Rheological Features and Hereditary Models of Lightweight Sintered Aggregate Concrete Under Cyclic Loading

This article compares the analytical results from two models, based on the theory of hereditary creep strain, with experimental results on the rheological properties of lightweight sintered aggregate concrete under cyclically varying loads. In a previous article, the authors analyzed the adequacy of standard models for the same test results. Because the use of standard models is very complex and does not improve the approximation of test results without additional calibration, the authors suggest reconsidering the use of hereditary models for LWAC. The application of four such long-term models was analyzed. Among these models, the Arutiunian theory of hereditary creep with aging and the modified hereditary theory with Bažant aging function yielded quantitatively and qualitatively correct results. The application of hereditary creep theory allowed for the formulation of the total strain as a superposition of strain increments, obtained by an integral equation. This equation was applied to a series of constant stress increments and decrements, as in the case of cyclic loading, and it was mathematically described in segmented form. Knowledge of the properties of LWAC and useful long-term models is essential for the design of prestressed structures made of lightweight aggregate concrete subjected to time-varying loads.