ملخص الدراسة:

Shrinkage in concrete is a problem which faces most of concrete structures especially in the horizontal surface that causes cracks. Drying shrinkage cracks are caused by evaporation of water of cement paste after setting, where rapid evaporation occurs. The rapid evaporation destroys the integrity of the surface and reduces its durability. To increase the life of a concrete structure, it is necessary to minimize the formation of drying shrinkage cracks. The main goal of this research is to minimize drying shrinkage of concrete using steel and polypropylene fibers (forta ferro) that are available in local markets at several percentages. It is also aimed at studying the effect of fibers on physical properties of concrete. Many trial mixes were prepared to improve the mechanical properties compare with that’s of mixes without fibers. This research comprises two phases: the first phase is to study the effect of steel and polypropylene fibers (forta ferro) on shrinkage properties of concrete by different percentage (0.5% ,1.0 % and 1.5% of volume) of fibers according American standard (ASTM C -157). The second phase is to study the effect of forta ferro and steel fiber on the fresh and hardened mechanical properties of concrete such as, workability, compressive strength and split cylinder strength, by different percentage of steel and forta ferro fibers. The results showed that steel fibers reduced shrinkage in normal concrete by up to 16.4% at 1.5% , while the forta ferro fibers reduced the shrinkage in normal concrete by up to 38.31% at 1% . The results also showed that the steel and forta ferro fibers improved the compressive strength up to 13% and splitting strength up to 35% .

توثيق المرجعي (APA)