The alkali-activated slag (AAS) cement is an interesting building material, confronting to the new economical and ecological challenges. In order to enhance its physical…
Abstract
The alkali-activated slag (AAS) cement is an interesting building material, confronting to the new economical and ecological challenges. In order to enhance its physical properties in comparison with ordinary Portland cement (OPC), we used natural pozzolana as a mineral addition. The parameters studied are: the fineness of the addition (5350 and 5650 cm2/g), and its percentage (0 to 30%). The activator used is NaOH (5M) and the curing temperature was fixed at 20°C. The results show the possibility to obtain compound alkali-activated slag cement with better stability and a compressive strength higher than 35 MPa.
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Mohammed Seghir Ammari, Mohammed Bachir Tobchi, Yahia Amrani, Anouer Mim, Madani Bederina and Ahmida Ferhat
This study is part of the valorization of local materials and the reuse of industrial waste in construction. This study aims to improve the physical-mechanical properties of sand…
Abstract
Purpose
This study is part of the valorization of local materials and the reuse of industrial waste in construction. This study aims to improve the physical-mechanical properties of sand concrete. This work is a continuation of previous studies conducted on sand concrete, the purpose of which is to introduce industrial waste into this material. For this purpose, a glass waste in powder form is added.
Design/methodology/approach
This study is focused on the effect of adding glass powder (GP) whose mass percentage varies from 0 to 40% with an interval of 10% to target the right composition that ensures the best compromise between the characteristics studied.
Findings
The results found show that the workability and density of the studied concretes decreased with increasing GP dosage. Indeed, the optimal addition which constitutes the best compromise between the studied properties is 10% of GP. Improvements of up to about 9% in the case of flexural strength and about 18% in the case of compressive strength. The thermal conductivity has been reduced by 12.74%, the thermal diffusivity which characterizes the notion of thermal inertia has been reduced by about 4% and the specific heat mass has been reduced by 7.80%. Also, the shrinkage has been reduced by about 20%. The microstructure of the studied composite shows a good homogeneity between the aggregates. Finally, the addition of GP to sand concrete gives very encouraging results.
Originality/value
The interest of this study is in two parts. The first one is the exploitation of local materials: dune sand, river sand and limestone filler to meet the growing demand for construction materials. And the second one is the reuse of glass waste, in the form of powder (GP), to solve the environmental problem. All this participates in the improvement of the physical-mechanical properties of sand concrete and the extent of its response to the development of an economical structural concrete.
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Ahmed Attia, Salim Guettala and Rebih Zaitri
The purpose of this paper is to implement the mathematical models to predict concretes physico-mechanical characteristics made with binary and ternary sands using a mixture design…
Abstract
Purpose
The purpose of this paper is to implement the mathematical models to predict concretes physico-mechanical characteristics made with binary and ternary sands using a mixture design method. It is a new technique that optimizes mixtures without being obliged to do a lot of experiments. The goal is to find the law governing the responses depending on mixture composition and capable of taking into account the effect of each parameter separately and in interaction between several parameters on the characteristics studied.
Design/methodology/approach
Mixture design method was used for optimizing concretes characteristics and studying the effects of river sand (RS), dune sand (DS) and crushed sand (CS) in combinations of binary system and ternary on workability, the compressive and flexural strengths of concretes at 7 and 28 days. A total of 21 mixtures of concrete were prepared for this investigation. The modeling was carried out by using JMP7 statistical software.
Findings
Mixture design method made it possible to obtain, with good precision, the statistical models and the prediction curves of studied responses. The models have relatively good correlation coefficients (R2 = 0.70) for all studied responses. The use of binary and ternary mixtures sands improves the workability and their mechanical strengths. The obtained results proved that concrete, based on binary mixture C15, presents the maximum compressive strength (MCS) on 28 day with an improvement of around 20%, compared to reference concrete (C21). For ternary mixtures, MCS on 28 day was obtained for the mixture C10 with an improvement of around 15% compared to C21. Increase in compressive strength during the progress of hydration reactions was accompanied by an increase in the flexural strength, but in different proportions.
Originality/value
The partial incorporation of DS (= 40%) in the concrete formulation can provide a solution for some work in the southern regions of country. In addition, the CS is an interesting alternative source for replacing 60% of RS. The concrete formulation based on local materials is really capable of solving the economic and technical problems encountered in the building field, as well as environmental problems. Local resources therefore constitute an economic, technological and environmental alternative.
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Subhash Yaragal, Chethan Kumar B. and Manoj Uddavolu Abhinav
To reduce environmental impact caused by excessive use of ordinary Portland cement (OPC) and to mitigate scarcity of base materials such as natural coarse aggregate (NCA)…
Abstract
Purpose
To reduce environmental impact caused by excessive use of ordinary Portland cement (OPC) and to mitigate scarcity of base materials such as natural coarse aggregate (NCA), industrial by-products can be carefully used as alternatives to OPC and NCA, in production of concrete. This paper aims to describe the performance of using ground granulated blast furnace slag (GGBS), fly ash (FA) as a complete replacement to OPC and ferrochrome slag (FCS) as replacement to NCA in production of novel FCS based alkali activated slag/fly ash concretes (AASFC) and evaluate their performance at elevated temperatures.
Design/methodology/approach
Two control factors with three levels each i.e. FA (0, 25 and 50 per cent by weight) and FCS (0, 50 and 100 per cent by volume) as a GGBS and NCA replacement, respectively, were adopted in AASFC mixtures. Further, AASFC mixture specimens were subjected to different levels of elevated temperature, i.e. 200°C, 400°C, 600°C and 800°C. Compressive strength and residual compressive strength were considered as responses. Three different optimization techniques i.e. gray relational analysis, technique for order preference by similarity to ideal solution and Desirability function approach were used to optimize AASFC mixtures subjected to elevated temperatures.
Findings
As FA replacement increases in FCS based AASFC mixtures, workability increases and compressive strength decreases. The introduction of FCS as replacement to NCA in AASFC mixture did not show any significant change in compressive strength under ambient condition. AASFC produced with 75 per cent GGBS, 25 per cent FA and 100 per cent FCS was found to have excellent elevated temperature enduring properties among all other AASFC mixtures studied.
Originality/value
Although several studies are available on using GGBS, FA and FCS in production of OPC-based concretes, present study reports the performance of novel FCS based AASFC mixtures subjected to elevated temperatures. Further, GGBS, FA and FCS used in the present investigation significantly reduces CO2 emission and environmental degradation associated with OPC production and NCA extraction, respectively.
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Mounira Chadli, Mellas Mekki and Bouzidi Mezghiche
Reactive powder concretes (RPCs) are new concretes characterized by a particle diameter not exceeding 600 µm and very high compressive and tensile strengths. This paper aims to…
Abstract
Purpose
Reactive powder concretes (RPCs) are new concretes characterized by a particle diameter not exceeding 600 µm and very high compressive and tensile strengths. This paper aims to the development and study of the physico-mechanical, elastic properties and durability of an ultra-high performance concrete from materials existing on the Algerian market.
Design/methodology/approach
Three mineral additions such as granulated slag, quartz powder and silica fume are incorporated into the cement with 15, 23 and 25 per cent, respectively, in addition to use two different values of steel fiber volume fraction (2 and 2.5 per cent). The results show that the incorporation of 2.5 per cent metal fibers in the formulation of the RPC gives a high compressive strengths of 143.5 MPa at 60 days. The relationship between the relative value and the longitudinal elasto-instantaneous deformations of the RPC to a linear characteristic throughout the relative stress ranges. Also, the modulus of elasticity developed for a fiber-reinforced reactive concrete is greater than that of the unbound fiber.
Findings
Results from the current study concluded that the presence of the mineral additions improves the durability of the concretes compared with that not adjuvanted by mineral additions.
Originality/value
It can be possible to manufacture fiber-reinforced reactive powder concretes (RPCFs) with compressive strength exceeding 140 MPa, with an adequate plasticity, despite the simplicity of means and materials and the incorporation of different percentage of metal fiber on the mechanical strength of concretes and its influence on behavior with respect to aggressive environment were achieved.
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Saoussen Lakhdar and Fatma Smaoui
This paper aims to explore the socio-cultural meanings of functional foods for Tunisian consumers and to understand how these meanings shape their preferences and practices in the…
Abstract
Purpose
This paper aims to explore the socio-cultural meanings of functional foods for Tunisian consumers and to understand how these meanings shape their preferences and practices in the particular context of a Middle-East and North African (MENA) region.
Design/methodology/approach
A constructivist perspective based on multi-qualitative methods was designed allowing data collection in a natural setting through focus groups interviews, individual in-depth interviews and projective techniques among Tunisian consumers.
Findings
Findings show the complexity and importance of conscious and unconscious non-health-related socio-cultural factors in the construction and acceptance of functional foods by the Tunisian consumer. Common sense knowledge, social environment and tradition shape the constructions and practices of functional foods. These factors may act as a shortcut to compensate for unhealthy behaviour and as a social marker to reflect trendiness and identity.
Research limitations/implications
The findings are specific to the Tunisian setting and may be not transferable to other settings.
Practical implications
The role of information is central in functional food acceptance. Communication on health effects should consider not only the formal nutritional health benefit but also lay knowledge.
Social implications
The findings of this research contribute in the government’s understanding of Tunisian’s constructions of health and well-being by suggesting that besides health motives, non-health-related factors such as lay knowledge, social influences and conspicuous consumption play an important role in functional foods choice.
Originality/value
This paper contributes to extend functional foods literature by exploring the complex interconnected conscious and unconscious socio-cultural constructions behind functional food choice. It contributes also to the understanding of the food consumer behaviour in the specific cultural context of the Arab-Muslim MENA region, an under investigated setting.
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Juciane de Abreu Ribeiro Pereira, Maria de Fátima Piccolo Barcelos, Eric Batista Ferreira, Rafaela Corrêa Pereira and Michel Cardoso de Angelis-Pereira
As studies investigating the effects of fructan sources, such as yacon, on glucose and lipid metabolism showed different results, additional research is required to establish a…
Abstract
Purpose
As studies investigating the effects of fructan sources, such as yacon, on glucose and lipid metabolism showed different results, additional research is required to establish a clear relationship between them. Thus, this paper aims to evaluate possible effects of the consumption of the yacon pulp flour (YPF) on biological and metabolic parameters such as food consumption, weight gain, serum glucose levels and fecal lipid excretion of rats, as well as determine the role of glycemic index (GI) of the diets added of this ingredient on those parameters.
Design/methodology/approach
For this purpose, 24 male albino Wistar rats were divided into four groups, which received the following treatments for 17 days: Group 1 (G1) (Control) – American Institute of Nutrition (AIN)-M; Group 2 (G2) – AIN-M added 5 per cent YPF; Group 3 (G3) – AIN-M added 10 per cent YPF and Group 4 (G4) – AIN-M added 15 per cent YPF. Analysis of fasting and postprandial glycemia was conducted for elaboration of the glycemic curve and calculation of the GI of the diets. Lipids loss was measured by quantification of crude fat in feces after consumption of the diet.
Findings
YPF, regarding the concentration in the diets, did not elevate the fasting glucose among the groups. The postprandial glucose of the animals declined in different postprandial glucose peaks of the groups ingesting YPF in relation to the control one, especially in group treated with 15 per cent YPF, between 30 and 60 min (p <0,05), confirming the influence of the dietary fiber on the absorption of the glucose. The ingestion of YPF increased dragging of lipids to the animal feces, proportional to the amounts of YPF added to the diets. According to the regression analysis, followed by regression testing to 5 per cent, there was a significant difference between the experimental groups, being that the elevation of the percentage of YPF added to the diet caused a proportional increase in the lipid levels in the animal feces.
Originality/value
YPF could be an alimentary source of interest, mainly when the focus is on disease risk prevention such as diabetes, obesity and dyslipidemias.