Compressive Creep Behavior of Cellulose Fiber Reinforced Concrete

Abstract

The effect of cellulose fiber on the long-term compressive creep performance of concrete was clarified. For this, the long-term compressive creep properties of four cellulose fiber reinforced concrete (CFRC) groups with contents of 0, 0.9 kg/m3, 1.1 kg/m3, and 1.3 kg/m3 were investigated using a spring creep tester. Loading ages of 7 days, 14 days, and 28 days, and a loading stress ratio of 0.40 were employed. Furthermore, the creep model of CFRC was established. The results revealed that the creep of concrete at three loading ages decreases by 16%, 12%, and 17%, respectively, after adding cellulose fiber to the concrete. With increasing loading age, the difference of creep degree of CFRC with different cellulose fiber content decreased gradually. Furthermore, the range of specific creep decreased from 8 × 10−6 / MPa for a 7 day loading age to 2 × 10−6 / MPa for a 28 day loading age. The change regulation of CFRC creep coefficient was similar to that of the specific creep. The influence of the cellulose fiber on the creep performance of the concrete was reflected in two aspects. On the one hand, the internal curing effect of cellulose fiber can optimize the microstructure of concrete and reduce the creep deformation. On the other hand, the fiber increases the water migration channel and defects of interface transition zone, which will increase the creep deformation. The power exponential function model for CFRC creep provided a good description of the relationship between creep and loading age and holding time. This model can be used to predict the long-term creep of CFRC under different loading ages.