ACI and its members disclaim liability for damages of any kind, including any special, indirect, incidental, or consequential damages, including without limitation, lost revenues or lost profits, which may result from the use of this publication. It is the responsibility of the user of this document to establish health and safety practices appropriate to the specific circumstances involved with its use. ACI does not make any representations with regard to health and safety issues and the use of this document.
The user must determine the applicability of all regulatory limitations before applying the document and must comply with all applicable laws and regulations, including but not limited to, United States Occupational Safety and Health Administration OSHA health and safety standards. Phone: Fax: www.
Ackers Richard D. Gaynor Colin L. Luciano Luke M. Barringer Thomas M. Greene Allyn C. Luke Patrick J. Sullivan F. Haddad Stephen S. Brown Kal R. Hindo Richard E. Miller Michael A. Castles Robert S. Jenkins Venkataswamy Ramakrishnan Roger E. Vaughan James E. Cook Alfred L. Kaufman Jr. Reddy Woodward L. Dilly William F. Kepler David N.
Werner II Donald E. Dixon Michael L. Leming James M. Shilstone Jr. Information derived from such procedures is valuable Chapter 1—Introduction, p. This guide discusses variations that occur 1. Chapter 2—Notation and definitions, p. This document is intended for the use of individuals who are competent to evaluate the strength significance and limitations of its content and recommendations 3.
The American Concrete Institute disclaims any and all responsibility for the stated principles. The Institute shall not be liable for any loss or damage arising therefrom. Reference to this document shall not be made in contract ACI R supersedes R and was adopted and published April Chapter 5—Criteria, p.
The characteristics of 5. Statistical procedures provide valuable tools when evaluating Chapter 6—Evaluation of data, p. Information derived from them is also 6. This 6. Random sampling is when each 7. Natrella , Box et al. Procedures described are ASTM D discuss the need for random sampling, and applicable to the compressive strength test results required provide a useful short table of random numbers.
Statistical concepts described are applicable for the analysis 1. Chapter 4 materials. This guide assumes that the concrete test results presents the statistical tools that are used to analyze and conform to a normal distribution.
Chapters 5 and 6 review statistically- Canada require routine sampling of concrete and fabrication based specifications. They are molded and cured 2. If the concrete is so deviation from average range Table 4.
Variability in strength-producing properties of the concrete termed swithin-batch mixture and production process, some causes of which are listed under the batch-to-batch variations in Table 3. Definitions provided herein largely governed by the water-cementitious material ratio complement that resource.
Because the quantity sample of concrete. There is an inverse relationship between strength individually does not constitute, a test result. The air content of a normal distribution—a frequently occurring natural specific concrete mixture can vary depending on variations in distribution that has predictable properties.
The analysis of constituent materials, extent of mixing, and ambient site strength test results presented in this guide assumes that the conditions. For good concrete control, the entrained air test results under consideration are normally distributed. Although this assumption is reasonable, it is not always the The temperature of fresh concrete affects the amount of case; users should check the actual distribution of the data to water needed to achieve the proper consistency and ensure it is reasonably close to normally distributed.
In addition, the concrete temperature single cylinder strength— also known as individual during the first 24 hours of curing can significantly affect strength is the compressive strength of a single cylinder later-age strengths of the concrete.
The known performance of admixtures at normal temperatures within-batch range—the difference between the may be different at extremely low or high temperatures. The maximum and minimum strengths of individual concrete performance of an admixture when used by itself may be specimens that comprise one strength test result.
Sometimes different if it is used in combination with another admixture. When referring to a test of two Construction practices can cause variations of in-place cylinders, the within-batch range is sometimes called the strength due to inadequate mixing, improper consolidation, pair-difference.
Laboratory equipment and Batch-to-batch variations Within-batch variations procedures should be calibrated and checked periodically. Variations in characteristics and Improper sampling from the batch Testing personnel should be trained ACI Certified Technicians proportions of ingredients: sample. Variations in placing, and one cylinder. Figure 4. A mathematical characteristic of the normal distribution is that These differences will not be reflected in deviation from the mean, and that Also on the chart is a histogram of the measured test results sorted into strength 3.
Each dot represents a test, which indicates that this Testing to determine compliance with contract specifications data set is normally distributed. Plotting histograms is one of should be conducted according to the methods specified in the easiest ways to check the data for normality. Acceptance tests assess the compressive distribution cannot always be assumed. A normal distribution strength of the concrete when prepared and cured under is appropriate in most cases when the concrete strength does standard conditions, not the in-place strength.
It is not the not exceed 10, psi 70 MPa Cook However, purpose of such tests to determine the in-place strength of the Cook further reported that a skewed distribution may structure, but rather to assure that the concrete delivered and result for high-strength concrete when the limiting factor is placed was the concrete specified.
Deviations in field the aggregate strength. When data are not symmetrical about sampling, specimen preparation, curing, and testing procedures the mean, but concentrated to the right or left, the distribution is may cause lower strength test results. Field sampling, said to be skewed. When a distribution curve is either too making, curing, handling, and testing of specimens should peaked or too flat, kurtosis is said to exist. Data exhibiting be performed by ACI Certified Technicians or equivalently skewness, or kurtosis, may not be normally distributed; and trained and certified personnel.
Provisions for maintaining any analysis presuming a normal distribution may be very specified curing conditions should be made. Specimens from misleading. Skewness and kurtosis should be considered for concrete that are hardening and gaining strength should not statistical evaluation of high-strength concretes. Further discussion of Using accurate, properly calibrated testing equipment and these topics is beyond the scope of this document; interested proper sample preparation procedures is essential.
Test results readers should consult statistical references. The at least two 6 x 12 in. X2 is the second strength calculated as shown in Eq.
The population standard deviation where s is the statistical average standard deviation, or consists of all possible data, often considered an infinite pooled standard deviation, determined from two records; sA number of data points. The sample is a portion of the and sB are the standard deviations of Records A and B, population, consisting of a finite number of data points. The latter equation is 4. Many computer software packages calculate estimating dispersion in the absence of statistically valid statistical functions.
When using such programs, take care to sample sizes. Advanced embedding details, examples, and help! Packet inserted on p. The book has spent more than five years on bestseller lists and ignited a global conversation, while StrengthsFinder has helped millions discover their top five talents.
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There are no reviews yet. Be the first one to write a review. Books for People with Print Disabilities. Internet Archive Books. Procedure that the lines marked on the ends of the specimen are vertical 7.
Place a second plywood specimen using a suitable device that will ensure that they are strip lengthwise on the cylinder, centered on the lines marked in the same axial plane see Fig. Position the assembly to ensure the alternative, use the aligning jig shown in Fig. Record the maximum applied load indicated by the testing machine at failure.
Note the type of failure and the appearance of the concrete. NOTE 3—The relationship between splitting tensile stress and applied 7. Calculation where: 8. Available research data,3 however, 9.
Results of two properly conducted tests on the same 9. Keywords 9. Approved July 1, 1 Reversed the order of units in the test method so that SI units appear first. ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard.
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