## 5 Conclusions  
In this study, the mechanical and time-dependent properties, particularly the creep of AAS concrete with five different stress-strength ratios (0.15, 0.3, 0.45, 0.6, and 0.75), were studied. After comparing the creep of AAS concrete using the current models (ACI 209R-92, B3, CEB-FIP 2010, and GL2000), we analyzed the cause of the deviation and proposed an improved creep model for AAS concrete with a wide range of stress-strength ratios based on the GL2000 model. The main conclusions drawn are as follows:  
1. The AAS concrete shows greater compressive strength (for _w/c_ ratio = 0.5) but a lower elastic modulus than OPC concrete.
2. At a stress-strength ratio of 0.15-0.75, the creep of AAS concrete has a convergent nonlinear stage and a non-convergent stage but not an obvious linear stage. This phenomenon differs from OPC concrete, which has a linear creep stage and is typically under a stress-strength ratio of 0.4. The dividing points of the convergent nonlinear creep and non-convergent creep of AAS concrete are above 0.6 and approximately 0.75, which are quite similar with those of OPC concrete.
3. AAS concrete basically has a consistent creep coefficient under a stress-strength ratio of 0.15-0.6 and provides a convenient way to achieve a creep prediction. This property differs with OPC concrete, which has different creep coefficients between the service stress (usually under 0.4) and high stress-strength ratio (usually above 0.4).
4. The rate of three parameters (stress-dependent strain, specific creep, and creep coefficient) of AAS concrete decrease near linearly by the dual-logarithmic scale. This regularity can make it more convenient for us to understand and predict the long-term creep behavior of AAS concrete.
5. The four creep models are good at predicting the creep coefficient, but not the specific creep and stress-dependent strain of AAS concrete. AAS concrete exhibits greater elastic strain and creep than OPC concrete under the same parameters. As the reason for this, the elastic modulus of AAS concrete with the same strength as OPC concrete is not similar to the elastic modulus calculated by the models.
6. By applying the actual elastic modulus, except for the B3 model, the models can predict the specific creep and stress-dependent strain of AAS concrete with a stress-strength ratio of 0.3 or better. This is due to the B3 model calculating the parameters belonging to the specific creep, and during this period, without directly inputting the elastic modulus.
7. The secant modulus of AAS concrete is sensitive to the stress-strength ratio. The secant modulus decreases linearly with an increase in the stress-strength ratio. We thus proposed a formula to calculate the secant modulus of AAS concrete.
8. Based on the GL2000 model and using the secant modulus to replace the elastic modulus, we proposed an improved creep model for AAS concrete with a wide range of stress-strength ratios.  
Investigation, X.Z.; resources, W.Z.; data curation, X.Z. and Y.Z.; writing--original draft preparation, X.Z.; writing--review and editing, X.Z and P.C.; supervision, W.Z.; project administration, W.Y.; funding acquisition, W.Y.  
This research was funded by the National Natural Science Foundation of China, grant number 51478142.  
The authors declare no conflict of interest.