Environmentally-friendly monofilament cellulosic fibres have been widely used as alternatives for conventional steel reinforcement within concrete. Recently, the use of cellulosic fibre fabrics and their fabric reinforced polymer composites as reinforcement materials within and/or outside of construction materials (e.g. concrete) has gained popularity due to their inexpensive cost and favourable specific mechanical properties compared with synthetic fibre fabrics (e.g. E-glass). This review presents a summary of recent development on cellulosic fibre Fabric Reinforced Cementitious (FRC) and Fabric Reinforced Geopolymer (FRG) composites, as well as their cellulosic Fabric Reinforced Polymer (FRP) composites as reinforcements of concrete, masonry and timber structures for civil engineering applications. This review covers: (1) properties (i.e. chemical composition, microstructure, mechanical properties and cost) of monofilament cellulosic fibres and their comparison with synthetic fibres, the relationship between fibre chemical composition and fibre mechanical properties, parameters affect fibre properties; (2) properties (e.g. fabrication of monofilament fibres to fabrics and structures) of cellulosic fibre fabrics, properties of polymer matrices, and properties (i.e. flexural, tensile, impact, insulation and fire properties) of cellulosic fabric FRP composites; and (3) properties (compressive, flexural and tensile and impact properties) of cellulosic FRC and FRG composites, and the properties of cellulosic FRP composites reinforced concrete, masonry and timber structures. In addition, the degradation mechanisms of cellulosic FRC and FRP are discussed. Furthermore, the durability of FRC, FRG and FRP composites are reviewed and the methods to improve the durability of FRC, FRG and FRP composites from the aspects of fibre modification and matrix modification are reviewed and summarized.

A review of recent research on the use of cellulosic fibres, their fibre fabric reinforced cementitious, geo-polymer and polymer composites in civil engineering

This paper presents the thermal and mechanical properties of bamboo fiber reinforced composite (BFRC) derived from Gigantochloa scortechinii. The bamboo fibers were prepared through chemical treatment by sodium hydroxide (NaOH) followed by physical milling method. The thermal characteristics of the bamboo fiber and its polymer composite were analysed using a thermogravimetric analysis and differential scanning calorimetric. The functional groups and crystallinity of the fiber were analysed with Fourier transform infrared and x-ray diffraction spectroscopy. Meanwhile, the fiber morphology was examined using a scanning electron microscope. The BFRCs with fiber volume fractions ranging from 0 % to 40 % embedded in three thermoset resins (epoxy, polyester, vinyl ester) were subjected to tensile and flexural tests and the fracture pattern was examined. The NaOH concentration of 10 % with soaking duration of 48 h was found to produce a bamboo fiber with the highest ultimate tensile and modulus strength. The tensile and flexural properties of all the BFRCs were found to be directly proportional to the fiber volume fractions. It was found that the bamboo fiber reinforced epoxy composite (BFREC) with 40 % fiber volume fraction exhibited the highest tensile and flexural strength compared to polyester and vinyl ester composites. The method of bamboo fiber composite preparation in this work may serve as a useful guide to produce a strong BFRC for external strengthening of buildings and structures.

Thermal and mechanical properties of bamboo fiber reinforced composites

This paper presents the results of an experimental study conducted to investigate the effectiveness of different types of fabric-reinforced cementitious matrix (FRCM) composite systems to strengthen shear critical reinforced concrete (RC) beams. Seven shear-critical RC beams were tested. The test variables included the strengthening material (glass FRCM or carbon FRCM) and the strengthening scheme (side bonded or u-wrapped). The test results revealed that FRCM strengthening is effective in enhancing the load-carrying capacity of shear-critical RC beams. The increase in load-carrying capacity of the FRCM-strengthened beams ranged between 19 and 105%. Both strengthening schemes (side bonded and u-wrapped) exhibited similar behavior, suggesting that the excellent bond of the FRCM to concrete may not require u-wrapped applications for anchorage. The experimental results were also compared with theoretical predictions according to fiber-reinforced polymer (FRP) design guidelines in North America with s...

FRCM Strengthening of Shear-Critical RC Beams

In this paper, an attempt has been made to review various types of shear connector in composite structures. This review tries to identify the shear connectors that are most relevant to composite structures and reviews representative journal publications that are related to this topic. It attempts to cover all types of shear connector. The article concludes with a discussion of recent applications of shear connectors in composite structures. Comparative studies, which have been conducted by several researchers, were covered to address the applicability and the efficiency of various shear connectors. The representative shear connectors for stud connectors as commonly used shear connectors in composite structures were discussed and a summary of their behaviour was included.

	 

	Key words: Shear connector, composite beam, headed studs, perfobond ribs, T-rib connector, oscillating perfobondstrips, waveform strips, channel connector, pyramidal shear connectors, non-welded connectors, INSA HILTI shear connector, rectangular-shaped collar connectors.

https://www.academicjournals.org/article/article1380548506_Shariati et al.pdf

Various types of shear connectors in composite structures: A review

Shear strengthening of reinforced concrete beam using natural fibre reinforced polymer laminates

The aim of the present study is to review the performance of plate bonded flexurally strengthened reinforced concrete beams. This paper also describes the methods and materials used for flexural and shear strengthening of reinforced concrete beams and weaknesses of plate bonded systems. The plate bonding method often has some serious premature debonding failure which can be classified as plate end debonding (end peeling), tension delamination and premature shear failure due to insufficient shear reinforcement. Premature failures must be prevented in order to utilize the full flexural capacity of flexural strengthened reinforced concrete beams. Premature shear failure is one of the major concerns of the flexurally strengthened reinforced concrete (RC) beams. Hence, proper design of external shear strengthening system is required for eliminating premature shear failure of flexurally strengthened RC beams. The review focuses on the possible model and design guideline available in the literature for eliminating premature failures. The paper also discusses a probable approach to eliminate premature shear.

http://eprints.um.edu.my/5971/1/Premature_failures_in_plate_bonded_strengthened_RC_beams_with_an_emphasis_on_premature_shear_A_review.pdf

Premature failures in plate bonded strengthened RC beams with an emphasis on premature shear: A review

Fabrication of green fibre composite laminate for strengthening of reinforced concrete structure is one of the current interests in the field of construction industry. The aim of this research was to develop kenaf fibre reinforced polymer (KFRP) laminate for shear strengthening of reinforced concrete beam. Comprehensive design and theoretical models were also proposed for KFRP laminate shear strengthened beam. In the experimental programme, KFRP laminate had been fabricated with various fibre content to obtain optimal mix ratio. Physical and mechanical properties of KFRP laminates were experimentally investigated. Three reinforced concrete beam specimens were prepared for structural investigations. Results showed that KFRP laminate with maximum fibre content had the highest tensile strength and the laminate was found to be elastic isotropic in nature. The KFRP laminate strengthened beam had 100 % higher shear crack load and 33 % ultimate failure load as compared to un-strengthened control beam. It reduced the numbers and width of cracks and had shown strain compatibility behavior with shear reinforcement. The failure load, ductility, crack patterns and strain characteristics of KFRP laminate strengthened beam were found to be closely comparable with CFRP laminate strengthened beam. The experimental results satisfactorily verified the proposed design and theoretical models.

Development of kenaf fibre reinforced polymer laminate for shear strengthening of reinforced concrete beam

End anchors have been shown to significantly reduce premature plate end debonding failure of plate bonded strengthened reinforced concrete (r. c.) beams. One of the main interest in designing end anchors is to determine the minimum or optimal length of end anchors for a given thickness and height of the end anchor. This paper presents experimental and numerical studies in determining those optimum lengths for steel plate and carbon fibre reinforced polymer (CFRP) laminate flexurally strengthened r. c. beams. In the experimental programme, seven r. c. beams were cast. One beam was tested in the un-strengthened condition to act as the control beam. Three beams were strengthened with steel plates and another three beams were strengthened with CFRP laminates. From each group of the strengthened beams, one beam was strengthened without any end anchor, one was end anchored using the optimum anchorage length and the last one was end anchored using an arbitrarily 200 mm anchorage length. The optimum length for the end anchor used in this study was derived from analyzing the interfacial stress diagram of the strengthened beams and was found to be approximately 100 mm. The beams were also modelled using FEM (LUSAS). The results indicate that the optimized 100 mm anchorage length plates were able to prevent premature plate end debonding failure of steel plate and CFRP laminate strengthened beams satisfactorily. It could also be seen from the results that beams with end anchors had a higher failure loads and had more ductile behaviour than the un-anchored strengthened beams. Results also show that the optimized end anchored strengthened beams had identical structural behaviour to that of the longer end anchored strengthened beams. The numerical results are able to predict the behaviour of the beams satisfactorily.

	 

	Key words: Premature debonding, end peeling, CFRP laminate, steel plate, end anchors.

https://www.africaneditors.org/journal/IJPS/full-text-pdf/48528-116213

Experimental and numerical analysis of end anchored steel plate and CFRP laminate flexurally strengthened r. c. beams

Although a great deal of research has been carried out on simply supported reinforced concrete (RC) beams strengthened with Fibre-Reinforced Polymer composites (FRP), a few works has been focused on continuous beams. Particularly, experiments on strengthening the negative moment regions of continuous T beams are rare to find. This paper reviews 40 articles on CFRP strengthened RC beams and 6 articles on CFRP strengthened RC slabs. Existing 10 articles on CFRP strengthened RC continuous beams are critically reviewed. Finally, this paper attempts to address an important practical issue that is encountered in strengthening the negative moment region of RC continuous T beam. The negative moment region of continuous RC T beam is a critical region due to the concurrence of maximum moment and shear as well as installation restraint due to the presence of column .This paper also proposes a simple method of applying CFRP for strengthening the negative moment region of continuous T beam.

http://eprints.um.edu.my/6004/1/Jumaat_et_al.pdf

Md. Ashraful Alam

Papers

Shear strengthening of reinforced concrete beam using natural fibre reinforced polymer laminates

Premature failures in plate bonded strengthened RC beams with an emphasis on premature shear: A review

Development of kenaf fibre reinforced polymer laminate for shear strengthening of reinforced concrete beam

Experimental and numerical analysis of end anchored steel plate and CFRP laminate flexurally strengthened r. c. beams

Flexural strengthening of RC continuous T beam using CFRP laminate: A review