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Article
Publication date: 1 February 2021

Chrysoula Pandelidi, Tobias Maconachie, Stuart Bateman, Ingomar Kelbassa, Sebastian Piegert, Martin Leary and Milan Brandt

Fused deposition modelling (FDM) is increasingly being explored as a commercial fabrication method due to its ability to produce net or near-net shape parts directly from…

Abstract

Purpose

Fused deposition modelling (FDM) is increasingly being explored as a commercial fabrication method due to its ability to produce net or near-net shape parts directly from a computer-aided design model. Other benefits of technology compared to conventional manufacturing include lower cost for short runs, reduced product lead times and rapid product design. High-performance polymers such as polyetherimide, have the potential for FDM fabrication and their high-temperature capabilities provide the potential of expanding the applications of FDM parts in automotive and aerospace industries. However, their relatively high glass transition temperature (215 °C) causes challenges during manufacturing due to the requirement of high-temperature build chambers and controlled cooling rates. The purpose of this study is to investigate the mechanical properties of ULTEM 1010, an unfilled polyetherimide grade.

Design/methodology/approach

In this research, mechanical properties were evaluated through tensile and flexural tests. Analysis of variance was used to determine the significance of process parameters to the mechanical properties of the specimens, their main effects and interactions. The fractured surfaces were analysed by scanning electron microscopy and optical microscopy and porosity was assessed by X-ray microcomputed tomography.

Findings

A range of mean tensile and flexural strengths, 60–94 MPa and 62–151 MPa, respectively, were obtained highlighting the dependence of performance on process parameters and their interactions. The specimens were found to fracture in a brittle manner. The porosity of tensile samples was measured between 0.18% and 1.09% and that of flexural samples between 0.14% and 1.24% depending on the process parameters. The percentage porosity was found to not directly correlate with mechanical performance, rather the location of those pores in the sample.

Originality/value

This analysis quantifies the significance of the effect of each of the examined process parameters has on the mechanical performance of FDM-fabricated specimens. Further, it provides a better understanding of the effect process parameters and their interactions have on the mechanical properties and porosity of FDM-fabricated polyetherimide specimens. Additionally, the fracture surface of the tested specimens is qualitatively assessed.

Details

Rapid Prototyping Journal, vol. 27 no. 2
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 5 April 2011

Colin Williams, Steve Goodhew and Richard Griffiths

The purpose of the paper is to explore the structural feasibility of substituting traditional thick joint mortars with earth slurry mortars modified with varying amounts…

Abstract

Purpose

The purpose of the paper is to explore the structural feasibility of substituting traditional thick joint mortars with earth slurry mortars modified with varying amounts of sand. Thin jointing of earth blocks would reduce the cost of sustainable earth construction.

Design/methodology/approach

Compressive strength of earth‐block cubes was determined. Flexural strength was measured using the BRE electronic bond wrench, which enables block couplets to be tested quickly and accurately. Three samples of earth block, one from southwest England and two from East Anglia, together with nine examples of earth slurry mortar jointing were studied, including the effect of reinforcing the joint and or the block using hessian.

Findings

The 28‐day cube characteristic compressive strengths were determined for Appley soil, Norfolk lump and Beeston soil, the last with 0 per cent sand, 25 per cent sand and with 25 per cent sand with hessian. The flexural strengths of Appley and Beeston earth slurries were determined, along with Thermalite thin jointed cement and cement mortar for comparison. The Beeston soil flexural strength increased with increasing sand content. Earth slurry with 40 per cent sand and hessian present in the joint gave the greatest strength. It is important to use blocks and slurry mortars of the same soil. Extruded and compressed earth blocks are best suited to slurry jointing.

Originality/value

This work successfully demonstrates the structural feasibility of carefully reducing the thickness of earth mortars when constructing sustainable earth block walling. Characteristic flexural strengths are suggested where the test results were sufficiently consistent, and of a magnitude likely to be useful in design.

Details

Structural Survey, vol. 29 no. 1
Type: Research Article
ISSN: 0263-080X

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Article
Publication date: 10 June 2019

Rajendra Kumar, Ravi Pratap Singh and Ravinder Kataria

This paper aims to investigate the flexural properties i.e. the flexural strength and the flexural modulus under the influence of selected input variables, namely; fiber…

Abstract

Purpose

This paper aims to investigate the flexural properties i.e. the flexural strength and the flexural modulus under the influence of selected input variables, namely; fiber type, fiber loading and fiber size in fabricated natural fiber polymeric composites through using Taguchi’s design of experiment methodology.

Design/methodology/approach

The Taguchi’s design of experiment approach has been used to scheme a suitable combination to fabricate the polymeric composites. Pure polypropylene (PP) has been chosen as a matrix material, whereas two types of fibers, namely; wood powder (WP) i.e. sawdust and rice husk powder (RHP), have been used as a reinforcement in the matrix. Microstructure analysis of fabricated and tested samples has also been evaluated and analyzed using a scanning electron microscope. This analysis has divulged that at moderate fiber size and higher fiber loading, no gap or cavities presented between the fillers and matrix particles, which illustrates the good interfacial bonding between the materials.

Findings

The flexural strength of the wood powder pure polypropylene (WPPP) composite decreases if the fiber content gets increased beyond 20 Wt.%. In addition, the flexural strength of hybrid composite (WPRHPPP) has been revealed to get improved more in comparison to composites with single fiber as reinforcement. Furthermore, the flexural modulus of WPPP composite has also increased with the increase in fiber loading. It has been concluded that reinforcement size plays an imperative role in influencing the flexural modulus. The optimum parametric setting for the flexural strength and the flexural modulus has been devised as; fiber type – WPRHP, fiber loading – 10 Wt.% and fiber size – 600 µm; and fiber type – WP, fiber loading – 30 Wt.% and fiber size – 1,180 µm, respectively. The microstructure images clearly revealed that during conducted flexural tests, some particles get disturbed from their bonded position that mainly represents the plastic deformation.

Social implications

The fabricated polymer materials proposed in the research work are green and environmentally friendly.

Originality/value

The natural fiber-based composites are possessing wide-spread requirements in today’s competitive structure of manufacturing and industrial applications. The fabrication of the natural fiber-based composites has also been planned through the designed experiments (namely; Taguchi Methodology- L9 orthogonal array matrix), which, further, makes the analysis more fruitful and qualitative too. The fabricated polymer materials proposed in the research work are green and environmentally friendly. Shisham WP has been rarely used in the past researches; therefore, this factor has been included for the present work. The injection molding process is used to fabricate the three different polymer composite by varying the fiber weight percentage and fiber size.

Details

World Journal of Engineering, vol. 16 no. 3
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 3 January 2017

Shamsad Ahmad

This study aims to make an effort to develop a model to predict the residual flexural strength of reinforced concrete beams subjected to reinforcement corrosion.

Abstract

Purpose

This study aims to make an effort to develop a model to predict the residual flexural strength of reinforced concrete beams subjected to reinforcement corrosion.

Design/methodology/approach

For generating the required data to develop the model, a set of experimental variables was considered that included corrosion current density, corrosion duration, rebar diameter and thickness of concrete cover. A total of 28 sets of reinforced concrete beams of size 150 × 150 × 1,100 mm were cast, of which 4 sets of un-corroded beams were tested in four-point bend test as control beams and the remaining 24 sets of beams were subjected to accelerated rebar corrosion inducing different levels of corrosion current densities for different durations. Corroded beams were also tested in flexure, and test results of un-corroded and corroded beams were utilized to obtain an empirical model for estimating the residual flexural strength of beams for given corrosion current density, corrosion duration and diameter of the rebars.

Findings

Comparison of the residual flexural strengths measured experimentally for a set of corroded beams, reported in literature, with that predicted using the model proposed in this study indicates that the proposed model has a reasonably good accuracy.

Originality/value

The empirical model obtained under this work can be used as a simple tool to predict residual flexural strength of corroded beams using the input data that include rebar corrosion rate, corrosion duration after initiation and diameter of rebars.

Details

Anti-Corrosion Methods and Materials, vol. 64 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 11 June 2018

Hassan A.M. Mhamoud and Jia Yanmin

This study aims to investigate the effectiveness of different additives (individual effects) in improving the strength of concrete to resist temperatures of up to 60ºC.

Abstract

Purpose

This study aims to investigate the effectiveness of different additives (individual effects) in improving the strength of concrete to resist temperatures of up to 60ºC.

Design/methodology/approach

In all, 13 different mixtures with a constant water/binder ratio of 0.36 and grade M40 were prepared by using ordinary Portland concrete alone, or with partial replacement by fly ash (FA), blast-furnace slag, silica fume (SF) and a combination of all three. After 7 and 28 days under water, their strength and residual strength were measured.

Findings

The results of testing revealed that the addition of 10 per cent SF was found to result in the greatest increase in compressive strength and flexural strength along with decreased the residual strengths. The addition of FA increased the compressive strength and enhanced the residual compressive strength. However, it also decreased the residual flexural strength.

Originality/value

The addition of slag achieved better flexural strength and the best residual compressive strength. The combination of additives also enhanced the compressive strength but was not found to be better than using SF alone.

Details

Journal of Structural Fire Engineering, vol. 9 no. 2
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 13 February 2020

Ghasem Pachideh and Majid Gholhaki

With respect to the studies conducted so far and lack of researches on the post-heat behavior of cement mortars containing pozzolanic materials, the purpose of this paper…

Abstract

Purpose

With respect to the studies conducted so far and lack of researches on the post-heat behavior of cement mortars containing pozzolanic materials, the purpose of this paper is to investigate the post-heat mechanical characteristics (i.e. compressive, tensile and flexural strength) of cement mortars containing granulated blast-furnace slag (GBFS) and silica fume (SF). In doing so, selected temperatures include 25, 100, 250, 500, 700 and 9000c. Last, the X-ray diffraction test was conducted to study the microstructure of mixtures and subsequently, the results were presented as power-one mathematical relations.

Design/methodology/approach

Totally, 378 specimens were built to conduct flexural, compressive and tensile strength tests. Accordingly, these specimens include cubic and prismatic specimens with dimensions of 5 × 5 × 5 cm and 16 × 4 × 4 cm, respectively, to conduct compressive and flexural strength tests together with briquette specimen used for tensile strength test in which cement was replaced by 7, 14 and 21 per cent of SF and GBFS. To study the effect of temperature, the specimens were heated. In this respect, they were heated with a rate of 5°C/min and exposed to temperatures of 25 (ordinary temperature), 100, 250, 500, 700 and 900°C.

Findings

On the basis of the results, the most profound effect of using GBFS and SF, respectively, takes place in low (up to 250°C) and high (500°C and greater degrees) temperatures. Quantitatively, the compressive, tensile and flexural strengths were enhanced by 73 and 180 per cent, 45 and 100 per cent, 106 and 112 per cent, respectively, in low and high temperatures. In addition, as the temperature elevates, the particles of specimens containing SF and GBFS shrink less in size compared to the reference specimen.

Originality/value

The specimens were cured according to ASTMC192 after 28 days placement in the water basin. First, in compliance with what has been specified by the mix design, the mortar, including pozzolanic materials and superplasticizer, was prepared and then, the sampling procedure was conducted on cubic specimens with dimension of 5 × 5 × 5 mm for compressive strength test, prismatic specimens with dimensions of 16 × 4 × 4 mm for flexural strength test and last, briquette specimens were provided to conduct tensile strength tests (for each temperature and every test, three specimens were built).

Details

Journal of Structural Fire Engineering, vol. 11 no. 2
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 10 August 2019

Daniel Paul Thanaraj, Anand N. and Prince Arulraj

This paper aims to explain the influence of Standard Fire as per ISO 834 on the strength and microstructure properties of concrete specimens with different strength grade.

Abstract

Purpose

This paper aims to explain the influence of Standard Fire as per ISO 834 on the strength and microstructure properties of concrete specimens with different strength grade.

Design/methodology/approach

The strength grades of concrete considered for the experimental investigation were Fck20, Fck30, Fck40 and Fck50. The specimens were heated up to 1, 2, 3 and 4 h as per standard fire curve. Effect of elevated temperature on compressive and flexural behavior of specimens with various strength grades was examined. Effects of age of concrete, weight loss, surface characteristics and thermal crack pattern were also investigated.

Findings

Experimental investigation shows that strength grade, duration of exposure and age of concrete are the key parameters affecting the residual strength of concrete. For the beams exposed to 3 and 4 h of heating, the residual flexural strength was found to be so insignificant that the specimens were not able to even sustain their own weight. The loss in compressive and flexural strength of Fck50 concrete specimens heated up to 1 h were found to be 26.41 and 86.03 per cent of the original unheated concrete, respectively. The weight loss was found to be more for higher grade concrete specimens, and it was about 8.38 per cent for Fck50 concrete. Regression analysis was carried out to establish the empirical relation between residual strength and grade of concrete. Scanning electron microscopy and thermogravimetric analysis were carried out to examine the damage level of fire-affected concrete specimens.

Originality/value

Empirical relationship was developed to determine the residual strength of concrete exposed to elevate temperature, and this will be useful for design applications. This database may be useful for identifying member strength of reinforced beams subjected to various durations of heating so that suitable repair technique can be adopted from the available database. It will be useful to identify the proper grade of concrete with regard to fire endurance, in the case of concrete under compression or flexure.

Details

Journal of Engineering, Design and Technology , vol. 17 no. 5
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 8 April 2019

M. Ramesh, C. Deepa, G.R. Arpitha and V. Gopinath

In the recent years, the industries show interest in natural and synthetic fibre-reinforced hybrid composites due to weight reduction and environmental reasons. The…

Abstract

Purpose

In the recent years, the industries show interest in natural and synthetic fibre-reinforced hybrid composites due to weight reduction and environmental reasons. The purpose of this experimental study is to investigate the properties of the hybrid composites fabricated by using carbon, untreated and alkaline-treated hemp fibres.

Design/methodology/approach

The composites were tested for strengths under tensile, flexural, impact and shear loadings, and the water absorption characteristics were also observed. The finite element analysis (FEA) was carried out to analyse the elastic behaviour of the composites and predict the strength by using ANSYS 15.0.

Findings

From the experimental results, it is observed that the hybrid composites can withstand the maximum tensile strength of 61.4 MPa, flexural strength of 122.4 MPa, impact strength of 4.2 J/mm2 and shear strength of 25.5 MPa. From the FEA results, it is found that the maximum stress during tensile, flexural and impact loading is 47.5, 2.1 and 1.03 MPa, respectively.

Originality/value

The results of the untreated and alkaline-treated hemp-carbon fibre composites were compared and found that the alkaline-treated composites perform better in terms of mechanical properties. Then, the ANSYS-predicted values were compared with the experimental results, and it was found that there is a high correlation occurs between the untreated and alkali-treated hemp-carbon fibre composites. The internal structure of the broken surfaces of the composite samples was analysed using a scanning electron microscopy (SEM) analysis.

Details

World Journal of Engineering, vol. 16 no. 2
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 12 October 2010

S. Ghanbarpour, H. Mazaheripour, S.H. Mirmoradi and A. Barari

Self‐compacting concrete (SCC) offers several economic and technical benefits; the use of steel fibers extends its possibilities. Steel fibers bridge cracks, retard their…

Abstract

Purpose

Self‐compacting concrete (SCC) offers several economic and technical benefits; the use of steel fibers extends its possibilities. Steel fibers bridge cracks, retard their propagation, and improve several characteristics and properties of the SCC. The purpose of this paper is to investigate the effects of type and volume fraction of steel fiber on the compressive strength, split tensile strength, flexural strength and modulus of elasticity of steel fiber reinforced self‐compacting concrete (SFRSCC).

Design/methodology/approach

For this purpose, Micro wire and Wave type steel fibers with l/d ratios of 50 were used. Three different fiber volumes were added to concrete mixes at 0.5, 0.75 and 1 per cent by volume of SCC. Six different SFRSCC mixes were prepared. After 28 days of curing, compressive, split and flexural strength and modulus of elasticity were determined.

Findings

It was found that, inclusion of steel fibers significantly affect the split tensile and flexural strength of SCC accordance with type and vf. Besides, mathematical expressions were developed to estimate the flexural, modulus of elasticity and split tensile strength of SFRSCCs regarding of compressive strength.

Originality/value

It was found that inclusion of steel fibers significantly affected the split tensile and flexural strength of SCC accordance with type and f v.

Details

Journal of Engineering, Design and Technology, vol. 8 no. 3
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 11 December 2017

Hassan A.M. Mhamoud and Jia Yanmin

This study aims to focus on the resistance to elevated temperatures of up to 700ºC of high-performance concrete (HPC) compared to ordinary Portland concrete (OPC) with…

Abstract

Purpose

This study aims to focus on the resistance to elevated temperatures of up to 700ºC of high-performance concrete (HPC) compared to ordinary Portland concrete (OPC) with regards to mass loss and residual compressive and flexural strength.

Design/methodology/approach

Two mixtures were developed to test. The first mixture, OPC, was used as the control, and the second mixture was HPC. After 28 days under water (per Chinese standard), the samples were tested for compressive strength and residual strength.

Findings

The test results showed that at elevated temperatures of up to 500ºC, each mixture experienced mass loss. Below this temperature, the strength and the mass loss did not differ greatly.

Originality/value

When adding a 10 per cent silica fume, 25 per cent fly, 25 per cent slag to HPC, the compressive strength increased by 17 per cent and enhanced the residual compressive strength. A sharp decrease was observed in the residual flexural strength of HPC when compared to OPC after exposure to temperatures of 700ºC.

Details

Journal of Structural Fire Engineering, vol. 8 no. 4
Type: Research Article
ISSN: 2040-2317

Keywords

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