Study on the Tensile Creep Model of the Admixture of Early-Age Concrete and Application Simulation

Abstract

With respect to the recent issue related to the lack of research on tensile creep model of the admixture concrete at early age and simulation, the admixture influence function with factor of the admixture dosage was established based on composite exponential function as reference model based on existed creep rules and appropriate assumption. It has been proposed that contributing factor, c, quantitatively represented the sensitivity of concrete creep changes to the admixture and correlation between concrete creep and the admixture. The model fitting was then made after tensile creep experiment by adding different admixtures such as fly ash, slag, silica fume and polypropylene fiber in contract to reference concrete test. It indicated that the model exhibited a good fitting performance, which is practical and useful as well as readily adopted by simulation. Meanwhile, the contributing factor also demonstrated quantitatively the variation among the effect of the admixtures (fly ash, slag, silica fume and polypropylene fiber) on the tensile creep of the concrete. Finally, the model was applied to an as-built concrete project for extended simulation, the results indicated that tensile creep can effectively improve the distribution of surface tensile stress and alleviate detrimental effect due to day-night temperature differences.