Physical, Thermal and Microstructural Characterization of Earth Mortars Stabilized with Incorporating Air Additive

Author(s):  
Rayane de Lima Moura Paiva ◽  
Patrícia Brandão Sousa ◽  
Camila de Barros Lima Carreira ◽  
Adriana Paiva Souza Martins ◽  
Romildo Dias Toledo Filho

In recent years, the search for non-conventional materials has intensified, aiming to reduce environmental impacts in the civil construction sector as a strategy for more sustainable development. Among these materials, earth mortars are a promising option, as they have technological, economic, and environmental advantages. Due to the absence of literary data on the use of air-incorporating additives (AEA) in earth mortars, the objective of this article is to verify the influence of the incorporation of AEA (0,10, 20, and 40% of the total volume of the mixture) in the mechanical properties (compression strength at 28 days), physical (total water absorption by immersion), thermal, and microstructural (scanning electron microscopy) of the referred mortars. The study was carried out in a stabilized earth mortar, with a 1:3 mass mix proportion (binder: aggregate). The raw materials used were constituted by binders (cement, hydrated lime, fly ash, metakaolinite), aggregates (sand, a coarse fraction of the soil), additives (AEA, calcium chloride, superplasticizer), and water. The water-binder material ratio (a / bm) was fixed at 0.65, and the consumption of binder and aggregate was 461.71 and 1385.12 kg, respectively, per m3 of the mixture. The tests demonstrated that the incorporation of the additive influenced the behavior under compression (strength and stiffness reduction), thermal performance (conductivity reduction), and physical behavior (absorption and voids index´s increases) compared to the mixture without AEA. From the analysis of the results, it was found that the incorporation of air in the mortars led to an increase in porosity, directly influencing the thermal insulation capacity, measured by thermal conductivity. Microstructure changes were observed through SEM images, corroborating the influence of the AEA. Under compression loads, the stiffness reduction decreases the risk of eventual cracking, however, the reduction in strength should be controlled to meet normative limits.

Author(s):  
C. J. Chan ◽  
K. R. Venkatachari ◽  
W. M. Kriven ◽  
J. F. Young

Dicalcium silicate (Ca2SiO4) is a major component of Portland cement. It has also been investigated as a potential transformation toughener alternative to zirconia. It has five polymorphs: α, α'H, α'L, β and γ. Of interest is the β-to-γ transformation on cooling at about 490°C. This transformation, accompanied by a 12% volume increase and a 4.6° unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation in zirconia. Due to the processing methods used, previous studies into the particle size effect were limited by a wide range of particle size distribution. In an attempt to obtain a more uniform size, a fast quench rate involving a laser-melting/roller-quenching technique was investigated.The laser-melting/roller-quenching experiment used precompacted bars of stoichiometric γ-Ca2SiO4 powder, which were synthesized from AR grade CaCO3 and SiO2xH2O. The raw materials were mixed by conventional ceramic processing techniques, and sintered at 1450°C. The dusted γ-Ca2SiO4 powder was uniaxially pressed into 0.4 cm x 0.4 cm x 4 cm bars under 34 MPa and cold isostatically pressed under 172 MPa. The γ-Ca2SiO4 bars were melted by a 10 KW-CO2 laser.


Author(s):  
M. G. Burke ◽  
M. N. Gungor ◽  
M. A. Burke

Intermetallic matrix composites are candidates for ultrahigh temperature service when light weight and high temperature strength and stiffness are required. Recent efforts to produce intermetallic matrix composites have focused on the titanium aluminide (TiAl) system with various ceramic reinforcements. In order to optimize the composition and processing of these composites it is necessary to evaluate the range of structures that can be produced in these materials and to identify the characteristics of the optimum structures. Normally, TiAl materials are difficult to process and, thus, examination of a suitable range of structures would not be feasible. However, plasma processing offers a novel method for producing composites from difficult to process component materials. By melting one or more of the component materials in a plasma and controlling deposition onto a cooled substrate, a range of structures can be produced and the method is highly suited to examining experimental composite systems. Moreover, because plasma processing involves rapid melting and very rapid cooling can be induced in the deposited composite, it is expected that processing method can avoid some of the problems, such as interfacial degradation, that are associated with the relatively long time, high temperature exposures that are induced by conventional processing methods.


2014 ◽  
Vol 6 (2) ◽  
pp. 1
Author(s):  
Saibatul Hamdi

The purpose of this research is to know the mechanical strength of gypsum board by utilizing waste sawn wood. Raw materials used consist of flour, gypsum,wood particles, boraks and kambang (Goniothalamus sp), wood tarap (Artocarpus elasticus REINW) and lua (Ficus glomerata ROXB). Wood particle 40 mesh and 60 mesh, concentrations boraks of 1 and 2 and the percentage particles of gypsum sawn timber is 300, 400 and 500%. The results showed that the average value Modulus of Rufture (MoR) in lua wood ranges from 12.55 – 14,47 kgcm2, wood kambang 25.10-31,11 kgcm2 and wood tarap 19.20- 24,18 kgcm2. As for Modulus of Elasticity (MoE) on the lua 1129,80- 2092,70 kgcm2, wood kambang 2512,37-3971,32 kgcm2 and tarap 2050,63-2691,09 kgcm2. Gypsum board are mechanical properties do not meet quality standards created SNI 03-6434-2000.Keywords: sawdust, lua, kambang, tarap, gypsum, mechanical


Author(s):  
Chernichkina A.D.

A large number of biologically active substances, organic acids, tannins, and pectin substances were detected during the study of fruits, leaves, and pulp of the fruits of mountain Ash. The content of these substances in leaves and pulp will significantly expand the arsenal of medicinal plant raw materials used. Given the wide distribution of mountain Ash in the territory of the Russian Federation, harvesting leaves from the same plants after harvesting the fruit and using pulp will make it possible to obtain new phytopreparations.


Food Industry ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 71-78
Author(s):  
Ekaterina Minnikhanova ◽  
Nataliya Zavorokhina ◽  
Anna Gilina

Abstract The inclusion of polysaccharide thickeners in the recipes of sweet dishes increases the functional reserves of the body, contributes to the preservation of health and the prevention of diseases. The purpose of the research is to study the sensory characteristics of polysaccharides of various nature when combined with food acids, to develop a recipe for a basic mixture of low-calorie meals for public catering. The authors analyzed citric, lactic and succinic acids in combinations with polysaccharides of various nature. Organoleptic tests were evaluated by a touch panel. The organization of the tasting analysis corresponded to GOST ISO 6658-2016; the consistency was determined according to GOST 31986-2012, GOST ISO 11036-2017, GOST ISO 8588-2011. The optimal organoleptic combinations of the presented food acids and complex additives of sweeteners (CDP) were identified, which included aspartame, sodium saccharinate, Sucralose, sweetness coefficient – 340: the mixture with citric acid had a long pleasant aftertaste without foreign tastes and the best taste characteristics. Using the “A-not A” method, we found that the sample with the addition of CDP is identical to the sucrose solution. In the second part of the study, polysaccharides were added to model samples of acids with complex sweeteners; the best sensory characteristics were obtained by model samples consisting of a mixture of low-esterified Apple pectin with lactic acid and KDP. The technology of obtaining a stable elastic jelly using low-esterified Apple pectin has been developed, since the complex mixture of sweeteners and food acids does not have a dehydrating effect. Developed a dry mix recipe that can serve as a basic development, low-calorie sweet products for catering and has a variance of use of lactic and succinic acids, depending on the flavor characteristics of the raw materials used and its corrective ability.


2020 ◽  
Vol 4 (2) ◽  
Author(s):  
Ivan Yulianto ◽  
Ario Seno Nugroho

An alternative strategy to reduce the trade balance deficit simultaneously to increase the net foreign exchange is the import-substitution for raw materials used to produce an export goods. This paper proposes an import substitution study on footwear products that have a dependency on imported raw materials by 70 percent, with the largest composition being leather raw materials by 67 percent. This paper analyzes the relationship between subsidies on the leather industry to leather import-substitution, multiplier effect to footwear sector, and Indonesia trade balance. Author make use of simulation the on Input-Output 2010 table and Computable General Equilibrium (CGE) Model. The simulation shows 100 billion subsidies on the leather sector, lead for the substitution-import of leather by 7,94 million rupiah, increase the net export foreign exchange by 1.1 billion rupiah of the footwear sector, and for overall, increase Indonesia trade balance deficit by 68 billion rupiah. Keywords: Computable General Equilibrium, footwear, leather, net foreign exchange, subsidy.ABSTRAK: Salah satu terobosan untuk mengurangi defisit neraca perdagangan dan meningkatkan nilai neto devisa ekspor adalah dengan substitusi impor bahan baku yang digunakan untuk memproduksi barang ekspor. Paper ini mengusulkan kajian substitusi impor pada produk alas kaki yang mempunyai ketergantungan bahan baku impornya sebesar 70 persen, dengan komposisi terbesar adalah bahan baku kulit sebesar 67 persen. Tujuan penelitian ini adalah untuk mengetahui dampak stimulus subsidi pada industri kulit terhadap subtitusi impor kulit, dukungan multiplier sektor kulit terhadap sektor alas kaki, serta terhadap devisa ekspor Indonesia. Penelitian ini menggunakan simulasi model Computable General Equilibrium (CGE). Hasil simulasi menunjukkan stimulus subsidi sebesar 100 milyar rupiah pada sektor kulit memberikan substitusi bahan baku kulit sebesar 7,94 juta rupiah, menaikkan devisa ekspor sektor alas kaki sebesar 1.1 miliar rupiah, serta secara keseluruhan menambah defisit neraca berjalan Indonesia sebesar 68 miliar rupiah. Kata kunci: alas kaki, Computable General Equilibrium (CGE), devisa ekspor, kulit, subsidi.


2012 ◽  
Vol 7 (4) ◽  
Author(s):  
Norikazu Sugaya

This new surface treatment is simple and easy as well as low in cost. The processes can even be performed by hand. Pharmaceutical raw materials used for the surface treatment, such as hydrochloric acid and nitric acid used in a mixed acid washing process and vegetable oil used in an organic film forming process, are easily obtained in many countries.


Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2237 ◽  
Author(s):  
P. R. Sarika ◽  
Paul Nancarrow ◽  
Abdulrahman Khansaheb ◽  
Taleb Ibrahim

Phenol–formaldehyde (PF) resin continues to dominate the resin industry more than 100 years after its first synthesis. Its versatile properties such as thermal stability, chemical resistance, fire resistance, and dimensional stability make it a suitable material for a wide range of applications. PF resins have been used in the wood industry as adhesives, in paints and coatings, and in the aerospace, construction, and building industries as composites and foams. Currently, petroleum is the key source of raw materials used in manufacturing PF resin. However, increasing environmental pollution and fossil fuel depletion have driven industries to seek sustainable alternatives to petroleum based raw materials. Over the past decade, researchers have replaced phenol and formaldehyde with sustainable materials such as lignin, tannin, cardanol, hydroxymethylfurfural, and glyoxal to produce bio-based PF resin. Several synthesis modifications are currently under investigation towards improving the properties of bio-based phenolic resin. This review discusses recent developments in the synthesis of PF resins, particularly those created from sustainable raw material substitutes, and modifications applied to the synthetic route in order to improve the mechanical properties.


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Lino Bianco

AbstractRuins are a statement on the building materials used and the construction method employed. Casa Ippolito, now in ruins, is typical of 17th-century Maltese aristocratic country residences. It represents an illustration of secondary or anthropogenic geodiversity. This paper scrutinises these ruins as a primary source in reconstructing the building’s architecture. The methodology involved on-site geographical surveying, including visual inspection and non-invasive tests, a geological survey of the local lithostratigraphy, and examination of notarial deeds and secondary sources to support findings about the building’s history as read from its ruins. An unmanned aerial vehicle was used to digitally record the parlous state of the architectural structure and karsten tubes were used to quantify the surface porosity of the limestone. The results are expressed from four perspectives. The anatomy of Casa Ippolito, as revealed in its ruins, provides a cross-section of its building history and shows two distinct phases in its construction. The tissue of Casa Ippolito—the building elements and materials—speaks of the knowledge of raw materials and their properties among the builders who worked on both phases. The architectural history of Casa Ippolito reveals how it supported its inhabitants’ wellbeing in terms of shelter, water and food. Finally, the ruins in their present state bring to the fore the site’s potential for cultural tourism. This case study aims to show that such ruins are not just geocultural remains of historical built fabric. They are open wounds in the built structure; they underpin the anatomy of the building and support insights into its former dynamics. Ruins offer an essay in material culture and building physics. Architectural ruins of masonry structures are anthropogenic discourse rendered in stone which facilitate not only the reconstruction of spaces but also places for human users; they are a statement on the wellbeing of humanity throughout history.


2021 ◽  
Vol 11 (10) ◽  
pp. 4392
Author(s):  
Apolka Ujj ◽  
Kinga Percsi ◽  
Andras Beres ◽  
Laszlo Aleksza ◽  
Fernanda Ramos Diaz ◽  
...  

The use and quality analysis of household compost have become very important issues in recent years due to the increasing interest in local food production and safe, self-produced food. The phenomenon was further exacerbated by the COVID-19 pandemic quarantine period, which gave new impetus to the growth of small home gardens. However, the knowledge associated with making high-quality compost is often lacking in home gardeners. Therefore, the objective of this research was to find answers to the following questions: can the quality of backyard compost be considered safe in terms of toxicity and nutrient content? Can weed seed dispersion affect the usability of backyard compost? In general, can the circulation of organic matter be increased with the spread of home composting? In this study, 16 different house composts were analysed for stability, weed seed contamination, toxic elements, and nutrient content using analysis of variance. The results of the research showed that the quality properties of the composts (including their weed seed dispersion effect) were greatly influenced by the different techniques and raw materials used. The toxicity levels, as well as the content of macro and microelements, were within the parameters of safe-quality compost. The specific macronutrient (Ca, Mg) and micronutrient (Fe, Mn) contents of the tested composts have a similar and, in some cases, more favorable nutrient supply capacity in crop production than the frequently-used cow manure-based composts. With a plan of basic education on composting, there is potential to encourage farmyard composting.


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