The Clusters Model For Creep Of Fly Ash Concrete

Fly ash concrete, because of its good construction, durability performance and environmental compatibility, has being largely and widely used in civil engineering. Creep, as an important indicator of long-term performance of concrete, has been attracted great attention to the academic and engineering. In recent years, scholars did a large number of experimental studies and theoretical explorations of the fly ash concrete creep properties, and projected some prediction models of fly ash concrete creep. However, these models are the description of the test results in the level of phenomenon, lack of rational explanation, and the rationality remains untested. In this paper, a clusters model of fly ash concrete creep was found, applying the related theories of fly ash concrete, the maturity and rheology model. Fly ash concrete is considered as two phase materials of coarse aggregate and cement mortar, while the cement mortar is virtualizated as the evolving assemble of cluster units relevant with as hydration process. Creep of fly ash concrete is the macro performance of coarse aggregate elastic deformation and visco elastic plastic deformation of clusters units. From the multi-scale perspective, the model considered the fly ash shape effect, micro-aggregate effects in concrete, and its role of the hydration process, offering a more reasonable mechanism explanation of fly ash concrete creep. The loading age effect; during loaded, the stress distribution and deformation between the coarse aggregate and cement mortar; when the new cluster unit forms with hydration, stress re-distribution between cluster units. By fitting the experimental data, the cluster unit rheological parameters of different fly ash content concrete were determined. Comparison with other experimental and models shows the applicability of the proposed model is strong and this model is more accurate. Finally using the model loading age and coarse aggregate, cement ratio parameters were analyzed, and the laws of fly ash concrete creep are present.Clusters model of fly ash concrete creep gives rational mechanism explanation of fly ash concrete creep, providing a new choice for the fly ash concrete creep prediction.