Creep and Shrinkage of Reinforced Thin-Shell Concrete

摘要

Creep coefficients and shrinkage factors were determined for specimens of three thin-shell reinforced concretes consisting of one normal-weight concrete, one sand-lightweight concrete, and one all-lightweight concrete. Prismatic specimens were tested in thicknesses of 1 inch, 2 inches, and 4 inches at stress-strength ratios of 0.15 and 0.50. Specimens were tested in controlled relative humidities of 25%, 50%, 70%, and 100%, with temperature at 73 degrees F in all locations. Curves involving surface-area-to-volume ratios were used to determine time-dependent strains for different humidities, sizes, and stresses. Equations are presented for creep coefficients and for shrinkage; curves are presented for obtaining correction factors to be used in design equations. Correction curves for unit weight were developed with test data from this study. Predicted values for creep coefficients and shrinkage agreed with observed data when computed with equation and correction factors presented herein. (Author)