Experimental Investigation and Modelling of the Layered Concrete with Different Concentration of Short Fibers in the Layers

Abstract

The use of steel fiber reinforced concrete (SFRC) in structures with high physical-mechanical characteristics allows engineers to reduce the weight and costs of the structures, to simplify the technology of their production, to reduce or completely eliminate the manual labor needed for reinforcement, at the same time increasing reliability and durability. Commonly accepted technology is exploiting randomly distributed in the concrete volume fibers with random each fiber orientation. In structural members subjected to bending, major loads are bearing fibers located close to outer member surfaces. The majority of fibers are slightly loaded. The aim of the present research is to create an SFRC construction with non-homogeneously distributed fibers. We prepared layered SFRC prismatic specimens. Each layer had different amount of short fibers. Specimens were tested by four point bending till the rupture. Material fracture process was modelled based on the single fiber pull-out test results. Modelling results were compared with the experimental curves for beams. Predictions generated by the model were validated by 4PBT of 100 × 100 × 400 mm prisms. Investigation had shown higher load-bearing capacity of layered concrete plates comparing with plate having homogeneously distributed the same amount of fibers. This mechanism is strongly dependent on fiber concentration. A high amount of fibers is leading to new failure mechanisms—pull-out of FRC blocks and decrease of load-bearing capacity. Fracture surface analysis was realized for broken prisms with the goal to analyze fracture process and to improve accuracy of the elaborated model. The general conclusion with regard to modelling results is that the agreement with experimental data is good, numeric modelling results successfully align with the experimental data. Modelling has indicated the existence of additional failure processes besides simple fiber pull-out, which could be expected when fiber concentration exceeds the critical value.

Concrete Reinforced by Hybrid Mix of Short Fibers under Bending

“…Samples with SF and ARG fibers exhibited better mechanical behaviour as compared to 4PBT after 28 days. Fibers remained in the matrix of initially cracked concrete; this effect points to one of the main factors responsible for effective transfer of the applied load, which correlated well with the results of studies by other authors, for example, [48][49][50][51][52].…”

Testing the Physical and Mechanical Properties of Polyacrylonitrile Nanofibers Reinforced with Succinite and Silicon Dioxide Nanoparticles

“…In the past, one of the main engineering challenges was the development, introduction, and mass production of efficient materials in all industrial areas. Different fiberreinforcement options are used in various fields [1][2][3][4][5], including the use of various materials and technologies [6][7][8][9]. Due to its superior physical characteristics, such as low density, thermal constancy, high strength, and modulus of elasticity, polyacrylonitrile (PAN) is a commercially important semicrystalline polymer [10,11].…”

Optimal Sensor Placement in Composite Circular Cylindrical Shells for Structural Health Monitoring

“…A huge number of various materials are produced in the modern world, differing in their technical characteristics, features of application and operation [1][2][3]. The development of modern technology requires new structural materials which are superior in strength, elasticity and other properties the traditional ones.…”