Frequently Asked Questions

In This Section

Other Sources for Answers

Search other resources on the ACI website for answers to technical questions

Technical Questions

ACI Committees, Membership, and Staff have answered common questions on a variety of concrete related topics.



Found 34 FAQs.

Question: How does the relative amount of each ingredient used in concrete influence the properties of con...

Question: Consolidation of concrete—required or not?

Question: The effect of entrained air on the workability of concrete

Question: What is involved in the process of mixture proportioning?

Question: How do the requirements of placing affect the selection of proportions of aggregates and cementi...

Question: Mixture design and strength submittals

Question: What does ACI recommend regarding water-cement (w/c) ratios or admixtures to improve workability...

Question: What is the basis of proportioning to ensure concrete of the desired weather resistance?

Question: The effect of aggregate shape on concrete strength

Question: Air tests for non-air-entrained concrete

Question: The effect of aggregate grading on concrete strength

Question: Are the proportions of ingredients inter-related to produce concrete of a given workability?

Question: The effect of changes in proportions of the fine and coarse aggregate or the quantity of cementi...

Question: How is the selection of mixture proportions affected by the materials to be used and the placing...

Question: What tests are necessary or desirable in making a series of trial mixtures to arrive at a suitab...

Question: The basic approach used in the ACI mixture proportioning method

Question: The ultimate objective in proportioning concrete

Question: Why is the workability of concrete important?

Question: How is workability measured and specified?

Question: Air content common limits

Question: What consideration should be given to water that may be lost from concrete between the time it l...

Question: Can trial mixtures be made with full-size batches at the start of a job?

Question: What is the difference between corrected and uncorrected weight in a concrete mix design?

Question: Why is combined aggregate grading used?

Question: What water-cementitious material ratio should be used for a particular job when strength require...

Question: What allowance should be made for strengths where air-entrained concrete is to be used?

Question: How should the aggregates and other ingredients be measured to obtain uniformity in proportions?

Question: If time is not available for preliminary tests, how can the desired strengths be ensured?

Question: What range in slump is recommended for various types of construction?

Question: Can you use any source of water as mixing water?

Question: Aggregate blending

Question: What correction should be made for absorbed water and surface water carried by the aggregates?

Question: How is the water-cementitious material ratio (w/cm) expressed?

Question: Are there data relating w/cm to flexural strength that are as reliable as those for compressive ...