Mechanical Properties of Rammed Earth Stabilized with Local Waste and Recycled Materials

2022 ◽  
Author(s):  
Alessia Emanuela Losini ◽  
Liudmila Lavrik ◽  
Marco Caruso ◽  
Monika Woloszyn ◽  
Anne Cecile Grillet ◽  
...  
Keyword(s):  
Clayey Soil ◽  
Firing Process ◽  
Rammed Earth ◽  
Layer By Layer ◽  
Natural Polymers ◽  
Common Procedure ◽  
Recycled Materials ◽  
Hygroscopic Properties ◽  
Weather Resistance ◽  
Agriculture And Food

Traditional techniques of construction using natural and locally available materials are nowadays raising the interest of architects and engineers. Clayey soil is widely present in all continents and regions, and where available it is obtained directly from the excavation of foundations, avoiding transportation costs and emissions due to the production of the binder. Moreover, raw earth is recyclable and reusable after the demolition, thanks to the absence of the firing process. The rammed earth technique is based on earth compressed into vertical formworks layer by layer to create a wall. This material owes its strength to the compaction effort and due to its manufacture procedure exhibits layers resembling the geological strata and possessing high architectural value. The hygroscopic properties of rammed earth allow natural control of the indoor humidity, keeping it in the optimal range for human health. Stabilization with lime or cement is the most common procedure to enhance the mechanical and weather resistance at once. This practice compromises the recyclability of the earth and reduces the hygroscopic properties of the material. The use of different natural stabilizers, fibers, and natural polymers by-products of the agriculture and food industry, can offer an alternative that fits the circular economy requirements. The present study analyses the mechanical strength of an Italian earth stabilized with different local waste and recycled materials that do not impair the final recyclability of the rammed earth.

scholarly journals Possibilities of Use Recycled Materials in Construction Details

2019 ◽  
Vol 279 ◽  
pp. 02011
Author(s):  
Radim Smolka ◽  
Jindřich Sobotka
Keyword(s):  
Thermal Properties ◽  
Economic Costs ◽  
Recycled Materials ◽  
Roof Structure ◽  
Wide Range ◽  
Weather Resistance ◽  
User Friendly ◽  
Flat Roofs ◽  
Secondary Materials

This paper aims to explain the use of secondary materials in design details. Primarily, attention is paid to flat roofs, for which there is currently a wide range of technologies needed for user-friendly operation of a building. Recycled materials are still often looked down on and, therefore, it is important to show that even these elements may work very well in constructions. They must meet strict criteria for static and thermal properties. Furthermore, they must comply with fire and weather resistance requirements. They also have acoustic, secondary and aesthetic function. The roof structure is one of the basic segments that characterize the final properties of the building. Any malfunctions will lead to increased economic costs and degradation of users’ environment.

Research and Application of Green Rammed Earth Wall Construction Technology

2012 ◽  
Vol 512-515 ◽  
pp. 2780-2787
Author(s):  
Tie Gang Zhou ◽  
Dao Qiang Peng ◽  
Jing Hua Cheng
Keyword(s):  
Pilot Project ◽  
Safety Performance ◽  
Rammed Earth ◽  
Layer By Layer ◽  
Construction Technology ◽  
Undisturbed Soil ◽  
Earth Construction ◽  
Rammed Earth Wall ◽  
Simple Processing ◽  
Wall Construction

The traditional rammed earth building refers theses structures which uses tools such as pestle or hammer etc to fill undisturbed soil materials after a simple processing by the method of compacting layer by layer. construction technology of the modern rammed earth mainly makes improvements in terms of rammed earth materials、ramming tools and construction technology which can effectively improve the durability and safety performance of rammed earth building. This article is focusing on how to select scientifically which one is the best rammed earth material and introducing improvement situation about construction technology of rammed earth wall, which combined with researching and practicing of pilot project, under the guidance of the International centre for research and application of earth construction.

scholarly journals Biomedical films of graphene nanoribbons and nanoflakes with natural polymers

RSC Advances ◽  
2017 ◽  
Vol 7 (44) ◽  
pp. 27578-27594 ◽  
Author(s):  
Magda Silva ◽  
Sofia G. Caridade ◽  
Ana C. Vale ◽  
Eunice Cunha ◽  
Maria P. Sousa ◽  
...  
Keyword(s):  
Graphene Nanoribbons ◽  
Layer By Layer ◽  
Natural Polymers ◽  
Free Standing

Novel nanostructured free-standing films based on chitosan, alginate and functionalized flake and ribbon-shaped graphene were developed using the layer-by-layer process.

scholarly journals Natural Polymers for 3D Bioprinting of Organs

2020 ◽  
pp. 30-40
Author(s):  
Galina Sroslova ◽  
Yuliya Zimina ◽  
Elena Nesmeyanova ◽  
Margarita Postnova
Keyword(s):  
Raw Materials ◽  
Sol Gel ◽  
Three Dimensional ◽  
Biologically Active ◽  
Artificial Organs ◽  
Gel Point ◽  
Layer By Layer ◽  
3D Bioprinting ◽  
Natural Polymers ◽  
Biological Origin

Three-dimensional (3D) bioprintingis a well-known promising technology for the production of artificial biological organs providing unprecedented versatility for manipulating cells and other biomaterials with precise control of their location in space. Over the past decade, a number of 3D bioprinting technologies have been developed. Unlike traditional manufacturing technologies, 3D bioprinting allows to produce individual or personalized fabric designs. This helps to deposit cells of the desired type with selected biomaterials and desired biologically active substances. Natural polymers play a leading role in maintaining cellular and biomolecular processes before, during, as well as after three-dimensional bioprinting. Polymers of biological origin can be extracted from natural raw materials by means of physical or chemical methods. These polymers are widely used as effective hydrogels for loading cells to form tissues, build a vascular, nervous, lymphatic network, and also to implement multiple biological, biochemical, physiological, biomedical and other functions. Any natural polymers that have a sol-gel phase transition (i.e., a gel point) under certain conditions can be printed using the automatic layer-by-layer deposition method. In fact, very few of them can be printed under various conditions (low temperature, without the help of physical, chemical, biochemical crosslinking of the incorporated polymer chains). Thus, not all natural polymers can meet all the basic requirements for 3D bioprinting. As a rule, natural polymers as the main component of various inks, which contain cells suspended in a specific medium, must meet several basic requirements for successful 3D bioprinting of organs, as well as clinical applications. These include biocompatibility, that is, non-toxic or without apparent toxicity; biodegradability (unlikenon-biodegradable polymers can be used as auxiliary structures); biostability with sufficiently high mechanical strength both at the time of processing and during operation; bioprinterness (workability). This review is devoted to modern research in the field of natural polymers used to print biological artificial organs.

Layer-by-Layer Thin Films of Alginate/Chitosan and Hyaluronic Acid/Chitosan with Tunable Thickness and Surface Roughness

2014 ◽  
Vol 783-786 ◽  
pp. 1226-1231 ◽  
Author(s):  
Thiago Bezerra Taketa ◽  
Marisa Masumi Beppu
Keyword(s):  
Thin Films ◽  
Hyaluronic Acid ◽  
Self Assembly ◽  
Polymer Chains ◽  
Layer By Layer ◽  
Natural Polymers ◽  
Force Microscopy ◽  
Atomic Force ◽  
Polyelectrolyte Solutions ◽  
Oppositely Charged

Layer-by-layer (LbL) is a bottom-up technique used for construction of films with self-assembly and self-organizing properties. In most cases, the fundamental driving force for the formation of these films is originated from the electrostatic interaction between oppositely charged species. The charged segments of polyelectrolytes behave as small building units and their orientation and position can be designed to target structures of great complexity. Furthermore, the technique enables the use of various materials, including natural polymers. In this work, we chose the cationic biopolymer chitosan (CHI) and the negative polyelectrolytes sodium alginate (ALG) and hyaluronic acid (HA). The aim of this study was to evaluate the effect of ionic strength (0 versus 200 mM) and pH (3 versus 5) on ALG/CHI and HA/CHI nanostructured multilayered thin films properties. From profilometry and atomic force microscopy (AFM) analyses, changes in thickness and roughness of the coatings were monitored. The presence of salt in polyelectrolyte solutions induced the polymer chains to adopt conformations with more loops and tails and this arrangement in solution was transmitted to films, resulting in rougher surfaces. Furthermore, the film thickness can be precisely controlled by adjusting the pH of the polyelectrolyte solution. The variation of these parameters shows that it is possible to molecularly control chemical and structural properties of nanostructured coatings, thus opening up new possibilities of application (e.g. cell adhesion).

Controlled surface functionality of magnetic nanoparticles by layer-by-layer assembled nano-films

Nanoscale ◽  
2015 ◽  
Vol 7 (15) ◽  
pp. 6703-6711 ◽  
Author(s):  
Daheui Choi ◽  
Boram Son ◽  
Tai Hyun Park ◽  
Jinkee Hong
Keyword(s):  
Magnetic Nanoparticles ◽  
Self Assembly ◽  
Carbon Materials ◽  
Synthetic Polymers ◽  
Layer By Layer ◽  
Natural Polymers ◽  
Surface Functionality ◽  
Assembly Method

We report the development of various functionalized MNPs (F-MNPs) generated using the layer-by-layer (LbL) self-assembly method. To provide broad functional opportunities, we fabricated F-MNP bio-toolbox by using three different materials: synthetic polymers, natural polymers, and carbon materials.

scholarly journals High performance free-standing films by layer-by-layer assembly of graphene flakes and ribbons with natural polymers

2016 ◽  
Vol 4 (47) ◽  
pp. 7718-7730 ◽  
Author(s):  
D. Moura ◽  
S. G. Caridade ◽  
M. P. Sousa ◽  
E. Cunha ◽  
H. C. Rocha ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
High Performance ◽  
Layer By Layer ◽  
Natural Polymers ◽  
Free Standing ◽  
Layer By Layer Assembly ◽  
Graphene Flakes ◽  
Layer Assembly

In this work, novel free-standing (FS) films based on chitosan, alginate and graphene oxide (GO) were developed through layer-by-layer assembly.

scholarly journals Overview of Current Advances in Extrusion Bioprinting for Skin Applications

2020 ◽  
Vol 21 (18) ◽  
pp. 6679
Author(s):  
Arantza Perez-Valle ◽  
Cristina Del Amo ◽  
Isabel Andia
Keyword(s):  
Extracellular Matrix ◽  
Early Stage ◽  
Signaling Proteins ◽  
Layer By Layer ◽  
Natural Polymers ◽  
Decellularized Extracellular Matrix ◽  
Stage Of Development ◽  
Extracellular Matrix Components ◽  
Biomimetic Approach ◽  
Cell Phenotypes

Bioprinting technologies, which have the ability to combine various human cell phenotypes, signaling proteins, extracellular matrix components, and other scaffold-like biomaterials, are currently being exploited for the fabrication of human skin in regenerative medicine. We performed a systematic review to appraise the latest advances in 3D bioprinting for skin applications, describing the main cell phenotypes, signaling proteins, and bioinks used in extrusion platforms. To understand the current limitations of this technology for skin bioprinting, we briefly address the relevant aspects of skin biology. This field is in the early stage of development, and reported research on extrusion bioprinting for skin applications has shown moderate progress. We have identified two major trends. First, the biomimetic approach uses cell-laden natural polymers, including fibrinogen, decellularized extracellular matrix, and collagen. Second, the material engineering line of research, which is focused on the optimization of printable biomaterials that expedite the manufacturing process, mainly involves chemically functionalized polymers and reinforcement strategies through molecular blending and postprinting interventions, i.e., ionic, covalent, or light entanglement, to enhance the mechanical properties of the construct and facilitate layer-by-layer deposition. Skin constructs manufactured using the biomimetic approach have reached a higher level of complexity in biological terms, including up to five different cell phenotypes and mirroring the epidermis, dermis and hypodermis. The confluence of the two perspectives, representing interdisciplinary inputs, is required for further advancement toward the future translation of extrusion bioprinting and to meet the urgent clinical demand for skin equivalents.

scholarly journals KARAKTERISASI FILM KOMPOSIT ALGINAT DAN KITOSAN

REAKTOR ◽  
2012 ◽  
Vol 14 (2) ◽  
pp. 158 ◽  
Author(s):  
Nur Rokhati ◽  
Bambang Pramudono ◽  
Nyoman Widiasa ◽  
Heru Susanto
Keyword(s):  
Composite Films ◽  
Raw Material ◽  
Layer By Layer ◽  
Permeability Test ◽  
Natural Polymers ◽  
Layer Method ◽  
Degree Of Swelling ◽  
Chitosan Films ◽  
Chitosan Composite

CHARACTERIZATION OF ALGINATE AND CHITOSAN COMPOSITE FILM. Due to the specific characteristics of (thin) films, the use of polymer films in various aplications has singnificantly increased. Alginate and chitosan are natural polymers, which have potential as a raw material for the manufacture of composite films. This paper presents the preparation and characterization of alginate, chitosan and chitosan-alginate composite films. The film characterization included permeability test, degree of swelling, mechanical property, morphology (by SEM), and surface chemistry (by FTIR). The results showed that alginate films have a higher permeability ​​and degree of swelling (DS) than chitosan films. Both permeability and DS decreased with increasing concentration for both alginate and chitosan films. DS experiments showed that the films have the highest DS in water followed by ethanol 95% and ethanol >99.9%, respectively. The mechanical strength of chitosan films was larger than alginate films. Alginate-chitosan composite films prepared by layer by layer method showed better characteristics than the composite films prepared by blending of alginate and chitosan solutions. Meningkatnya aplikasi film polimer di berbagai industri tidak terlepas dari keunggulan yang dimiliki. Alginat dan kitosan merupakan polimer alam yang mempunyai potensi sebagai bahan dasar pembuatan film komposit. Pada penelitian ini dilakukan pembuatan dan karakterisasi film komposit berbasis alginat dan kitosan. Karakterisasi film yang dilakukan meliputi uji: permeabilitas, derajat swelling, mekanik, morfologi (dengan SEM), dan struktur kimia permukaan (dengan FTIR). Hasil penelitian menunjukkan bahwa film alginat mempunyai nilai permeabilitas maupun derajat swelling yang lebih tinggi dibanding dengan film kitosan. Baik pada kitosan maupun alginat memberikan fenomena bahwa semakin besar konsentrasi larutan maka semakin kecil nilai permeabilitas maupun derajat swelling, dengan derajat swelling terhadap air adalah yang  paling besar kemudian diikuti oleh ethanol teknis (± 95%) dan yang terkecil adalah ethanol PA (> 99,9%). Kekuatan mekanik film kitosan lebih besar dibanding dengan film alginat. Film komposit alginat-kitosan yang dibuat dengan metode layer by layer memberikan karakteristik yang lebih baik dibanding dengan film komposit yang dibuat dengan pencampuran larutan alginat dan larutan kitosan.

scholarly journals Development of Multifunctional Coating of Textile Materials Using Silver Microencapsulated Compositions

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 159
Author(s):  
Luidmila Petrova ◽  
Olga Kozlova ◽  
Elena Vladimirtseva ◽  
Svetlana Smirnova ◽  
Anna Lipina ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Xanthan Gum ◽  
Correlation Spectroscopy ◽  
Biologically Active ◽  
Oyster Mushroom ◽  
Layer By Layer ◽  
Textile Materials ◽  
Hygroscopic Properties ◽  
Capsule Shell ◽  
Positively Charged

The efficiency of the method for the synthesis of silver nanoparticles using a system containing oxalic dialdehyde as a reducing agent, and polyguanidine as a stabilizer is shown. An analysis of the data of photon correlation spectroscopy characterizing the sizes of the formed particles in the Ag-polyelectrolyte system is presented. It has been established that the synthesized silver nanoparticles have a stable biocidal effect. The system of biodegradable polyelectrolytes chitosan-xanthan gum for the synthesis of the capsule shell including silver nanoparticles is selected. This will allow the formation of stable polyelectrolyte capsule shells containing oyster mushroom mycelium extract. A protocol for the synthesis of microcapsules by the method of sequential adsorption of chitosan polyelectrolytes and xanthan gum on calcium carbonate templates was developed. Silver nanoparticles are included in the capsule shell, and a biologically active drug (oyster mushroom mycelium extract) is included in the core. The technological mode of complex capsules immobilization on a textile material by the layer-by-layer method is described. The immobilization of multilayer microcapsules on a fibrous substrate is provided by a system of polyelectrolytes: positively charged chitosan and negatively charged xanthan gum. The developed multifunctional coatings make it possible to impart multifunctional properties to textile materials: antibacterial, antimycotic, high hygroscopic properties.

Sign in / Sign up

Export Citation Format

Share Document