Radionuclide concentration and radon exhalation in new mix design of bricks produced reusing NORM by-products: The influence of mineralogy and texture

2020 ◽  
Vol 260 ◽  
pp. 119820
Author(s):  
Chiara Coletti ◽  
Erika Brattich ◽  
Giorgia Cinelli ◽  
Giuseppe Cultrone ◽  
Lara Maritan ◽  
...  
Keyword(s):  
Mix Design ◽  
Radionuclide Concentration ◽  
Radon Exhalation ◽  
By Products

scholarly journals Mortars with Recycled Aggregates from Building-Related Processes: A ‘Four-Step’ Methodological Proposal for a Review

2021 ◽  
Vol 13 (5) ◽  
pp. 2756
Author(s):  
Federica Vitale ◽  
Maurizio Nicolella
Keyword(s):  
Building Materials ◽  
Thermal Analyses ◽  
Construction Materials ◽  
Physical And Mechanical Properties ◽  
Research Trends ◽  
Mix Design ◽  
Recycled Aggregates ◽  
Design Parameters ◽  
Natural Aggregates ◽  
By Products

Because the production of aggregates for mortar and concrete is no longer sustainable, many attempts have been made to replace natural aggregates (NA) with recycled aggregates (RA) sourced from factories, recycling centers, and human activities such as construction and demolition works (C&D). This article reviews papers concerning mortars with fine RA from C&D debris, and from the by-products of the manufacturing and recycling processes of building materials. A four-step methodology based on searching, screening, clustering, and summarizing was proposed. The clustering variables were the type of aggregate, mix design parameters, tested properties, patents, and availability on the market. The number and the type of the clustering variables of each paper were analysed and compared. The results showed that the mortars were mainly characterized through their physical and mechanical properties, whereas few durability and thermal analyses were carried out. Moreover, few fine RA were sourced from the production waste of construction materials. Finally, there were no patents or products available on the market. The outcomes presented in this paper underlined the research trends that are useful to improve the knowledge on the suitability of fine RA from building-related processes in mortars.

scholarly journals Mixture Optimization of Concrete Paving Blocks Containing Waste Silt

2022 ◽  
Vol 14 (1) ◽  
pp. 451
Author(s):  
Abbas Solouki ◽  
Piergiorgio Tataranni ◽  
Cesare Sangiorgi
Keyword(s):  
Construction Materials ◽  
Physical And Mechanical Properties ◽  
Mix Design ◽  
Waste Materials ◽  
Skid Resistance ◽  
Washing Process ◽  
Different Types ◽  
New Construction ◽  
Tensile Splitting Strength ◽  
By Products

Most of the waste materials recycled for the production of new construction materials are by-products of various manufacturing processes, such as the aggregate washing process. Recycling such materials is of paramount importance since it could reduce the adverse environmental impacts resulting from landfilling. Various studies have attempted to recycle different types of waste materials and by-products into concrete paving blocks. However, the availability of literature on concrete paving blocks containing waste silt is quite scarce. Thus, the current paper focuses on mix design optimization and production of concrete paving blocks containing high amounts of waste silt resulting from the aggregate production process. Using the mixture Design of Experiments (DOE), 12 sets of concrete paving blocks with different aggregate blends were produced to optimize the mix design. Once the final mix design was achieved, the physical and mechanical properties of the concrete paving blocks were investigated following the EN 1338 standard. Shape and dimension measurements and various tests, including water absorption, tensile splitting strength, abrasion resistance, and slip/skid resistance were conducted on the experimental concrete paving samples. Overall, the produced concrete paving blocks showed promising properties for future applications in pedestrian walking paths.

A Review on Fly Ash as a Raw Cementitious Material for Geopolymer Concrete

2018 ◽  
Vol 69 (7) ◽  
pp. 1661-1667 ◽  
Author(s):  
Aissa Bouaissi ◽  
Long Yuan Li ◽  
Ligia Mihaela Moga ◽  
Ioan Gabriel Sandu ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
...  
Keyword(s):  
Fly Ash ◽  
Physical Properties ◽  
Review Paper ◽  
Chemical Activation ◽  
Solid Wastes ◽  
Mix Design ◽  
Chemical Compositions ◽  
Materials Used ◽  
By Products ◽  
Made In

This paper presents a review on fly ash as prime materials used for geopolymer. Due to its advantages of abundant resources, less in cost, great workability and high physical properties which lead to achieve high mechanical properties. Fly ash is considered as one of the largest generated industrial solid wastes or so-called industrial by products, around the world particularly in China, India and USA. The characteristics of fly ash allow it to be a geotechnical material to produce geopolymer cement or concrete as an alternative of Ordinary Portland cement. Many efforts are made in this direction to formulate a suitable mix design of fly ash based-geopolymer by focusing on fly ash as the main prime material. The physical properties, chemical compositions and chemical activation of fly ash are analysed and evaluated in this review paper. Reference has been made to different ASTM, ACI standards and other researches work in geopolymer area.

The Mix Design of Low Strength High Flowing Concrete with Low Cement Content Prepared by Manufactured Sand

2011 ◽  
Vol 413 ◽  
pp. 201-206
Author(s):  
Zhan Ao Liu ◽  
Ming Kai Zhou ◽  
Xiao Chen
Keyword(s):  
Cement Content ◽  
Design Method ◽  
Chloride Ion ◽  
Mix Design ◽  
Ion Diffusion ◽  
Natural Sand ◽  
Manufactured Sand ◽  
Low Strength ◽  
Chloride Ion Diffusion ◽  
By Products

Aiming at the engineering status of the shortage of natural sand and the contradictory between workability and strength surplus emerging in the design of low strength high flowing concrete (LHC), this paper has proposed a mix design method of LHC with low cement content prepared by manufactured sand (MS).And then verifies the feasibility of the method through experiments. Tests on slump, compressive strength and chloride ion diffusion coefficient were carried out and the results indicate that LHC with low cement content prepared by MS can be successfully produced using this method. Concrete designed by this method has low cement consumption and has utilized MS to replace NS as well as made full use of the industrial by-products of stone fines and fly ash. As a result, it is economical and ecological.

Hydrogen Cyanide Polymers from the Impact of Comet P/Shoemaker-Levy 9 on Jupiter

1997 ◽  
Vol 161 ◽  
pp. 179-187
Author(s):  
Clifford N. Matthews ◽  
Rose A. Pesce-Rodriguez ◽  
Shirley A. Liebman
Keyword(s):  
Amino Acids ◽  
Solar System ◽  
Hydrogen Cyanide ◽  
Nitrogen Heterocycles ◽  
Laboratory Studies ◽  
Heterogeneous Solids ◽  
The Many ◽  
Comet Halley ◽  
The Impact ◽  
By Products

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.

Bright-Field Images (Ctem) of Phase Objects at High Resolution

1976 ◽  
Vol 34 ◽  
pp. 490-491 ◽  
Author(s):  
Sumio Iijima
Keyword(s):  
High Resolution ◽  
Electron Beam Irradiation ◽  
Fine Particles ◽  
High Resolution Electron Microscopy ◽  
Good Test ◽  
Resolution Electron ◽  
Single Crystal Films ◽  
Crystal Films ◽  
By Products ◽  
Test Objects

We have developed a technique to prepare thin single crystal films of graphite for use as supporting films for high resolution electron microscopy. As we showed elsewhere (1), these films are completely noiseless and therefore can be used in the observation of phase objects by CTEM, such as single atoms or molecules as a means for overcoming the difficulties because of the background noise which appears with amorphous carbon supporting films, even though they are prepared so as to be less than 20Å thick. Since the graphite films are thinned by reaction with WO3 crystals under electron beam irradiation in the microscope, some small crystallites of WC or WC2 are inevitably left on the films as by-products. These particles are usually found to be over 10-20Å diameter but very fine particles are also formed on the film and these can serve as good test objects for studying the image formation of phase objects.

Sign in / Sign up

Export Citation Format

Share Document