Influence of mineral powder content and loading age on creep behavior of concrete members under axial compression

The effects of different test parameters on the creep of axially compressed concrete members were investigated under standard test conditions, considering loading ages of 7, 14 and 28 days and mineral powder admixtures of 0, 15%, 25% and 35%, respectively. The test results show that the creep of concrete decreases with the increase of mineral powder content when the loading age was fixed. When the content of mineral powder was unchanged, the creep of concrete would decrease with the increase of loading age. Based on the CEB-FIP MC 1990 concrete creep calculation model, the creep correction coefficient of mineral powder concrete considering the strength of mineral powder concrete, mineral powder content and loading age was proposed. The formula for the concrete creep correction coefficient which considers the loading age and mineral powder content was established by combining the existing creep test data and the test results of mineral powder concrete strength with the different loading ages and mineral powder contents in this paper. The comparison of the CEB-FIP MC 1978 and experiment values shows that the proposed formula in this paper can predict the development of creep of mineral powder concrete better. Finally, using the creep coefficient formula of mineral powder concrete, the creep coefficient values of concrete under different loading ages and mineral powder contents in CEB-FIP MC 1990 code were modified.