Orientation of Steel Fibers in Magnetically Driven Concrete and Mortar.

Wen Xue,Bing Feng,Fang Xie,Ju Chen

doi:10.3390/ma11010170

Abstract

The orientation of steel fibers in magnetically driven concrete and magnetically driven mortar was experimentally studied in this paper using a magnetic method. In the magnetically driven concrete, a steel slag was used to replace the coarse aggregate. In the magnetically driven mortar, steel slag and iron sand were used to replace the fine aggregate. A device was established to provide the magnetic force. The magnetic force was used to rotate the steel fibers. In addition, the magnetic force was also used to vibrate the concrete and mortar. The effect of magnetic force on the orientation of steel fibers was examined by comparing the direction of fibers before and after vibration. The effect of magnetically driven concrete and mortar on the orientation of steel fibers was also examined by comparing specimens to normal concrete and mortar. It is shown that the fibers could rotate about 90° in magnetically driven concrete. It is also shown that the number of fibers rotated in magnetically driven mortar was much more than in mortar vibrated using a shaking table. A splitting test was performed on concrete specimens to investigate the effect of fiber orientation. In addition, a flexural test was also performed on mortar test specimens. It is shown that the orientation of the steel fibers in magnetically driven concrete and mortar affects the strength of the concrete and mortar specimens.

Highlights

There has been many research studies about steel fiber reinforced concrete (SFRC) in the last four decades [1]
The direction of the steel fibers of specimen NC-S1 and magnetically driven concrete (MDC)-S1 remained vertical to the splitting direction, which means that the shaking table had almost no effect on the orientation of the steel fibers
The orientation of the steel fibers in MDC and magnetically driven mortar (MDM) was investigated in this study

Summary

Introduction

There has been many research studies about steel fiber reinforced concrete (SFRC) in the last four decades [1]. It was shown that fiber orientation has an effect on the tensile behavior of SFRC. It was shown that fiber orientation is able to significantly influence the tensile and bending behaviors of fiber reinforced concrete (FRC) by increasing the fiber efficiency to bridge cracks [4,5,6,7,8]. The electromagnetic device is effective in orienting fibers in the direction aligned to the applied magnetic field. The steel fibers close to the surface of the mold cannot rotate freely when subjected to the magnetic field. Since the aggregates in MDC and MDM move under the magnetic force, the steel fibers may be able to rotate freely when subjected to the magnetic field. Experimental investigation on slabs with steel reinforcing bars will be studied in the test program

Experimental Investigation

Test Results

Conclusions