responding.

In your opinion when a mix design (statistical) review is conducted should the reviewer request the ready mix company also submit copies of actual compresive strength test reports in order to verify authenticity of data used?

 

[JAE]

I've never requested it because the mix designs have always come with that sort of data....lots of 7 and 28 day breaks. Most of this data is simply other mixes used on other projects and the resulting test results.

I guess if I got a mix design and it didn't have the compressive test data I might call up for that - but our specs usually require it so it generally comes our way.

 

[henri2]

I appreciate your prompt, concise and valuable responses.

 

[Ron]

henri2...I agree with JAE that most Ready-Mix suppliers have tons of data and statistical methods are more often employed. Occasionally mix design verifications are done where the mix design is replicated and specific testing done on the design prior to its use. This is getting more rare, but the need does occur on occasion.

I require submittal of backup data when a large concrete project is contemplated or if it has some specialty application. In the submittal, I ask for compressive strength data, moving average statistical data, durability data, and aggregate source/reactivity data.