scholarly journals Recycled Waste Powders for Alkali-Activated Paving Blocks for Urban Pavements: A Full Laboratory Characterization

2019 ◽  
Vol 4 (4) ◽  
pp. 73 ◽  
Author(s):  
Piergiorgio Tataranni

Paving blocks are today a popular paving solution for urban surfaces. Considering the wide variety of products currently on the market, it is possible to build pavements that differ in terms of functionality, bearing capacity, skid resistance, visual impact, and aesthetic integration with the surrounding landscape. Interlocking concrete paving block is the most common construction technology considering its low cost and its easy installation. Different wastes and second-hand materials have recently been tested in order to completely or partially replace the raw materials used for the production of paving blocks. In this paper, a waste basalt powder is used for the production of alternative paving blocks through the alkali-activation process. Two different synthetic blocks were produced, with and without aggregates. Taking into account the EN 1338 standard for concrete paving blocks, a complete laboratory characterization is proposed for the two experimental blocks. Tests highlighted positive results and downsides that need to be optimized in order to convert the laboratory production to an industrial scale.

Membranes ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 105 ◽  
Author(s):  
Amanmyrat Abdullayev ◽  
Maged Bekheet ◽  
Dorian Hanaor ◽  
Aleksander Gurlo

In water treatment applications, the use of ceramic membranes is associated with numerous advantages relative to polymer-based filtration systems. High-temperature stability, fouling resistance, and low maintenance requirements contribute to lower lifecycle costs in such systems. However, the high production costs of most commercially available ceramic membranes, stemming from raw materials and processing, are uneconomical for such systems in most water treatment applications. For this reason, there is a growing demand for new ceramic membranes based on low-cost raw materials and processes. The use of unrefined mineral feedstocks, clays, cement, sands, and ash as the basis for the fabrication of ceramic membranes offers a promising pathway towards the obtainment of effective filtration systems that can be economically implemented in large volumes. The design of effective ceramic filtration membranes based on low-cost raw materials and energy-efficient processes requires a balance of pore structure, mass flow, and robustness, all of which are highly dependent on the composition of materials used, the inclusion of various pore-forming and binding additives, and the thermal treatments to which membranes are subjected. In this review, we present recent developments in materials and processes for the fabrication of low-cost membranes from unrefined raw materials, including clays, zeolites, apatite, waste products, including fly ash and rice husk ash, and cement. We examine multiple aspects of materials design and address the challenges relating to their further development.


2021 ◽  
Vol 37 ◽  
pp. e37078
Author(s):  
José Vaz Pinheiro Neto

Biodiesel is a clean and cyclical energy resource that is derived from animal and/or vegetable fat. As it blends well with petrodiesel, biodiesel is added to Brazilian commercial diesel. The main raw materials used to produce biodiesel in Brazil include soybean, corn, and sunflower oils. However, these are also used for human consumption and hence, have a high market value. Therefore, pinhão manso oil, which exhibits high productivity at low cost, is a promising alternative. However, the high acidity index of this oil results in a low transesterification yield and the produced biofuel does not meet the requirements imposed by the ANP. Thus, this study intends to demonstrate that a large part of the free fatty acids in pinion oil are present in the seed endocarp. For the development of the project, the oil was extracted by hot solvent, using the soxhlet equipment and the hexane solvent, to determine the acidity index, the titration technique was used, the titrant used was sodium hydroxide. So the acidity index of the oil extracted from the seed with its shell is 10.9 mgKOH/g, while the lipid obtained without the shell exhibits a value of 0.95 mgKOH/g, proving the influence of the endocarp.


Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2284
Author(s):  
Bartolomeo Coppola ◽  
Jean-Marc Tulliani ◽  
Paola Antonaci ◽  
Paola Palmero

This review aims to provide a comprehensive assessment concerning alkali activation of natural stone wastes and minerals. In particular, the structure of the review is divided into two main sections in which the works dealing with alumino-silicate and carbonatic stones are discussed, respectively. Alumino-silicate stones are generally composed of quartz and feldspars, while carbonatic stones are mainly made of calcite and dolomite. The role of these minerals in the alkali activation process is discussed, attesting their influence in the development of the final product properties. In most of the works, authors use mineral additions only as fillers or aggregates and, in some cases, as a partial substitution of more traditional raw powders, such as metakaolin, fly ash, and granulated blast furnace slag. However, a few works in which alumino-silicate and carbonatic stone wastes are used as the main active components are discussed as well. Not only the raw materials, but also the entire alkali activation process and the curing conditions adopted in the literature studies here reviewed are systematically analyzed to improve the understanding of their effect on the physical, mechanical, and durability properties of the final products and to eventually foster the reuse of natural stone wastes for the purposes of sustainability in different applications.


Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 197
Author(s):  
Jozef Vlček ◽  
Michaela Topinková ◽  
Miroslava Klárová ◽  
Petra Maierová ◽  
Hana Ovčačíková ◽  
...  

Metakaolin (MK) prepared by the calcination of kaolin at 550 °C and fly ash (FA) from the combustion of black coal in a granulating boiler were used to prepare unfired ceramic bonding systems via the alkali activation process. A long-term stability of the mechanical properties of the prepared samples similar to the unfired ceramic systems was observed. The optimal metakaolin and fly ash ratio, the type of the activator (NaOH or water glass) and its concentration were evaluated after the hydration in: a) laboratory conditions; b) hydration box; and c) under the hydrothermal activation. Raw materials and the samples prepared by alkali activation process were characterized by XRD, XRF, TG/DTA, and FTIR methods. The mechanical properties of the prepared samples were tested using a compressive strength test after 2, 28 and 56 days of hydration. The compressive strengths of 16 and 24 MPa after 28 days of hydration were reached for FA samples activated with water glass. The alkali activation of MK was successful in the NaOH solution of the molar concentration above 5 M. The compressive strength values of metakaolin, activated hydrothermally and hydrated at laboratory conditions, reached 11.2 and 5.5 MPa, respectively, for 5 M activator of NaOH.


Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3563 ◽  
Author(s):  
Barbara Horvat ◽  
Vilma Ducman

The aim of the paper is to research the influence of foaming and stabilization agents in the alkali activation process of waste green ceramics for future low cost up-cycling into lightweight porous thermal insulating material. Green waste ceramics, which is used in the present article, is a green body residue (non-successful intermediate-product) in the synthesis of technical ceramics for fuses. This residue was alkali activated with Na-water glass and NaOH in theoretically determined ratio based on data from X-ray fluorescence (XRF) and X-ray powder diffraction (XRD) that was set to maximise mechanical properties and to avoid efflorescence. Prepared mixtures were compared to alkali activated material prepared in theoretically less favourable ratios, and tested on the strength and density. Selected mixtures were further foamed with different foaming agents, that are Na-perborate (s), H2O2 (l), and Al (s), and supported by a stabilization agent, i.e., Na-dodecyl sulphate. The goal of the presented work was to prepare alkali activated foam based on green ceramics with density below 1 kg/l and compressive strength above 1 MPa.


2019 ◽  
Vol 8 (3) ◽  
pp. 8349-8353

The ultimate source of energy for crucial activities like cooking, heating and parboiling process is burning wood and other agricultural products. Due to growing populations utilizing resource of combustible biomass materials will finally result in insufficiency of those materials until certain measures are taken to secure them. It mainly focuses on the minimization of pollution especially land, water and air and to avoid the deforestation mainly for many fuels for burning. The product taken is the by-product, which is obtained from the residue left after letting the cotton industrial waste for reuse. The raw materials used are cassava waste, coconut shell, groundnut shell, cotton waste and cow dung with thirty different mix ratios. The briquettes were made without using any binder. Using hydraulic pressure with UTM given to produce the briquettes are 5.0 kN/cm 2 , 5.6 kN/cm2 and 6.0 kN/cm2 . Good energy content has been obtained when the pressure for producing briquettes at 5.6 kN/cm2 .These briquettes are mainly used for industrial boiler running and cooking purpose.


Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2039 ◽  
Author(s):  
Hongbo Chen ◽  
Jingjing Wang ◽  
Yaohua Cheng ◽  
Chuansheng Wang ◽  
Haichao Liu ◽  
...  

As the IV generation of packaging, biopolymers, with the advantages of biodegradability, process ability, combination possibilities and no pollution to food, have become the leading food packaging materials. Biopolymers can be directly extracted from biomass, synthesized from bioderived monomers and produced directly by microorganisms which are all abundant and renewable. The raw materials used to produce biopolymers are low-cost, some even coming from agrion dustrial waste. This review summarized the advances in protein-based films and coatings for food packaging. The materials studied to develop protein-based packaging films and coatings can be divided into two classes: plant proteins and animal proteins. Parts of proteins are referred in this review, including plant proteins i.e., gluten, soy proteins and zein, and animal proteins i.e., casein, whey and gelatin. Films and coatings based on these proteins have excellent gas barrier properties and satisfactory mechanical properties. However, the hydrophilicity of proteins makes the protein-based films present poor water barrier characteristics. The application of plasticizers and the corresponding post-treatments can make the properties of the protein-based films and coatings improved. The addition of active compounds into protein-based films can effectively inhibit or delay the growth of microorganisms and the oxidation of lipids. The review also summarized the research about the storage requirements of various foods that can provide corresponding guidance for the preparation of food packaging materials. Numerous application examples of protein-based films and coatings in food packaging also confirm their important role in food packaging materials.


2005 ◽  
Vol 500-501 ◽  
pp. 471-480 ◽  
Author(s):  
Michael Korchynsky

The recent worldwide surge of steel consumption, mainly of low-strength carbon grades, has created raw-materials shortages and price increases. These supply-demand strains could be relaxed by satisfying engineering needs with less steel. However, materials used for such a substitution must combine high weight reducing potential with low cost. Microalloyed (MA) steels are cost- effective substitutes, since their high strength is the result of grain refinement and precipitation hardening. The optimum alloy design of MA steels combines superior properties with lowest processing cost. The growing use of EAF and thin slab casting technology improve the economics of MA steels, especially when alloyed with vanadium. The monetary value of weight reduction is sufficient to increase the profitability of steel makers and to lower the material cost to steel users. This “win-win” situation is financed by the elimination of efforts spent in producing inefficient steel, yielding an increase in wealth formation. To gain acceptance of substitution by the consumer, a long-term strategic plan is needed to be implemented by the beneficiaries – steel producers and steel users. The successful substitution is of importance to the national economy, resources and energy conservation, and the environment. Since microalloyed steels, used as a replacement for carbon steels, offer low-cost weight savings, they deserve to be classified as advanced structural materials.


2018 ◽  
Vol 67 ◽  
pp. 04035 ◽  
Author(s):  
Dewi Tristantini ◽  
Cindy Sandra

Cellulose acetate is a natural polymer, that is widely used in various industries, especially fiber and plastics. Cellulose acetate was created by an esterification reaction of cellulose and acetic anhydride. The raw materials used in this research were empty fruit bunches of palm oil and dried jackfruit leaves, because utilization of waste, available in large quantities, and contain high cellulose. The objective of this study was to obtain high yield cellulose and cellulose acetate from palm oil bunches and jackfruit leaves. This was done by variating delignification time, bleaching time, and acetylation time. Cellulose isolation was performed through a delignification process by adding NaOH and bleaching process by adding H2O2. The optimum yield for the empty palm oil bunches cellulose was 36.45%, with the delignification time of 1.5 hours and the bleaching time of 30 minutes. The optimum yield of jackfruit leaves cellulose was 13.72%, with 1-hour delignification time and 30 minutes bleaching time. Cellulose acetate was obtained by cellulose activation process by adding acetic acid glacial, acetylation process with anhydrous acetate, and hydrolysis with water. The yield of cellulose acetate obtained was 81.75% for palm oil bunches and 63.89 for jackfruit leaves.


2020 ◽  
Vol 8 (5) ◽  
pp. 187-193
Author(s):  
Francisco de A. Ribeiro Filho ◽  
Fernando B. Mainier ◽  
Luciane P. Costa Monteiro

Glycerin is a by-product of the transesterification reaction of vegetable oil to produce biodiesel. Glycerin production has increased as the number of biodiesel industries has grown. With features such as water solubility, low cost, and non-toxicity, it is a good substance for water-based drilling fluid formulations with less environmental contamination. The experiments were conducted using a drilling fluid commonly used in Brazil and were compared with glycerin additions at concentrations of 5, 10, 15, and 20% by volume. Considering that as a result of the raw materials used, the biodiesel production routes produce a contaminated glycerin, it was decided to use a bi-distilled glycerin. In addition, sodium silicate, which uses industrial water or seawater, was added as a corrosion inhibitor due to its good performance and environmental non-toxicity. The sodium silicate was effective in combating corrosion without interfering with the fluid properties. The values of plastic viscosity, yield point, L3 (reading 3 rpm), and gel strength, mostly presented results equal to or better than the original formulation of the fluid used as a comparison.


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