Combined e ect of silica fume and polypropylene ber on drying shrinkage properties of concrete compositescontaining y ash

A parametric experimental study has been conducted to investigate the combined eect of silica fume and polypropylene ber on the workability and drying shrinkage of concrete composite containing y ash. Four contents of y ash, four silica fume contents and four dierent ber volume fractions were used. The results indicate that y ash can not only improve the workability but also lower the drying shrinkage of the concrete composite. The workability of the concrete composite becomes better and better and the drying shrinkage strain is decreasing gradually with the increase of y ash content. Besides, silica fume has adverse eect on both of the workability and drying shrinkage property of concrete composite containing y ash. With the increase of silica fume content, both the slump and slump ow of the concrete containing y ash decrease gradually, while the drying shrinkage strain has an increasing tendency. In addition, polypropylene ber can greatly restrict the drying shrinkage of concrete composite containing y ash and silica fume, and there is a tendency of decrease in the drying shrinkage strain with the increase of ber volume fraction. However, polypropylene ber has a little adverse eect on the workability of concrete composite.