Effect of Chopped Basalt Fibers on the Mechanical Properties and Microstructure of High Performance Fiber Reinforced Concrete

Tehmina Ayub,Nasir Shafiq,M Fadhil Nuruddin

doi:10.1155/2014/587686

Abstract

This paper presents the mechanical properties and the microstructure of the high performance fiber reinforced concrete (HPFRC) containing up to 3% volume fraction of chopped Basalt fibers. Three types of the concrete were prepared, out of which, the first type was prepared by utilizing 100% cement content. The other two types of the concrete were prepared by replacing 10% cement content with silica fume and the locally produced metakaolin. Using each concrete type, four mixes were prepared in which Basalt fibers were added in the range of 0–3%; that is, total twelve mixes of the HPFRC concrete were prepared. From each of the twelve concrete mixes, total twelve specimens were cast to determine the mechanical properties of the HPFRC including compressive strength (cube and cylinder), splitting tensile strength, and the flexural strength. In this way, a total of 108 specimens were cast and tested in this study. Test results showed that the addition of the Basalt fibers significantly increased the tensile splitting strength and the flexural strength of the HPFRC, while there was slight improvement in the compressive strength with the addition of Basalt fibers. The microstructure of HPFRC was examined to determine the interfacial transition zone (ITZ) between the aggregates and the paste by using field emission scanning electron microscope (FESEM), which showed the improvement of the ITZ due to the addition of the Basalt fibers.

Highlights

The mechanical properties of the concrete significantly depend on the microstructure, especially on the pore structure
The pore structure of the concrete can be improved by using mineral admixtures, which alongside improves the properties of the fresh concrete, [1], hardened concrete [2], and the durability of the concrete [3]
The variation in the average cube and cylinder strengths of high performance fiber reinforced concrete (HPFRC) containing Basalt fibers was found to be in the range of ±4% compared to the average compressive strength of the control specimens

Summary

Introduction

The mechanical properties of the concrete significantly depend on the microstructure, especially on the pore structure. Authors investigated the mechanical properties of the three types of high performance fiber reinforced concrete (HPFRC) containing chopped Basalt fibers. In the second and the third concrete type, 10% cement content was replaced with the silica fume and the locally produced metakaolin, respectively. The information on the microstructure and the mechanical properties of the HPFRC containing 1 to 3% fiber volumes is provided due to research gap in the literature pertaining to the use of moderate to higher volume of Basalt fibers in concrete. In order to achieve this objective, an experimental investigation was carried out to observe the behavior of the HPFRC with a cylinder compressive strength in the range of 73 to 85 MPa using 0–3% of Basalt fiber volume. Silica fume and locally produced metakaolin were used as partially cement replacing material to observe the effect on the strength increase. The empirical relationship between the fiber volume and the mechanical properties of the HPFRC was proposed

Experimental Program

Test Results and Discussion

Conclusion