ACI 209.2R-08 - Guide for Modeling and Calculating Shrinkage and Creep in Hardened Concrete

This guide is intended for the prediction of shrinkage and creep in compression in hardened concrete. It may be assumed that predictions apply to concrete under tension and shear. It outlines the problems and limitations in developing prediction equations for shrinkage and compressive creep of hardened concrete. It also presents and compares the prediction capabilities of four different numerical methods. The models presented are valid for hardened concrete moist cured for at least 1 day and loaded after curing or later. The models are intended for concretes with mean compressive cylindrical strengths at 28 days within a range of at least 20 to 70 MPa (3000 to 10,000 psi). This document is addressed to designers who wish to predict shrinkage and creep in concrete without testing. For structures that are sensitive to shrinkage and creep, the accuracy of an individual model’s predictions can be improved and their applicable range expanded if the model is calibrated with test data of the actual concrete to be used in the project. 45pp.

Contents:

Chapter 1-Introduction and scope
• 1.1-Background
• 1.2-Scope
• 1.3-Basic assumptions for development of prediction models
Chapter 2-Notation and definitions
• 2.1-Notation
• 2.2-Definitions
Chapter 3-Prediction models
• 3.1-Data used for evaluation of models
• 3.2-Statistical methods for comparing models
• 3.3-Criteria for prediction models
• 3.4-Identification of strains
• 3.5-Evaluation criteria for creep and shrinkage models
Chapter 4-Model selection
• 4.1-ACI 209R-92 model
• 4.2-Bažant-Baweja B3 model
• 4.3-CEB MC90-99 model
• 4.4-GL2000 model
• 4.5-Statistical comparisons
• 4.6-Notes about models
Chapter 5-References
• 5.1-Referenced standards and reports
• 5.2-Cited references
Appendix A-Models
• A.1-ACI 209R-92 model
• A.2-Bažant-Baweja B3 model
• A.3-CEB MC90-99 model
• A.4-GL2000 model
Appendix B-Statistical indicators
• B.1-BP coefficient of variation method (ϖBP%)
• B.2-CEB statistical indicators
• B.3-The Gardner coefficient of variation (ωG)
Appendix C-Numeric examples, p. 209.2R-30
• C.1-ACI 209R-92 model solution
• C.2-Bažant-Baweja B3 model solution
• C.3-CEB MC90-99 model solution
• C.4-GL2000 model solution
• C.5-Graphical comparison of model predictions