Efflorescence Formation Mechanism and Control for Geopolymer Paste Specimens Made from Natural Pozzolan and Calcium Hydroxide Binders
Asson Sifueli Malisa,
Duwa Hamisi Chengula
Issue:
Volume 9, Issue 2, June 2023
Pages:
14-20
Received:
19 May 2023
Accepted:
10 June 2023
Published:
21 June 2023
Abstract: The use of alkali activated geopolymer binders in the recent years has received much attention because of their outstanding mechanical properties, reduction of CO2 emissions and low energy for production. While number of researches are being done to develop geopolymer binders, their application is still limited. Efflorescence phenomena is one of the limitations of the extensive use of geopolymers. The efflorescence not only affect the materials aesthetics, but it also affects its mechanical performance. The present study outlines the general features of efflorescence, including its formation mechanism, chemical and mineralogical composition. Natural pozzolan from Songwe – Mbeya, Tanzania, calcium hydroxide, sodium silicate and sodium hydroxide were used as raw materials for geopolymerization process. It has been observed that efflorescence is formed on alkali activated paste specimens which were partially soaked in water. The formation of efflorescence products is formed due to unbalanced concentration of alkaline solution within the specimen. The produced efflorescence powders were tested for chemical and mineralogical compositions. The chemical composition test results indicated the significant percent increase of Na2O for efflorescence powder. This may be due to migration of Na+ from the interior of specimen to the surface during efflorescence formation. The efflorescence powder which was tested for mineralogical composition, indicated the present of some amount of calcite, mica, sodium carbonate hydrate and quartz. One of the control process of efflorescence formation on alkali activated geopolymer specimens is by maintaining equilibrium of alkali concentration within the specimens during curing process.
Abstract: The use of alkali activated geopolymer binders in the recent years has received much attention because of their outstanding mechanical properties, reduction of CO2 emissions and low energy for production. While number of researches are being done to develop geopolymer binders, their application is still limited. Efflorescence phenomena is one of th...
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Development and Characterization of Starch Based Bioplatics Using Banana Peels
Fatima Haliru Wali,
Hannatu Sani Abubakar,
Abubakar Umar Birnin-Yauri,
Sayudi Yahaya Haruna
Issue:
Volume 9, Issue 2, June 2023
Pages:
21-25
Received:
18 April 2023
Accepted:
8 May 2023
Published:
27 July 2023
Abstract: A number of significant issues had expedite owing to the increased use of conventional plastic, including the shortage of raw materials for the production of plastic and the buildup of non-biodegradable plastic debris on the planet. Use of ecologically friendly, biodegradable plastic made from renewable resources is one of the problem's promising solutions. The objective of this research is to describe the characteristics of the bio-plastic made from banana peels. In order to create a bioplastic using banana peel powder, a sulphuric acid catalyzed acetylation process was used in the study. The bioplastic produced from this process was then characterized by Fourier Transform Infrared (FT-IR). The FTIR spectra of the product displayed the presence of OH, C-H, C=O and C-O absorption peaks. The results of Chemical resistance test demonstrated that, the produced bioplastic was much closer to or had the same chemical resistance test as traditional plastic, allowing the prepared bioplastic to replace the latter. The new bioplastic also showed some biodegradability and was only slightly affected by acid, salt, and alkali. As a result, it was revealed that, new bioplastics with appreciable material properties could be made from agricultural waste. Hence it may be concluded that bioplastics degrades easily and faster than petroleum based plastics and can be a solution to the long lasted environmental problems caused by petroleum based plastics.
Abstract: A number of significant issues had expedite owing to the increased use of conventional plastic, including the shortage of raw materials for the production of plastic and the buildup of non-biodegradable plastic debris on the planet. Use of ecologically friendly, biodegradable plastic made from renewable resources is one of the problem's promising s...
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