Newmark Structural Engineering Laboratory

Department of Civil and Environmental Engineering

College of Engineering

University of Illinois at Urbana-Champaign

   
 
   
         
 
 
Recent and Past Projects
NSEL Reports Series

Early Age Creep-shrinkage of High Performance Concrete (HPC)

 

Principal Investigator: Prof. D. Lange

Research Assistant: Matthew D'Ambrosia

Volumetric instability of cement-based matrices is one of the primary causes for early age cracking of concrete pavements and structures. Creep and shrinkage of concrete under restrained conditions during the first days after casting have been characterized by an experiment that provides data on shrinkage and tensile creep strains, restrained shrinkage stress, and the extent of stress relaxation by tensile creep mechanisms.

This experiment was a uniaxial test that could reproduce restrained conditions or apply constant compressive or tensile loads to the specimen. High performance concrete, fiber reinforced concrete, and normal concrete materials were evaluated. 

The analysis differentiated components of early age deformation: autogenous shrinkage, drying shrinkage, basic creep, and drying creep. The modeling views the components of strain as a superimposed, but coupled phenomena. The basic creep model utilizes the concept of solidification theory, and an analysis to separate basic and drying creep has been developed.

The study documented very high rates of creep within the first three days, and demonstrated that common creep equations (e.g. ACI Building Code) need to be modified to describe early age.

If you are interested in this project or you have any questions please email Prof. D. Lange at dlange@illinois.edu

 
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