Experimental study on creep of short performance-based alkali-activated concrete column

Abstract

Performance-based alkali-activated concrete overcomes the fatal disadvantage of short setting time and poor workability. In this paper, The creep test of this kind of concrete is carried out to explore the influence of strength grade and reinforcement ratio on the creep coefficient under the condition of constant temperature and humidity environment. Results show that specific creep and creep coefficient of alkali activated concrete decrease with strength grade. The ratio of creep coefficients of C30, C50 and C70 is 1:0.89:0.80. The creep coefficients were compared with the creep models adopted by the American Code, the European Code, and the Chinese Code, which are not suitable for predicting the creep coefficient of alkali-activated concrete. At the same time, considering the use of reinforcement in practical applications, the effect of reinforcement ratio on the creep coefficient of alkali-activated concrete is studied. The results show that reinforcement can reduce the creep coefficient. The greater the reinforcement ratio, the smaller the creep coefficient. The creep coefficient of alkali-activated concrete with reinforcement ratio of 1.1% and 2.0% is 11.1% and 18.7% smaller than that of concrete without reinforcement. Based on the aging theory method, according to the force balance condition and deformation coordination condition, the creep coefficient calculation formula considering the influence of the steel bar can be deduced. The theoretically calculated value is in good agreement with the measured data. This formula can be used to predict the creep coefficient of alkali-activated reinforced concrete.