scholarly journals Innovation potentials for construction materials with specific focus on the challenges in Africa

2020 ◽  
Vol 5 ◽  
pp. 63-74
Author(s):  
Wolfram Schmidt ◽  
Mike Otieno ◽  
Kolawole Olonade ◽  
Nonkululeko Radebe ◽  
Henri Van-Damme ◽  
...  
Keyword(s):  
Environmental Sustainability ◽  
Construction Materials ◽  
Cementitious Materials ◽  
Sustainable Construction ◽  
African Continent ◽  
Concrete Technology ◽  
Rich Diversity ◽  
The Rich ◽  
Basic Infrastructure ◽  
Industrialised Countries

Africa is urgently in need of adequate basic infrastructure and housing, and it is one of the continents where massive construction activities are on the rise. There is a vast variety of potentially viable resources for sustainable construction on the continents, and consequently, the continent can bring innovative, greener technologies based on local sources effectively into practice. However, unlike established concrete constituents from industrialised countries in the global North, most of the innovation potentials from the African continent have not yet been the focus of intensive fundamental and applied research. This clearly limits the implementation of more sustainable local technologies. This paper presents a case for the need to first appreciate the rich diversity and versatility of the African continent which is often not realistically perceived and appreciated. It discusses specific innovation potentials and challenges for cementitious materials and concrete technology based on local materials derived from sources on the African continent. The unique African materials solutions are presented and discussed, from mineral binders over chemical admixtures and fibres to reinforcement and aggregates. Due to the pressing challenges faced by Africa, with regards to population growth and urbanisation, the focus is not only put on the technological (durability, robustness and safety) and environmental sustainability, but also strongly on socio-economic applicability, adaptability and scalability. This includes a review of alternative, traditional and vernacular construction technologies such as materials-saving structures that help reducing cementitious materials. Eventually, a strategic research roadmap is hypothesised that points out the most relevant potentials and research needs for quick implementation of more localised construction materials.

State of the art on geopolymer concrete

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zoi G. Ralli ◽  
Stavroula J. Pantazopoulou
Keyword(s):  
Mechanical Performance ◽  
State Of The Art ◽  
Construction Materials ◽  
Cementitious Materials ◽  
Sustainable Construction ◽  
Geopolymer Concrete ◽  
Critical Material ◽  
Content Type ◽  
Critical Requirement

PurposeImportant differentiating attributes in the procedures used, the characteristic mineral composition of the binders, and the implications these have on the final long term stability and physico-mechanical performance of the concretes produced are identified and discussed, with the intent to improve transparency and clarity in the field of geopolymer concrete technologies.Design/methodology/approachThis state-of-the-art review covers the area of geopolymer concrete, a class of sustainable construction materials that use a variety of alternative powders in lieu of cement for composing concrete, most being a combination of industrial by-products and natural resources rich in specific required minerals. It explores extensively the available essential materials for geopolymer concrete and provides a deeper understanding of its underlying chemical mechanisms.FindingsThis is a state-of-the-art review introducing the essential characteristics of alternative powders used in geopolymer binders and the effectiveness these have on material performance.Practical implicationsWith the increase of need for alternative cementitious materials, identifying and understanding the critical material components and the effect they may have on the performance of the resulting mixes in fresh as well as hardened state become a critical requirement to for short- and long-term quality control (e.g. flash setting, efflorescence, etc.).Originality/valueThe topic explored is significant in the field of sustainable concrete technologies where there are several parallel but distinct material technologies being developed, such as geopolymer concrete and alkali-activated concrete. Behavioral aspects and results are not directly transferable between the two fields of cementitious materials development, and these differences are explored and detailed in the present study.

scholarly journals The Future and Prospects of Periwinkle Composites in Reinforced Concretes: A Review

2021 ◽  
pp. 49-67
Author(s):  
Nkwoada Amarachi ◽  
Onyedika Gerald ◽  
Oguzie Emeka ◽  
Ogwuegbu Martin
Keyword(s):  
Building Materials ◽  
Construction Materials ◽  
Cementitious Materials ◽  
Economic Benefits ◽  
Concrete Technology ◽  
Naturally Occurring ◽  
Cost Of Construction ◽  
Shell Powder ◽  
Periwinkle Shell ◽  
Curing Age

The choice of building materials and the rising cost of construction materials have continued to plaque the building and construction industry without an immediate solution. Industrialists and scholars are investigating several naturally occurring materials for concrete composite reinforcements. The article chronologically reviewed the growth and development of periwinkle shell powder (PSP) and periwinkle ash powder (PSA) as composite materials in concretes. Findings showed that 28 days of curing age are required for lightweight concretes reinforced with PSP or PAP at 10-30% optimum. Produced lightweight concretes were susceptible to acidic medium and induce lower compressive strength which eventually leads to concrete/structure disintegrate and collapse. Research challenges and funding hamper the application of PSP/PAP in the concrete formulation and are unable to drive innovations and economic benefits as a composite. Advances in concrete technology showed that PSP/PSA mollusk shells achieve pillar strength grade and weight/load bearing status for the improvement of PSP/PSA blended concretes. Also, the composite potential showed that the functionalization of PSP/PSA, sustainability, and nano modification of cementitious materials and concretes are promising. Future studies are required to develop periwinkle reinforced concrete silos, sewers, and smart concrete materials with improved mechanical, thermal, and aesthetic properties.

scholarly journals Materials From Hazardous Iron Ore Treatment Waste, Concrete Demolition Debris And Lime Production Waste to Increase Environmental Sustainability of Industrial Regions

2021 ◽  
Author(s):  
Vsevolod Mymrin ◽  
Ana Povaluk ◽  
Luana Cechin ◽  
Monica A. Avanci ◽  
Cleber L. Pedroso ◽  
...  
Keyword(s):  
Environmental Sustainability ◽  
Iron Ore ◽  
Construction Materials ◽  
Solid Particles ◽  
Production Waste ◽  
Sustainable Construction ◽  
Natural Rock ◽  
Concrete Production ◽  
Ore Treatment ◽  
Lime Production

Abstract To prevent environment pollution by hazardous industrial dumps of iron ore treatment sludge, concrete production/demolition debris and lime production waste sustainable cement-less construction materials were developed for substitution of traditional natural raw components excavated in careers, irreversibly destroying natural bonds. Their ​​ axial resistance values on the 3rd day of hydration were till 2.34 MPa, on the 28th day - up to 3.94 MPa, on the 180th day 8.40 MPa and on the 365th day 10.22 MPa. The expanding coefficient on the 3rd day were till 2.13%, 2.51% on the 28th day, and on the 365th day 2.22%. Water absorption on the 28th day was 7.17 - 9.32% and decreases to 6.26 - 8.64% on the 90th day. All these characteristics correspond to the Brazilian norms. The physical - chemical processes of materials’ structures formation included alkaline dissociation of solid particles’ surface, with sol appearing and densification till transition to gel. Long-lasting gel compaction and densification to stone-like condition made its structure similar to natural rock materials - silica, opal, obsidian, perlite, pumice, amber, flask, etc. They can be used for production of road bases, concrete blocks and solid unburned bricks, among other sustainable construction materials.

scholarly journals Urban Advantage? Sustainability Trade-Offs Across and Within the Intra-Urban Space

2021 ◽  
pp. 283-313 ◽  
Author(s):  
Lin Lerpold ◽  
Örjan Sjöberg ◽  
Wing-Shing Tang
Keyword(s):  
Urban Space ◽  
Environmental Sustainability ◽  
Construction Materials ◽  
Social Sustainability ◽  
Urban Morphology ◽  
Sustainable Construction ◽  
Sustainable City ◽  
Rebound Effects ◽  
Trade Offs ◽  
Spatial Sorting

Abstract“Sustainable cities” as a singular concept may very well be a utopian vision impossible to realise in a broader sense. In this chapter, we review the literature on urban sustainability highlighting the complexities and trade-offs between and within the 3 Es—ecology, economy and equality. In particular, we focus here on the intra-urban dimensions of density, mobility, the built environment and housing, lifestyle trends and gentrification along with social sustainability issues of crime, homelessness and community. While gains from increased size and density can be had, there are also many outcomes that depend on urban morphology and the consequences of spatial sorting. Positive outcomes generated by density and efficiency may be offset by, for instance, less sustainable construction materials or increased income inequality. In particular, rebound effects are often overlooked. Hence, it often becomes an empirical issue whether the potential for sustainability gains materialise. Furthermore, as assessed from a more holistic 3 Es’ view, where social sustainability is as important as environmental sustainability, the potential of a “sustainable city” may be a victim of trade-offs that are difficult to resolve.

Conclusion

2018 ◽  
Author(s):  
Stefan Winter
Keyword(s):  
Middle Eastern ◽  
Rich Diversity ◽  
The Social ◽  
Local Contexts ◽  
History Of ◽  
Religious Oppression ◽  
The Rich ◽  
To Come

This concluding chapter summarizes key themes and presents some final thoughts. The book has shown that the multiplicity of lived ʻAlawi experiences cannot be reduced to the sole question of religion or framed within a monolithic narrative of persecution; that the very attempt to outline a single coherent history of “the ʻAlawis” may indeed be misguided. The sources on which this study has drawn are considerably more accessible, and the social and administrative realities they reflect consistently more mundane and disjointed, than the discourse of the ʻAlawis' supposed exceptionalism would lead one to believe. Therefore, the challenge for historians of ʻAlawi society in Syria and elsewhere is not to use the specific events and structures these sources detail to merely add to the already existing metanarratives of religious oppression, Ottoman misrule, and national resistance but rather to come to a newer and more intricate understanding of that community, and its place in wider Middle Eastern society, by investigating the lives of individual ʻAlawi (and other) actors within the rich diversity of local contexts these sources reveal.

PSYCHOLOGICAL FEATURES OF EDUCATION AND TOLERANCE IN STUDENTS

2018 ◽  
Vol 16 (1) ◽  
pp. 112-119
Author(s):  
VLADIMIR GLEB NAYDONOV
Keyword(s):  
Statistical Analysis ◽  
Training Program ◽  
Rich Diversity ◽  
Interethnic Differences ◽  
The World ◽  
The Rich ◽  
Correct Understanding ◽  
Psychological Features ◽  
Different Levels

The article considers the students’ tolerance as a spectrum of personal manifestations of respect, acceptance and correct understanding of the rich diversity of cultures of the world, values of others’ personality. The purpose of the study is to investgate education and the formation of tolerance among the students. We have compiled a training program to improve the level of tolerance for interethnic differences. Based on the statistical analysis of the data obtained, the most important values that are significant for different levels of tolerance were identified.

scholarly journals Laboratory Test to Evaluate the Resistance of Cementitious Materials to Biodeterioration in Sewer Network Conditions

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 686
Author(s):  
Amr Aboulela ◽  
Matthieu Peyre Lavigne ◽  
Amaury Buvignier ◽  
Marlène Fourré ◽  
Maud Schiettekatte ◽  
...  
Keyword(s):  
Calcium Aluminate ◽  
Standardized Test ◽  
Performance Indicator ◽  
Cementitious Materials ◽  
Test Method ◽  
Sustainable Construction ◽  
Public Health Issue ◽  
Sulfur Source ◽  
Test Protocol ◽  
Wide Range

The biodeterioration of cementitious materials in sewer networks has become a major economic, ecological, and public health issue. Establishing a suitable standardized test is essential if sustainable construction materials are to be developed and qualified for sewerage environments. Since purely chemical tests are proven to not be representative of the actual deterioration phenomena in real sewer conditions, a biological test–named the Biogenic Acid Concrete (BAC) test–was developed at the University of Toulouse to reproduce the biological reactions involved in the process of concrete biodeterioration in sewers. The test consists in trickling a solution containing a safe reduced sulfur source onto the surface of cementitious substrates previously covered with a high diversity microbial consortium. In these conditions, a sulfur-oxidizing metabolism naturally develops in the biofilm and leads to the production of biogenic sulfuric acid on the surface of the material. The representativeness of the test in terms of deterioration mechanisms has been validated in previous studies. A wide range of cementitious materials have been exposed to the biodeterioration test during half a decade. On the basis of this large database and the expertise gained, the purpose of this paper is (i) to propose a simple and robust performance criterion for the test (standardized leached calcium as a function of sulfate produced by the biofilm), and (ii) to demonstrate the repeatability, reproducibility, and discriminability of the test method. In only a 3-month period, the test was able to highlight the differences in the performances of common cement-based materials (CEM I, CEM III, and CEM V) and special calcium aluminate cement (CAC) binders with different nature of aggregates (natural silica and synthetic calcium aluminate). The proposed performance indicator (relative standardized leached calcium) allowed the materials to be classified according to their resistance to biogenic acid attack in sewer conditions. The repeatability of the test was confirmed using three different specimens of the same material within the same experiment and the reproducibility of the results was demonstrated by standardizing the results using a reference material from 5 different test campaigns. Furthermore, developing post-testing processing and calculation methods constituted a first step toward a standardized test protocol.

scholarly journals Machine Learning Approaches for Prediction of the Compressive Strength of Alkali Activated Termite Mound Soil

2021 ◽  
Vol 11 (11) ◽  
pp. 4754
Author(s):  
Assia Aboubakar Mahamat ◽  
Moussa Mahamat Boukar ◽  
Nurudeen Mahmud Ibrahim ◽  
Tido Tiwa Stanislas ◽  
Numfor Linda Bih ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Construction Materials ◽  
Curing Temperature ◽  
Sustainable Construction ◽  
Support Vector ◽  
Learning Approaches ◽  
Artificial Neural Network Ann ◽  
Curing Regime ◽  
Alkali Activated

Earth-based materials have shown promise in the development of ecofriendly and sustainable construction materials. However, their unconventional usage in the construction field makes the estimation of their properties difficult and inaccurate. Often, the determination of their properties is conducted based on a conventional materials procedure. Hence, there is inaccuracy in understanding the properties of the unconventional materials. To obtain more accurate properties, a support vector machine (SVM), artificial neural network (ANN) and linear regression (LR) were used to predict the compressive strength of the alkali-activated termite soil. In this study, factors such as activator concentration, Si/Al, initial curing temperature, water absorption, weight and curing regime were used as input parameters due to their significant effect in the compressive strength. The experimental results depict that SVM outperforms ANN and LR in terms of R2 score and root mean square error (RMSE).

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