Mesomechanical model for concrete creep with viscoelastic interface transition zone

The interface transition zone (ITZ) effect on concrete creep performance was analyzed in this study. The ITZ was treated as a weakened matrix, which mechanical behavior could be described by the Burgers model. The proposed prediction model of concrete creep took account of the ITZ's viscoelasticity by combining the generalized self-consistent Mori-Tanaka method with the Laplace transformation principle. The model's experimental validation confirmed that it accurately simulated the creep behavior of concrete specimens with various fly ash and ground slag ratios. The existence of viscoelastic ITZ promotes the creep of concrete, and the maximum creep growth rate was attained in the concrete specimen with 60% ratio of fly ash. The effects of ITZ thickness and other parameters, the volume fraction of aggregates, and particularly ITZ contribution to concrete creep in the concrete specimens with five mix proportions at different loading ages were clarified and discussed in detail.

Automated summary

This study analyzed the effect of the interface transition zone (ITZ) on the creep performance of concrete and proposed a prediction model considering the viscoelasticity of the ITZ. Experimental validation showed that the model accurately simulated the creep behavior of concrete specimens with different ratios of fly ash and ground slag. It was found that the presence of a viscoelastic ITZ promoted concrete creep.