Combined effect of silica fume and steel fibers on the impact resistance and mechanical properties of concrete

This study investigated the impact resistance and mechanical properties of steel fiber-reinforced concrete with water-cement ratios of 0.46 and 0.36, with and without the addition of silica fume. Hooked steel fibers with 60-mm length and an aspect ratio of 80, with three volume fractions of 0%, 0.5%, and 1% were used as the reinforcing material. In pre-determined mixtures, silica fume is used as a cement replacement material at 8% weight of cement. The experimental results show that incorporation steel fibers improve the strength performance of concrete, particularly the splitting tensile and the flexural strengths. A remarkable improvement was observed in impact resistance of the fibrous concretes, as compared with the reference materials. The results demonstrate that when steel fiber is introduced into the specimens including silica fume, the impact resistance and the ductility of the resulting concrete are considerably increased. © 2010 Elsevier Ltd. All rights reserved

Evaluation of engineering properties of calcium sulfoaluminate cement-based concretes reinforced with different types of fibers

Calcium sulfoaluminate (CSA) cement has recently gained increased attention due to its lower amount of CO2 emissions, as compared to that of the ordinary Portland cement (OPC). This paper evaluates the impact of different types of fibers on the engineering features of CSA-based concretes at different water-cement ratios of 0.35 and 0.28. In this study, metallic fibers including double hooked-end steel fibers and hooked-end steel fibers, and non-metallic fibers (i.e., polyvinyl alcohol (PVA) fibers) were utilized at fiber content of 1%. The mechanical properties of concretes were assessed at different curing ages. Dimensional stability of the concrete mixes was also examined. The morphology of the fractured specimens was studied by using the SEM method. The results indicate that the engineering properties of concrete were improved by introducing fibers to the concrete, irrespective of fiber type. The results show that DHE steel fiber has an important effect on the flexural performance of CSA cement-based concretes and results in deflection-hardening behavior. It was observed that fibers and particularly PVA fibers cause a decrease in shrinkage deformation. Microstructure tests demonstrate that prismatic ettringite is the main hydration product of CSA cement-based concrete. The SEM observation also confirms that the inclusion of CSA cement in concrete improves the cohesiveness between the fibers and cement matrix

Mechanical and durability properties of high-strength concrete containing steel and polypropylene fibers

Abstract not available.Vahid Afroughsabet, Togay Ozbakkalogl

Preliminary Assessment on Durability of High Performance Fiber Reinforced Concrete with CSA Cement

Concrete industry produces a great environmental impact. The total, or partial, substitution of ordinary Portland cement (OPC) with Calcium sulfoaluminate (CSA) cement could be a possible solution, due to its lower production temperature and thus lower CO2 emission. Therefore, there is an essential need to assess the durability properties of concrete produced with CSA cement. In this work a preliminary study on durability of high performance fiber reinforced concretes produced with CSA cement in total or partial substitution of OPC, also with ground granulated blast-furnace slag (GGBS), was performed. Compressive strength and electrical resistivity of the different concrete mixes and electrochemical tests to evaluate corrosion condition of the embedded steel fibers, were assessed. The results show that substitution of OPC with CSA cement improves the mechanical properties of concrete but promotes corrosion of the steel fibers, affecting the durability of this material

The long-term compressive strength and durability properties of silica fume fiber-reinforced concrete

The long-term compressive strength and durability properties of concrete specimens produced by incorporating polypropylene fibers and silica fume were investigated. Silica fume, a cement replacement, was used at 8% (by weight of cement) and the volume fractions of the polypropylene fibers were 0%, 0.2%, 0.3% and 0.5%. Water-binder ratios were 0.46 and 0.36. The results indicate that the inclusion of fiber and particularly silica fume into the specimens led to an increased long-term compressive strength. Electrical resistance of the silica fume specimens improved remarkably, but decreased slightly due to the fiber inclusion. Water absorption of the fiber-silica fume specimens decreased exclusively compared to the reference samples. Inclusion of fiber and silica fume into the specimens had no considerable effect on the dynamic frequency results. © 2011 Elsevier B.V

Property assessment of steel-fibre reinforced concrete made with silica fume

When silica fume was used as a cement replacement, it enhanced the effectiveness of added steel fibre on the properties of concrete. Three different steel fibres were used at 0.0%, 0.5% and 1.0% by volume of concrete. Silica fume was introduced at 8% by weight of cement into the concrete mixtures that were made with water-cement ratios of 0.46 and 0.36. The early- and later-stage compressive strength, the electrical resistivity, the water absorption and the dynamic frequency of the specimens were examined. The results indicate that the inclusion of steel fibre in silica fume specimens led to the highest long-term compressive strength and the lowest resistivity. Furthermore, an improvement in the dynamic frequency and a decrease in water absorption were attained in 1% steel fibre silica fume specimens. © 2011 Elsevier Ltd. All rights reserved

Evaluation of Engineering Properties of Calcium Sulfoaluminate Cement-based Concretes Reinforced with Different Types of Fibers

Calcium sulfoaluminate (CSA) cement has recently gained increased attention due to its lower amount of CO2 emissions, as compared to that of the ordinary Portland cement (OPC). This paper evaluates the impact of different types of fibers on the engineering features of CSA-based concretes at different water-cement ratios of 0.35 and 0.28. In this study, metallic fibers including double hooked-end steel fibers and hooked-end steel fibers, and non-metallic fibers (i.e., polyvinyl alcohol (PVA) fibers) were utilized at fiber content of 1%. The mechanical properties of concretes were assessed at different curing ages. Dimensional stability of the concrete mixes was also examined. The morphology of the fractured specimens was studied by using the SEM method. The results indicate that the engineering properties of concrete were improved by introducing fibers to the concrete, irrespective of fiber type. The results show that DHE steel fiber has an important effect on the flexural performance of CSA cement-based concretes and results in deflection-hardening behavior. It was observed that fibers and particularly PVA fibers cause a decrease in shrinkage deformation. Microstructure tests demonstrate that prismatic ettringite is the main hydration product of CSA cement-based concrete. The SEM observation also confirms that the inclusion of CSA cement in concrete improves the cohesiveness between the fibers and cement matrix

High-performance fiber-reinforced concrete: a review

In recent years, an emerging technology termed, "High-Performance Fiber-Reinforced Concrete (HPFRC)" has become popular in the construction industry. The materials used in HPFRC depend on the desired characteristics and the availability of suitable local economic alternative materials. Concrete is a common building material, generally weak in tension, often ridden with cracks due to plastic and drying shrinkage. The introduction of short discrete fibers into the concrete can be used to counteract and prevent the propagation of cracks. Despite an increase in interest to use HPFRC in concrete structures, some doubts still remain regarding the effect of fibers on the properties of concrete. This paper presents the most comprehensive review to date on the mechanical, physical, and durability-related features of concrete. Specifically, this literature review aims to provide a comprehensive review of the mechanism of crack formation and propagation, compressive strength, modulus of elasticity, stress-strain behavior, tensile strength (TS), flexural strength, drying shrinkage, creep, electrical resistance, and chloride migration resistance of HPFRC. In general, the addition of fibers in high-performance concrete has been proven to improve the mechanical properties of concrete, particularly the TS, flexural strength, and ductility performance. Furthermore, incorporation of fibers in concrete results in reductions in the shrinkage and creep deformations of concrete. However, it has been shown that fibers may also have negative effects on some properties of concrete, such as the workability, which get reduced with the addition of steel fibers. The addition of fibers, particularly steel fibers, due to their conductivity leads to a significant reduction in the electrical resistivity of the concrete, and it also results in some reduction in the chloride penetration resistance of the concrete