Fig 5
Main effect plot (A), interaction(B), response surface (C), standardized effect and normal probability(D), residual(E), plots and contour(F) for initial setting time.
Source publication
This work deals with the possible use of a renewable resource; the ash of walnut shell as partial replacement for cement to produce an economical and ecologically friendly cementinous binding material for cement, mortar and concrete. The agricultural waste; the walnut shell was processed and converted to ash in order to increase its pozzzolanic pro...
Contexts in source publication
Context 1
... effect plot, interaction plot, main effect plot, normal probability plot, the estimated response surface, contour plot and residue plot for initial and final setting times are shown in Figs. 5 and 6 respectively. It is well noticed from the standardized effect plot (Fig. 5a) that initial setting time increases with increasing W/C ratio, while as Walnut ash content increases setting time decreases up to 22% wt. after which it increases with increasing walnut ash ...
Context 2
... combined interactive effect of the two parameters is indicated in the interaction effect plots (Fig. 5b). In general, no interaction between the parameters resulted in obtaining two parallel lines, but when there is interaction between the parameters, the interaction plot shows non-parallel lines. The plots that can assist to visualize the response surface and show how initial setting time fasten the two factors (W/C and walnut shell ash ...
Context 3
... is interaction between the parameters, the interaction plot shows non-parallel lines. The plots that can assist to visualize the response surface and show how initial setting time fasten the two factors (W/C and walnut shell ash content) in term of response surface are illustrated in three-dimensional (3D) response surface plots presented in (Fig. 5C). The normal probability plot indicated that the points are almost close to the straight line (Fig. 5D) and hence the model is considered to be ...
Context 4
... can assist to visualize the response surface and show how initial setting time fasten the two factors (W/C and walnut shell ash content) in term of response surface are illustrated in three-dimensional (3D) response surface plots presented in (Fig. 5C). The normal probability plot indicated that the points are almost close to the straight line (Fig. 5D) and hence the model is considered to be ...
Context 5
... two-dimensional (2D) contour plot (Fig. 5D) showed the response values represented by contours (z-scale), while the independent variables are plotted on x-and y-scales. Generally, different interactions between the variables generate different shapes of the contour plots. If the interactions between the variables are significant, an elliptical contour plot is obtained, otherwise ...
Context 6
... the independent variables are plotted on x-and y-scales. Generally, different interactions between the variables generate different shapes of the contour plots. If the interactions between the variables are significant, an elliptical contour plot is obtained, otherwise a circular contour plot is obtained. The plots of the residuals as shown in (Fig. 5E) verify the validity of the regression. The plot shows that the Residuals vs. Predicted are scattered randomly, such as the errors are normally distributed (the points fall randomly on both sides of (0) and are independent of each other). From the results, it can therefore be concluded that the model is suitable for use and can be used ...
Context 7
... effect plot, interaction plot, main effect plot, normal probability plot, the estimated response surface, contour plot and residue plot for initial and final setting times are shown in Figs. 5 and 6 respectively. It is well noticed from the standardized effect plot (Fig. 5a) that initial setting time increases with increasing W/C ratio, while as Walnut ash content increases setting time decreases up to 22% wt. after which it increases with increasing walnut ash ...
Context 8
... combined interactive effect of the two parameters is indicated in the interaction effect plots (Fig. 5b). In general, no interaction between the parameters resulted in obtaining two parallel lines, but when there is interaction between the parameters, the interaction plot shows non-parallel lines. The plots that can assist to visualize the response surface and show how initial setting time fasten the two factors (W/C and walnut shell ash ...
Context 9
... is interaction between the parameters, the interaction plot shows non-parallel lines. The plots that can assist to visualize the response surface and show how initial setting time fasten the two factors (W/C and walnut shell ash content) in term of response surface are illustrated in three-dimensional (3D) response surface plots presented in (Fig. 5C). The normal probability plot indicated that the points are almost close to the straight line (Fig. 5D) and hence the model is considered to be ...
Context 10
... can assist to visualize the response surface and show how initial setting time fasten the two factors (W/C and walnut shell ash content) in term of response surface are illustrated in three-dimensional (3D) response surface plots presented in (Fig. 5C). The normal probability plot indicated that the points are almost close to the straight line (Fig. 5D) and hence the model is considered to be ...
Context 11
... two-dimensional (2D) contour plot (Fig. 5D) showed the response values represented by contours (z-scale), while the independent variables are plotted on x-and y-scales. Generally, different interactions between the variables generate different shapes of the contour plots. If the interactions between the variables are significant, an elliptical contour plot is obtained, otherwise ...
Context 12
... the independent variables are plotted on x-and y-scales. Generally, different interactions between the variables generate different shapes of the contour plots. If the interactions between the variables are significant, an elliptical contour plot is obtained, otherwise a circular contour plot is obtained. The plots of the residuals as shown in (Fig. 5E) verify the validity of the regression. The plot shows that the Residuals vs. Predicted are scattered randomly, such as the errors are normally distributed (the points fall randomly on both sides of (0) and are independent of each other). From the results, it can therefore be concluded that the model is suitable for use and can be used ...
Similar publications
Citations
... We used coarse sums with 20 mm size. The coarse aggregate should be of , Servi et al. 2022, Murts et al. 2021, Kamal et al. 2021) good quality in order to achieve good strength. The coarse aggregates are chosen so that their qualities meet the requirements of IS 383 (1970) Fig. 5. ...
... Hama and Abdulghafor [46] investigated the effects of using a walnut shell as a lightweight aggregate to partially substitute coarse aggregate on various properties and loaddeflection behavior of concrete. The findings revealed that the concrete with 50% WA had a notable drop in strength of 62.57% when compared to the reference slab, and that the crack breadth at failure for the concrete with walnut coarse aggregate was bigger for the reference slab [48]. ...
... According to Kamal et al. [48], walnut shell ash can be used as a green binder to partially replace cement. Cement paste setting times can be maintained by replacing some of the cement with walnut shell ash up to 22% by weight of cement. ...
... Additionally, the findings indicated that using agricultural waste as partial replacements in cement (such as walnut shell ash) is one way to reduce the risks brought on by incorrect waste management. It also significantly lowers the cost of construction [48]. ...
Agricultural waste is one of the wastes with a significant value in producing environmentally friendly materials that can be used in the construction sector. This review paper focuses on the potential uses of walnut shell in some building materials. Walnut shell is a type of agricultural waste that can be converted from waste into usable materials by incorporating it into the manufacture of some building materials to achieve sustainability in the construction industry. Recently, walnut waste has drawn the attention of researchers to generate building-friendly materials to boost sustainability in the construction field. In this sense, the walnut shell’s low specific gravity makes it a viable material, as a cheap agricultural waste product, for the development of building materials. According to a survey of the literature, walnut shells can be utilized in the production of structural elements and thermal insulating concrete, up to 30% and 50% as particles respectively.
... En consecuencia, el material alternativo debe contar por lo menos con este componente. Kamal et al. (2021) indican que a razón de que el concreto es uno de los materiales que se emplea en mayor cuantía hasta alcanzar mil millones de toneladas anuales, se requiere excesivos materiales como los agregados que trae consigo la disminución de los recursos naturales y la fabricación de cemento cuyo impacto ambiental es negativo como la destrucción de ecosistemas y la contaminación del agua, siendo necesario la producción de concretos ecológicos. ...
... In another investigation, pistachio shell ash was utilized as a supplementary cementitious material, where the compressive strength of cement mortar was improved at 10% pistachio shell ash content due to its pozzolanic activity, especially at later ages [38]. Kamal et al. [39] investigated the partial replacement of cement mortar with walnut shell ash as a green pozzolanic admixture, recommending an ash content of up to 22% by weight of cement to retain the cement paste setting times. However, studies on production of agro-waste composites considering replacement of cement by nutshells powder (by weight) still lacking. ...
Different countries have been encountering significant obstacles in the disposal of agro-wastes in landfills, with a recent increase in landfill sites receiving inadequate or no treatment. Moreover, in addition to high disposal costs, several factors related to landfills pose a significant threat to human health and ecosystems-examples include leachates, toxins, and greenhouse gases, which constitute environmental problems. Nutshells are an example of agro-waste materials that can be utilized in different industrial and engineering applications to help save the environment. This study aims to evaluate and investigate the utilization of nutshells (from pistachios, walnuts, and hazelnuts) as a replacement material to produce an agro-waste cement composite. Different nutshell contents (0.5, 1, 1.5, 2, and 2.5% by weight of cement) were used in the preparation of the cement composite mixtures. The nutshells were characterized by X-ray diffraction and energy-dispersive X-ray spectroscopy, and scanning electron microscopy (SEM) was also implemented to observe the prepared cement mortar composites. The compressive strength, hardness, thermal conductivity, and water absorption of cementitious composites were investigated, highlighting that the addition of nutshells significantly enhances the compressive strength. Agro-waste cement composite specimens with a nutshell content of 2.5% exhibited the highest compressive strength. Other properties of the cement composites, such as the thermal insulation properties, were also enhanced by the inclusion of nutshells. For instance, thermal conductivity of all mortar composite samples reduced by 57, 48, and 45% for the addition of 2.5% walnut, pistachio, and hazelnut shells, respectively. This eco-friendly material represents a potential way to address the generation of waste products from agricultural activities and nature; suggested uses of such composites include their application in lightweight panels, thermal insulators, and sustainable building blocks, among several other materials.
This work deals with investigation and optimization of compressive strength of hardened cement-walnut shell ash composite. The impact of the ash content and water/cement ratio on compressive strength were optimized and molded using a statistical software. The results obtained revealed that the bio ash can be used as green binder to replace cement partially. The optimum strength for the cement-ash composites is obtained at the level of 22 wt. % of walnut shell ash as replaced by cement using W/C=0.42. However, higher compressive strength could be achieved using W/C= 0.37. Also, the average densities and water absorption % of the experimental results were analyzed and correlated with the ash content and water/cement ratio. The results showed that incorporation of the bio ash resulted in improvement of the compressive strength, decreasing the density and slightly increase the water absorption. Portland cement binder is prepared and tested for comparison purposes.
As concrete is one of the most used construction materials, lowering its environmental impacts is crucial for a more sustainable built environment. The incorporation of nanomaterials in concrete is a fast-growing field of research because a small amount of nano-compounds can significantly improve some of its properties. Few works have assessed the trade-offs between concrete properties improvement and environmental impacts. This paper reviews the main nanomaterial applications in concrete over the last decade with a focus on their environmental implications. Attention is given to nanotechnology applications boosting innovative properties (i.e., self-compacting, self-cleaning, self-healing, and self-sensing) and green concrete blends incorporating residues, identifying the underlined potential environmental impacts of these applications. Finally, some research gaps and future research directions are identified.
The literature analysis showed that some nanomaterials can improve the mechanical properties of concrete, increase durability, and effectively promote the reduction of cement content, which results in a decrease of CO2 emissions. To allow the comparability of studies and relate carbon emissions with mechanical properties, a carbon intensity index is suggested. Despite different environmental impacts may be reduced in nano-enabled blends, cradle-to-gate life cycle assessment studies showed an increase in other impact categories. Nanomaterial production is often highly energy-intensive, not fully optimized, and still performed at the lab scale. Despite nanomaterial incorporation in concrete is increasing, studies regarding its environmental impacts or its potential ecotoxicity and toxicity (e.g., from a sustainable and safe-by-design perspective) are still scarce and require further investigation.
