Response of concrete structures subject to material aging and volume instability.

摘要

Volume instability of concrete has been an important issue in construction of concrete structures as the consequence of volume instability alters the original configuration of the structures intended by engineers, hence the structural system may encounter unexpected behaviors. The primary interest of this research is the behavior of a concrete structure subject to volume instability issues. The research focused on the internal relative humidity and temperature as the sources of volume instability. Experimental and analytical program were designed and conducted for the research.; A material model was developed to describe the behavior concrete including material aging, elastic response, creep, drying shrinkage, and thermal expansion. Based on the material model, a three-dimensional finite element analysis code, named ICON (Illinois CONcrete), was developed for the numerical simulation of concrete structures under drying condition. In addition, an experimental program was conducted to obtain the material properties including strength, elastic modulus, creep, drying shrinkage, and drying profiles.; As a validation of the developed model, the behavior of three types of simple structures under drying condition was simulated using ICON, and the results were discussed and compared to experimental values. In addition, an analytical study was conducted to demonstrate the capability of the ICON code as a "prediction" tool and to assess the effect of material and geometric parameters on slab curling behavior. The research revealed the influence of material parameters, slab geometry and base properties on slab curling behavior.