Measurement and Modeling of Concrete Tensile Creep and Shrinkage at Early Age
M. D. D'Ambrosia, D. A. Lange, and Z. C. Grasley
Appears on pages(s):
creep; early age; modeling; restrained drying; shrinkage
Volumetric instability of concrete is a primary cause for early age cracking of concrete pavements and structures. Creep and shrinkage of concrete were studied under restrained conditions and under constant applied load during the first week after casting. Early age behavior was characterized by a uniaxial test that measures shrinkage strain and restrained shrinkage stress. The extent of stress relaxation by tensile creep is determined using simple superposition analysis. The experimental measurements are compared with some current creep and shrinkage models to assess their validity for early age prediction. The B3 model has been previously modified to accommodate early age creep, and this modification was employed in the current study. Test results for normal concrete mixes with different w/c are discussed and compared to model predictions. Comparisons show that the B3 model is accurate when the early age modifications are employed.