Taha Hocine Douara, Salim Guettala, Tarek Hadji and Ahmed Attia
The purpose of this study is to contribute with experimental study of the effects of binary and ternary combinations of river sand (RS), crushed sand (CS) and dune sand (DS) on…
Abstract
Purpose
The purpose of this study is to contribute with experimental study of the effects of binary and ternary combinations of river sand (RS), crushed sand (CS) and dune sand (DS) on the physical and mechanical performances of self-compacting concrete (SCC) subjected to acidic curing environments, HCl and H2SO4 solutions.
Design/methodology/approach
Five SCCs were prepared with the combinations 100% RS, 0.8RS + 0.2CS, 0.6RS + 0.2CS + 0.2DS, 0.6RS + 0.4DS and 0.6CS + 0.4DS. The porosity of sand, fluidity, deformability, stability, compressive strength and sorptivity coefficient were tested. SCCs cubic specimens with a side length of 10 cm were submerged in HCl and H2SO4 acids, wherein the concentration was 5%, for periods of 28, 90 and 180 days. The resistance to acid attack was evaluated by visual examination, mass loss and compressive strength loss.
Findings
The results showed that it is possible to partially substitute the RS with CS and DS in the SCC, without strongly affecting the fluidity, deformability, stability, compressive strength and durability against HCl and H2SO4 attack. The two combinations, 0.8RS + 0.2CS and 0.6RS + 0.2CS + 0.2DS, improved the compactness and the resistance to acid attacks of SCC. Consequently, the improvement in SCC compactness, by the combination of RS, CS and DS, decreased the sorptivity coefficient of SCC and increased its resistance to acid attacks, in comparison with that made only by RS.
Originality/value
The use of RS is experiencing a considerable increase in line with the development of the country. To satisfy this demand, it is necessary to substitute this sand with other materials more abundant. The use of locally available materials is a very effective way to protect the environment, improve the physico-mechanical properties and durability of SCC and it can be a beneficial economical alternative. Few studies have addressed the effect of the binary and ternary combination of RS, CS and DS on the resistance to acid attacks of SCC.
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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 high…
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.
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The purpose of this work is to discuss high-strength concrete mix proportioning optimization. In this study, the three parameters (W/B ratio), coarse aggregate maximum size (Dmax…
Abstract
Purpose
The purpose of this work is to discuss high-strength concrete mix proportioning optimization. In this study, the three parameters (W/B ratio), coarse aggregate maximum size (Dmax) and superplasticizer dosage (Sp%) were considered.
Design/methodology/approach
A full factorial design with three factors and two levels was carried out. The statistical analysis and analysis of variance of statistical models were made easier with the aid of JMP7 software. The generated models explain how each parameter affects the mechanical compressive strength at 28 days (Cs28) and slump, and they have an excellent determination coefficient (R2 = 0.99). For each high-strength concrete (HSC) mixture, the slump was measured four times: at 0 min, 20 min, 40 min and 60 min.
Findings
The results show that HSC6 (0.35(W/B), 12.5(Dmax), 1.4(Sp%)) is the best HSC mixture, with a (Cs28) of 71.84 MPa, a slump of 22 cm, and slump loss of 3.5 cm in 60 min.
Originality/value
Quantifying the impact of high-strength concrete mix components from a small number of experiments is made achievable by combining two methods: the Dreux-Gorisse method and the full factorial design approach. It's possible to tune the mix proportioning of the high-strength concrete for the desired slump and compressive mechanical strength thanks to the created statistical models.
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Mahesh Joshi, Monika Kansal and Sharad Sharma
This paper aims to explore the awareness of terminology related to intellectual capital (IC) among executives of Indian banks and the sources in which they mostly find IC-related…
Abstract
Purpose
This paper aims to explore the awareness of terminology related to intellectual capital (IC) among executives of Indian banks and the sources in which they mostly find IC-related terminology. The paper also explores relative and specific contributions of each selected source of information in creating IC awareness among bank executives in India and determines difference among the executives from the public and private sector.
Design/methodology/approach
This research paper follows a survey-based approach to capture the perceptions of Indian bank managers working middle and top management across different banks. Regression analysis and ANOVA were applied to data from 166 responses.
Findings
The study finds that IC awareness among Indian banking executives is reasonably high and is equally spread across the three sub-categories of capital (external capital, human capital and internal capital), though the relative awareness of external capital is on the higher side. However, the sources of awareness of IC terminology differ among executives from the public- and private-sector banks.
Research limitations/implications
The sample was limited to middle and top managers in the Indian banking industry and suffers from the usual limitations of survey-based research such as the design of the survey instrument and the personal biases of the respondents. Some limitations may also have arisen because of the definitions of IC elements adopted by this study.
Originality/value
This research adds a new dimension to the IC research by exploring the practical application and awareness of IC that deviates from traditional annual report-based disclosure and valuation studies. No existing literature has examined the survey-based awareness study, particularly on the banking industry. This paper provides a foundation for future studies that examine the operational awareness and application of IC in the service industries.
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Piyush Sharma, Pasumarti Srinivas Subbarao, Anjali Sane and Jivan Biradar
Gomaa Abdel-Maksoud, Hanaa Nasr, Sayed Hussein Samaha and Mahmoud Saad ELdeen Kassem
This study aims to evaluate the state of preservation of one of the most famous manuscripts dated back to the 15th century using some analytical techniques to identify the…
Abstract
Purpose
This study aims to evaluate the state of preservation of one of the most famous manuscripts dated back to the 15th century using some analytical techniques to identify the manuscript components, explain its deterioration mechanisms and produce some solutions for conservation processes in future studies.
Design/methodology/approach
The analytical techniques used were visual assessment, digital microscope, scanning electron microscope (SEM) with EDX, pH measurement, attenuated total reflection – Fourier transform infrared spectroscopy (ATR/FTIR) and cellulose crystallinity.
Findings
Stains, missed parts and scratching were the most common aspects of deterioration. Some insects were observed by digital microscope. The SEM showed that linen fibers and goat skin were used to manufacture paper sheets and leather binding. Energy dispersive X-ray analysis proved that niobium and tantalum were added during the manufacture of paper sheets. Carbon black ink was the main writing material. The other pigments used were cinnabar in red ink, gold color from brass and blue color from lapis lazuli. FTIR analysis proved that some chemical changes were noticed. Low crystallinity of the historical paper was obtained. There was a reduction in the pH value of the historical bookbinding.
Originality/value
The importance of the analytical techniques used to detect the main components, forms and mechanism of deterioration of the studied manuscript. The elements of niobium and tantalum were added to paper sheets, which protected them from deterioration. The insects such as house flies and Sitophilus granarius were found in the manuscripts.