Short fiber-reinforced concrete is used for purposes such as the prevention of drying shrinkage cracks and an increase in durability. Expansive additive (EX) and shrinkage-reducing admixture (SRA) have similar effects. Research undertaken to date has clarified that, when used separately, each admixture can improve the quality of concrete; however, when used in combination, their effects on the properties of concrete are still not clear. Furthermore, in Japan, the evaluation methods of concrete cracks have not been established, and various methods have been used in individual situations because concrete cracks are caused by several factors. This study therefore focused on the properties of concrete, especially drying shrinkage cracks in short fiber-reinforced concrete mixed with EX and SRA. Some types of concrete specimens in combination with two types of short fiber, EX and SRA, were made and quantitatively evaluated. The medium-fluid concrete also were made, and the fresh properties were compared with normal concrete. The results showed that to suppress dry shrinkage cracks, it was suggested that PPSFs with longer than coarse aggregate dimensions should be used, and cracks did not occur in concrete with a combination of short fibers, EX and SRA, and the effect of suppressing cracking was the highest. Furthermore, it was clarified that the medium-fluidity concrete is useful in preventing the deterioration of the flowability of concrete containing PPSFs and admixtures.
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