Frequently Asked Questions

Technical Questions

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




Question: Standard specifications for cements

Question: Requirements for durable concrete

Question: What are blended cements?

Question: How can it be determined that an admixture will serve its intended purpose?

Question: How do the code requirements get to the contractor?

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

Question: Consolidation of Concrete—Required or Not?

Question: Mixture Design and Strength Submittals

Question: Curing Cylinders for Acceptance Testing

Question: Standards for 7-day and 28-day strength test results

Question: Estimating in-place concrete strength

Question: Evaluating the properties of hardened concrete

Question: The effect of joints on the durability of concrete structures

Question: The purpose of calcium sulfate (gypsum)

Question: What is a pozzolan?

Question: What is an admixture?

Question: What is the intention of the ACI 318 Building Code?

Question: Who selects the requirements for concrete for a project?

Question: How is the required strength selected, measured, and obtained?

Question: The ultimate objective in proportioning concrete

Question: How do the requirements of placing affect the selection of proportions of aggregates and cementitious material?

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

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

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

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

Question: What nominal maximum sizes of aggregate are recommended?

Question: What water-cementitious material ratio should be used for a particular job when strength requirements are to govern?

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

Question: Temperature Limits for Mass Concrete

Question: Material Requirements for Mass Concrete

Question: Temperature Control Time

Question: How to Control Mass Concrete Temperature during Construction

Question: Predicating Temperature for Mass Concrete

Question: Minimum Dimension of a Structure

Question: Water Curing Mass Concrete Structures

Question: Air tests for nonair-entrained concrete

Question: What is mass concrete?

Question: Size of test cylinder

Question: Maximum temperature limits for hot-weather concreting

Question: How is workability measured and specified?


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