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Article
Publication date: 13 May 2020

Essam Mossalam, Nivin M. Ahmed, Eglal M.R. Souaya and Basil El-Sabbagh

The purpose of this research is to study the physical and mechanical properties beside the durability of concrete as well as corrosion resistance of reinforced concrete by…

Abstract

Purpose

The purpose of this research is to study the physical and mechanical properties beside the durability of concrete as well as corrosion resistance of reinforced concrete by replacing Ordinary Portland cement (OPC) with different ratios of silica fume and meta-kaolin and applying two paint formulations to enhance corrosion resistance and mechanical properties. In this work, modified concrete mixes containing pozzolanic materials of industrial wastes such as silica fume (SF) with ratios ranging between (0, 10 and 15%) and calcined raw material such as meta-kaolin (MK) with ratios (0, 3, 5 and 10%), were introduced using water binder ratio (w/b) 0.45 to study their effect on the physico-mechanical properties and durability of concrete as well as corrosion protection performance of reinforced concrete. Two paint formulations containing the same ingredients except that one of them is free from talc (G1) and the other contains talc (G2) were applied on the rebars embedded in these modified mixes. Talc is known to offer high pH to the surrounding media.

Design/methodology/approach

Modified concrete mixes containing the coated reinforced concrete steel with the different paint formulations in presence and absence of talc were tested, and the corrosion behavior was studied using electrochemical impedance spectroscopy (EIS) in 3.5% NaCl, and the concrete mixes were also tested through their compressive strength, chloride permeability, scanning electron microscope/energy dispersive X-ray analysis and bond strength.

Findings

The results revealed that the hardened reinforced concrete mix containing 10% SF with 5% MK with embedded rebars coated with G2 (paint containing talc) was the best concrete system which offers concrete sustainability besides high corrosion protection performance, i.e. presence of talc in the paints combined with the effect of cement blended with SF and MK showed positive effect on the reinforced concrete properties that leads to more durability and workability.

Originality/value

The integrity of using two efficient methods of corrosion protection beside the effect of the different replacements in concrete mixes containing coated reinforced concrete steel with paint formulations free from talc (G1) and others containing talc (G2), which lead to fatal changes in the pH of the surrounding media (i.e. concrete which has high alkaline pH) to achieve good concrete properties aside with convenient paint formulations together.

Details

Pigment & Resin Technology, vol. 50 no. 1
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 1 August 2001

S. Choi, T.R. Bieler, K.N. Subramanian and J.P. Lucas

Eutectic Sn‐Ag solder is being considered as a potential replacement for Sn‐Pb solders. A potential drawback to using the eutectic Sn‐Ag solder is its higher melting…

Abstract

Eutectic Sn‐Ag solder is being considered as a potential replacement for Sn‐Pb solders. A potential drawback to using the eutectic Sn‐Ag solder is its higher melting point, 221°C, compared with the eutectic Pb‐Sn solder. Owing to its higher melting temperature, the eutectic Sn‐Ag solder is also being considered for automotive under‐the‐hood applications, which experience high temperature environments. Electronic components and/or circuit boards are often coated with Pb‐bearing solder to facilitate soldering operations. Soldering Pb‐bearing solder coated components and/or boards with eutectic Sn‐Ag solder will result in joints contaminated with Pb. In this study, the effects of Pb contamination on eutectic Sn‐Ag solder joints were investigated using three ternary alloys made by incorporating some Pb into eutectic Sn‐Ag solder. These ternary alloys all showed a peak at 178°C in heating curves obtained using Differential Scanning Calorimetry (DSC), which resulted from the ternary eutectic composition in the Sn‐Ag‐Pb system. The Pb phases in the ternary alloys were found to be dispersed throughout the microstructure. A practical implication of Pb contamination in eutectic Sn‐Ag solder joints is that the service temperature of such joints would be limited by the lower melting temperature of the ternary eutectic phase.

Details

Soldering & Surface Mount Technology, vol. 13 no. 2
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 30 September 2014

Samuel Olufemi Folagbade and Moray David Newlands

This paper aims to assess the suitability of cement combination containing CEM I, fly ash, silica fume and metakaolin for durability design against carbonation-induced…

Abstract

Purpose

This paper aims to assess the suitability of cement combination containing CEM I, fly ash, silica fume and metakaolin for durability design against carbonation-induced corrosion in concrete.

Design/methodology/approach

Cube compressive strengths at 28 days and accelerated carbonation depths at 28 days and at various exposure ages were determined at the water/cement ratios of 0.35, 0.50 and 0.65. To assess their suitability for carbonation-induced corrosion, the material costs and embodied carbon dioxide (eCO2) contents of the concretes at equivalent performance were compared.

Findings

Cement combination concretes achieved equal carbonation resistance with CEM I at higher compressive strengths, lower water/cement ratios and higher cement contents. The comparison of the concretes, at equivalent performance, based on the carbonation-induced corrosion exposure classes XC3 and XC4 (Table A.4 of BS 8500-1), shows that ternary and more binary cement concretes have lower costs and eCO2 contents than those recommended in Table A.6 of BS 8500-1.

Research limitations/implications

This analysis is limited to a working life of 50 years. Further research is needed to verify the suitability of the cement combinations for a working life of 100 years and for the other aspects of durability design covered in BS 8500.

Practical implications

Cement combination concretes have lower eCO2 content. Hence, when they are cheaper than CEM I concrete at equivalent performance, they would make concrete construction more economic and environmentally compatible.

Originality/value

This research suggests the inclusion of metakaolin and ternary cement combination concretes in BS 8500 for durability design against carbonation-induced corrosion.

Details

Journal of Engineering, Design and Technology, vol. 12 no. 4
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 1 April 2003

Marc Dittes and Hermann Walter

A new alloy for lead‐free solder balls is introduced combining the advantages of a smooth surface after production and a uniform reflectivity after the ball attach…

Abstract

A new alloy for lead‐free solder balls is introduced combining the advantages of a smooth surface after production and a uniform reflectivity after the ball attach process. This property significantly simplifies the inspection process during ball grid array (BGA) processing. By adding small amounts of Indium and Lanthanum to the ternary eutectic SnAgCu‐alloy a pentary, virtually eutectic composition with a melting point of 214°C is realised. It is shown that the processability in terms of reflow behaviour and the shear strength of BGA spheres made of this alloy is comparable to or better than that of ternary SnAgCu‐balls.

Details

Soldering & Surface Mount Technology, vol. 15 no. 1
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 3 March 2020

Yacine Abadou, Abderrahmane Ghrieb, Rosa Bustamante and Hayette Faid

The purpose of this study is to fit an appropriate mathematical model to express response variables as functions of the proportions of the mixture components. One purpose…

Abstract

Purpose

The purpose of this study is to fit an appropriate mathematical model to express response variables as functions of the proportions of the mixture components. One purpose of statistical modeling in a mixture experiment is to model the blending surface such that predictions of the response for any mixture component, singly or in combination, can be made empirically. Testing of the model adequacy will also be an important part of the statistical procedure.

Design/methodology/approach

A series of mortar using air lime, marble and ceramic sanitary waste aggregates were prepared for statistically designed combinations. The combinations were designed based on the mixture-design concept of design of experiments; this mortar is often used as a filler material in restoration projects. The aim of this work is to find an optimal composition of a paste for the manufacture of air lime mortar with ceramic and marble waste. This investigation aims to recommend mix design for air lime-based mortar, by optimizing the input combination for different properties, and to predict properties such as mechanical strength, thermogravimetric and x-ray diffraction analysis with a high degree of accuracy, based on a statistical analysis of experimental data.

Findings

This paper discusses those mortar properties that architects, contractors and owners consider important. For each of these properties, the influence of ceramic and marble waste in the air lime mortar is explored. The flexibility of lime-based mortars with waste materials to meet a wide range of needs in both new construction and restoration of masonry projects is demonstrated.

Originality/value

The objective of the present investigation is to recommend mixture design for air lime mortar with waste, by optimizing the input combination for different properties, and to predict properties such as compressive strength, flexural strength with a high degree of accuracy, based on the statistical analysis of experimental data. The authors conducted a mixture design study that takes into account dependent parameters such as the constituents of our air lime-based mortar where we have determined an experiment matrix to which we have connected the two responses, namely, compressive and flexural strength. By introducing the desirability criteria of these two responses, using JMP software, we were able to obtain a mixture optimal for air lime mortar with ceramic and marble waste.

Details

Journal of Engineering, Design and Technology , vol. 18 no. 6
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 19 September 2008

M. Reid, J. Punch, M. Collins and C. Ryan

The purpose of this paper is to examine the microstructure and evaluate the intermetallic compounds in the following lead‐free solder alloys: Sn98.5Ag1.0Cu0.5 (SAC105) Sn…

Abstract

Purpose

The purpose of this paper is to examine the microstructure and evaluate the intermetallic compounds in the following lead‐free solder alloys: Sn98.5Ag1.0Cu0.5 (SAC105) Sn97.5Ag2.0Cu0.5 (SAC205) Sn96.5Ag3.0Cu0.5 (SAC305) and Sn95.5Ag4.0Cu0.5 (SAC405).

Design/methodology/approach

X‐ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to identify the main intermetallics formed during solidification. Differential scanning calorimetry (DSC) was used to investigate the undercooling properties of each of the alloys.

Findings

By using XRD analysis in addition to energy dispersive spectroscopy (EDS) it was found that the main intermetallics were Cu6Sn5 and Ag3Sn in a Sn matrix. Plate‐like ε‐Ag3Sn intermetallics were observed for all four alloys. Solder alloys SAC105, SAC205 and SAC305 showed a similar microstructure, while SAC405 displayed a fine microstructure with intermetallic phases dense within the Sn matrix.

Originality/value

Currently, low‐silver content SAC alloys are being investigated due to their lower cost, however, the overall reliability of an alloy can be greatly affected by the microstructure and this should be taken into consideration when choosing an alloy. The size and number of Ag3Sn plate‐like intermetallics can affect the reliability as they act as a site for crack propagation.

Details

Soldering & Surface Mount Technology, vol. 20 no. 4
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 5 May 2020

Niragi Dave, Vaishali Sahu and Anil Kumar Misra

The purpose of this work is to study the in-situ performance of ternary geopolymer concrete in road repair work. Geopolymer cement concrete is an attractive alternative to…

Abstract

Purpose

The purpose of this work is to study the in-situ performance of ternary geopolymer concrete in road repair work. Geopolymer cement concrete is an attractive alternative to Portland cement concrete owing to environmental, economic and performance benefits. Industrial wastes, such as fly ash (FA) and ground granular blast furnace slag (GGBS), have been extensively used to manufacture unitary and binary geopolymer concrete with heat activation (at different temperature); however, it has indicated a limitation for its application in precast industry only.

Design/methodology/approach

In the present study, efforts have been made to produce a ternary geopolymer concrete mix, using GGBS, FA and Silica fumes (SF) in varied proportion mixed with 8 M sodium hydroxide (NaOH) as alkali activator and cured at ambient temperature. Total ten geopolymer concrete mixes have been prepared and tested for strength and durability properties and compared with control mix of ordinary Portland cement (OPC). Based on the mechanical properties of various mixes, an optimum geopolymer concrete mix has been identified. The control mix and optimum geopolymer have been studied for microstructural properties through scanning electron microscopy.

Findings

The in situ performance of the optimum mix has been assessed when used as a road repair material on a stretch of road. The ternary geopolymer concrete mixes (a) 65% GGBS + 25% FA + 10% SF, (b) 70% GGBS + 20% FA + 10% SF, and (c) 75% GGBS + 15% FA + 10% SF have resulted in good strength at ambient temperature and the mix 75% GGBS + 15% FA + 10% SF have shown good in situ performance when tested for road repair work.

Originality/value

Geopolymer concrete is gaining interest in many fields as an alternative to conventional concrete, as it not only reduces carbon footprint due to huge cement production but also provides a sustainable disposal method for many industrial wastes. This paper focuses on finding some alternative of OPC concrete to reduce dependency on the OPC.

Details

Journal of Engineering, Design and Technology , vol. 18 no. 5
Type: Research Article
ISSN: 1726-0531

Keywords

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Article
Publication date: 1 May 2005

Eric Pardede, J. Wendy Rahayu and David Taniar

Despite the increasing demand for an effective XML document repository, many are still reluctant to store XML documents in their natural tree form. One main reason is the…

Abstract

Despite the increasing demand for an effective XML document repository, many are still reluctant to store XML documents in their natural tree form. One main reason is the inadequacy of XML query languages to update the tree‐form XML documents. Even though some of the languages have supported minimum update facilities, they do not concern on preserving the documents constraints. The results are updated documents with very low database integrity. In this paper, we propose a methodology to accommodate XML Update without violating the conceptual constraints of the documents. The method takes form as a set of functions that perform checking mechanisms before update operations. In this paper we discuss the conceptual constraints embedded in three different relationship structures: association, aggregation and inheritance relationship. We highlight four constraints related with association relationship (nuber of participants, referential integrity, cardinality, and adhesion), five constraints related with aggregation relationship (cardinality, adhesion, ordering, homogeneity and share‐ability) and two constraints related to inheritance relationship (disjoint and number of super‐class). In addition, a specific constraint, which is collection type of children, will also be discussed. The proposed method can be implemented in different ways, for example in this paper we use XQuery language. Since the XML update requires schema, in this paper we also propose the mapping of the these constraints in the conceptual level to the XML Schema. We use XML Schema for structure validation, even though the algorithm can be used by any schema languages.

Details

International Journal of Web Information Systems, vol. 1 no. 2
Type: Research Article
ISSN: 1744-0084

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Article
Publication date: 29 November 2018

Simbarashe Fashu and Rajwali Khan

Thin coatings are of great importance to minimize corrosion attack of steel in different environments. A review of recent work on electrodeposition and corrosion…

Abstract

Purpose

Thin coatings are of great importance to minimize corrosion attack of steel in different environments. A review of recent work on electrodeposition and corrosion performance of Zn-Ni-based alloys for sacrificial corrosion protection of ferrous substrates is presented. The purpose of this study is to provide a systematic comparison of the corrosion resistances of Zn-Ni alloy coatings. The review contains key and outstanding comparisons of references for the period from 2007 to 2017. Binary and ternary Zn-Ni-based alloys were compared and contrasted to provide a good knowledge basis for selection of best coating system to steel substrates.

Design/methodology/approach

This article is a review article.

Findings

Zn-Ni-(X) alloys show great potential for replacing Cd metal in corrosion protection of steel substrates.

Practical implications

The research on plating of binary Zn-Ni alloys from aqueous electrolytes is now well advanced and these alloys show improved corrosion resistance compared to pure Zn. Pulse plated and compositionally modulated multilayer Zn-Ni alloy coatings showed enhanced corrosion properties compared to direct plated Zn-Ni coatings of similar composition.

Originality/value

The work on electrodeposition of Zn-Ni based alloys from ionic liquids is still scarce, yet these liquids show great promise in improving corrosion resistance and reducing coating thickness when compared to aqueous electrolytes. Advanced plating techniques in ionic liquids such as electromagnetic, compositionally modulated multilayer, pulse plating, ternary alloys and composites should be considered as these electrolytes avoid water chemistry and associated defects.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 11 April 2021

Tarek Hadji, Salim Guettala and Michèle Quéneudec

The purpose of this paper is to present the modeling of statistical variation of experimental data using the design of experiments method to optimize the formulation of a…

Abstract

Purpose

The purpose of this paper is to present the modeling of statistical variation of experimental data using the design of experiments method to optimize the formulation of a high performance concrete (HPC) using materials that are locally available in Algeria. For this, two mineral additions (natural pozzolana and limestone filler [LF]) were used. Both additions are added by substitution of cement up to 25%. To better appreciate the effect of replacing a part of cement by natural pozzolana and LF and to optimize their combined effect on the characteristics of HPC, an effective analytical method is therefore needed to reach the required objective.

Design/methodology/approach

The experimental part of the study consisted of substituting a portion of cement by various proportions of these additions to assess their effects on the physico-mechanical characteristics of HPC. A mixture design with three factors and five levels was carried out. The JMP7 software was used to provide mathematical models for the statistical variation of measured values and to perform a statistical analysis. These models made it possible to show the contribution of the three factors and their interactions in the variation of the response.

Findings

The mixture design approach made it possible to visualize the influence of LF and pozzolanic filler (PF) on the physico-mechanical characteristics of HPC, the developed models present good correlation coefficients (R2 = 0.82) for all studied responses. The obtained results indicated that it is quite possible to substitute a part of cement with LF and PF in the formulation of a HPC. Thanks to the complementary effect between the two additions, the workability could be improved and the strengths drop could be avoided in the short, medium and long term. The optimization of mixture design factors based on the mathematical models was carried out to select the appropriate factors combinations; a good agreement between the experimental results and the predicted results was obtained.

Originality/value

The coefficient of PF in Cs28 model is closer to that of LF than in Cs7 model, thanks to the complementary effect between LF and PF at the age of 28 days. It was found that the optimal HPC14 concrete (10%LF–5%PF) provides the best compromise between the three responses. It is also worth noting that the use of these two local materials can reduce the manufacturing costs of HPC and reduce carbon dioxide emissions into the atmosphere. This can be an important economic and environmental alternative.

Details

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

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