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Founded in 1904 and headquartered in Farmington Hills, Michigan, USA, the American Concrete Institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensus-based standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete design, construction, and materials, who share a commitment to pursuing the best use of concrete.
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Home > Tools > Frequently Asked Questions
Question: Size of test cylinder
Question: Alternative methods for measuring crack width
Question: Curing Cylinders for Acceptance Testing
Question: Why are many non-destructive tests used as “estimators” of concrete strength?
Question: Improving the abrasion resistance of concrete
Question: Maximum temperature limits for hot-weather concreting
Question: Estimating in-place concrete strength
Question: Low-strength cylinder test results
Question: How should samples of freshly mixed concrete be taken in the field to provide information on con...
Question: ACI code for evaluating existing buildings prior to repair
Question: Resistance to cycles of freezing and thawing
Question: The effect of maximum size of aggregate on concrete strength
Question: How is the required strength selected, measured, and obtained?
Question: What test conditions affect the results of compressive strength tests of concrete?
Question: Strength of concrete
Question: The effect of air content on concrete strength
Question: The effect of changes in proportions of the fine and coarse aggregate or the quantity of cementi...
Question: How is the air content of freshly mixed concrete determined?
Question: Mixture design and strength submittals
Question: Air tests for non-air-entrained concrete
Question: Using core strength to calculate compressive strength of an existing structure
Question: How are properties of concrete in the structure measured?
Question: How is the shrinkage of concrete determined?
Question: How is the temperature of concrete measured?
Question: Using cube tests in lieu of cylinder tests
Question: Definition of portland cement
Question: Consistency, plastic consistency, and workability
Question: Factors governing the strength of concrete
Question: How can durable aggregates be ensured?
Question: Why is the workability of concrete important?
Question: How is workability measured and specified?
Question: What test is available to evaluate the behavior of no-slump concrete as it is vibrated?
Question: Is the cutting of cores or other shaped specimens directly from a completed structure ever used ...
Question: Measurement of setting time
Question: How can it be determined that an admixture will serve its intended purpose?
Question: What methods of capping are recommended for compression specimens?
Question: Important requirements of a concrete aggregate
Question: Are there any tests that may be made directly on the structure to determine if the concrete has ...
Question: What are rebound, penetration resistance, and pullout tests?
Question: Definition of setting time
Question: Is the slump test of value as a measure of consistency or workability?
Question: How is the abrasion resistance of concrete determined?
Question: Standards for 7-day and 28-day strength test results
Question: How is the permeability of concrete determined?
Question: Rebound hammer and in-place strength testing
Question: What procedure should be followed for standard curing of specimens for strength tests?
Question: When is the slump test useful in detecting changes in the concrete?
Question: The cause of false set
Question: What tests are necessary or desirable in making a series of trial mixtures to arrive at a suitab...
Question: Why is the slump test not an absolute measure of consistency or workability?
Question: Is density a good indicator of air content?
Question: Precautions against sulfate attack
Question: How is the air content of hardened concrete determined?
Question: Protecting against excessive expansion due to alkali-aggregate reaction (AAR)
Question: The most important single factor affecting compressive strength
Question: If time is not available for preliminary tests, how can the desired strengths be ensured?
Question: How can the surface or free water carried by the aggregates be determined?
Question: What are the ultrasonic pulse velocity and the pulse echo tests?
Question: How is strength estimated by the maturity method?
Question: Can trial mixtures be made with full-size batches at the start of a job?
Question: When does the slump test provide a useful indication of workability?
Question: Is storing the specimens on the structure always a satisfactory procedure for estimating in-plac...
Question: Curing Test Specimen at High Temperatures
Question: How is the resistance to alkali-aggregate reaction (AAR) determined?
Question: False and flash set
Question: How is the water-cementitious material ratio (w/cm) expressed?
Question: How is the slump test made?
Question: Does the method of molding test specimens affect the test results?
Question: Are load tests on completed structures ever employed?
Question: Is pulse velocity related to strength?
Question: The difference between setting and hardening
Question: Are there data relating w/cm to flexural strength that are as reliable as those for compressive ...
Question: Unsoundness in portland cement
Question: Can tests be conducted by anyone?
Question: Why is a spherically seated bearing block required in testing cylinders?
Question: What other uses are there for the pulse velocity?
Question: How is the resistance to sulfate determined?
Question: Addition of lime in curing tanks
Question: What irregularities are to be avoided in the test specimen?
Question: Does a wet specimen test higher than a dry one?
Question: How is the resistance to freezing and thawing determined?
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