Fibers are effective for supplementing or replacing conventional reinforcement in non-structural and structural elements, i.e. industrial floor, road pavements, beams (shear reinforcement), slabs and tunnel linings. Although there are several benefits to using fibers as spread reinforcement, it is well-known that any type of fiber will reduce the workability, i.e. compactability, mobility and stability. In addition, there can be challenges in dispersion, where fibers entangle and result in non-uniform distribution in the concrete. The aim of this paper concerns the study of the influence of steel (rigid) and macro-synthetic (non-rigid) fibers on the fresh properties of concrete, i.e. workability and air content, as well as resultant mechanical performance. Four fiber types at two volume fractions (0.5% and 1.0%) were studied in a base concrete with a water-to-cement ratios equal to 0.45 by using the slump test, DIN flow table test and air content meter. Experimental results show that rigid and non-rigid fibers lead to different effects on the fresh properties. In addition, the combination of the slump test and DIN flow table test can give quantitative and qualitative information about the influence of fibers on concrete workability. Finally, an additional parameter for the DIN flow table test is proposed for quantifying any potential preferential flow direction.
Methods of evaluating workability for concretes reinforced by different fiber types
Veronica Guerini;Antonio Conforti;Giovanni Plizzari;
2019-01-01
Abstract
Fibers are effective for supplementing or replacing conventional reinforcement in non-structural and structural elements, i.e. industrial floor, road pavements, beams (shear reinforcement), slabs and tunnel linings. Although there are several benefits to using fibers as spread reinforcement, it is well-known that any type of fiber will reduce the workability, i.e. compactability, mobility and stability. In addition, there can be challenges in dispersion, where fibers entangle and result in non-uniform distribution in the concrete. The aim of this paper concerns the study of the influence of steel (rigid) and macro-synthetic (non-rigid) fibers on the fresh properties of concrete, i.e. workability and air content, as well as resultant mechanical performance. Four fiber types at two volume fractions (0.5% and 1.0%) were studied in a base concrete with a water-to-cement ratios equal to 0.45 by using the slump test, DIN flow table test and air content meter. Experimental results show that rigid and non-rigid fibers lead to different effects on the fresh properties. In addition, the combination of the slump test and DIN flow table test can give quantitative and qualitative information about the influence of fibers on concrete workability. Finally, an additional parameter for the DIN flow table test is proposed for quantifying any potential preferential flow direction.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.