Preparation and test of a reference mixture of eleven polymers with deactivated inorganic diluent for microplastics analysis by pyrolysis-GC–MS

2021 ◽  
Vol 154 ◽  
pp. 104993
Author(s):  
Mai Matsueda ◽  
Marco Mattonai ◽  
Itsuko Iwai ◽  
Atsushi Watanabe ◽  
Norio Teramae ◽  
...  
Keyword(s):  
Reference Mixture

scholarly journals Making Paving Stones from Copper Mine Tailings as Aggregates

2020 ◽  
Vol 17 (7) ◽  
pp. 2448 ◽  
Author(s):  
Elizabeth J. Lam ◽  
Vicente Zetola ◽  
Yendery Ramírez ◽  
Ítalo L. Montofré ◽  
Franco Pereira
Keyword(s):  
Compression Strength ◽  
Mine Tailings ◽  
Bending Strength ◽  
Copper Mining ◽  
Fines Content ◽  
Concrete Aggregates ◽  
Copper Mine Tailings ◽  
Tailings Dams ◽  
Sieve Size ◽  
Reference Mixture

Copper mining, the central axis of Chile’s economic development, produces a large number of tailings, which become a potential environmental risk. This study aims to evaluate the mechanical properties resulting from the making of Portland cement mixtures with tailings as aggregates so that they can be eventually used in paving stones for building inactive tailings dams. Tailings coming from two dams at a concentration plant located in Taltal (Chile) were used. Currently, Dam 1 is inactive, while Dam 2 is active. The tailings samples obtained from both dams were granulometrically characterized by sieving. In addition, pH, humidity, Eh, and mineralogical assays (sulfides, oxides, sulfates, carbonates, phosphates, and silicates) were measured. The fines content of the tailings from Dams 1 and 2 with a sieve size of N°200 ASTM were 76.2% and 29.6%, respectively. Therefore, owing to their high percentage of fines, they cannot be as used as concrete aggregates. Aggregates must contain a maximum percentage of fines so that mortars and concrete can meet Chilean standards. In this paper, to comply with a 7% and 15% fines content lower than 0.075 mm, tailings materials were mixed with conventional aggregates containing very little fines. In addition, a reference mixture was made with only tailings aggregates with and without a superplasticizer additive. To measure the mixtures of cement, aggregates, and tailings, bending and compression strength assays were made of the specimens after a 28-day curing, according to the Chilean standard. The results of the study show that the addition of only part of the tailings to the mixture increases bending strength by 26% and compression strength by 180% compared with the reference mortar, with a fines content lower than 0.075 mm in the 7% mixture, thus allowing paving stone manufacture with tailings materials. In addition, it was possible to increase the workability of the reference mixture by using superplasticizers as additives.

scholarly journals Investigation of the Potential Use of Curauá Fiber for Reinforcing Mortars

Fibers ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 69
Author(s):  
Afonso R. G. de Azevedo ◽  
Sergey Klyuev ◽  
Markssuel T. Marvila ◽  
Nikolai Vatin ◽  
Nataliya Alfimova ◽  
...  
Keyword(s):  
Water Retention ◽  
Natural Fibers ◽  
Northern Region ◽  
Technological Properties ◽  
Wetting And Drying ◽  
Air Content ◽  
Naoh Solution ◽  
Potential Use ◽  
Reference Mixture ◽  
Curauá Fiber

Curauá is a bromeliad of Amazonian origin, present in some states in the northern region of Brazil and in other countries in South America. Its natural fibers have several technological advantages for application in composite materials. The objective of this research was to investigate the potential of using the fiber of Curauá as a reinforcement element in mortars for wall covering. Mortars were made with a 1:1:6 ratio (cement:lime:sand) in relation to their mass, evaluating the effect of adding 1%, 2% and 3% of Curauá fiber natural and fiber treated in NaOH solution in relation to the mass of cement, compared to the reference mixture (0%). Technological properties such as consistency, water retention and incorporated air content, compressive strength, water absorption and durability in wetting and drying cycles were evaluated. The results showed that the addition of the Curauá fiber causes an improvement in the mechanical properties of mortars, and at levels of addition 3% or more, it causes problems of workability and incorporation of air into the dough, thus, the fiber addition in 2% presented better results for application in coating mortars, in relation a Brazilian norm, even improving the durability of external coatings.

scholarly journals The Influence of a Polymer Powder on the Properties of a Cold-Recycled Mixture with Foamed Bitumen

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4244 ◽  
Author(s):  
Przemysław Buczyński ◽  
Marek Iwański
Keyword(s):  
Physical And Mechanical Properties ◽  
Void Content ◽  
Reclaimed Asphalt Pavement ◽  
Reclaimed Asphalt ◽  
Polymer Powder ◽  
Varied Chemical ◽  
Foamed Bitumen ◽  
Powder Type ◽  
Air Void ◽  
Reference Mixture

The paper investigates the influence of redispersible polymer powder (RPP) on the physical and mechanical properties of a cold-recycled mixture with foamed bitumen (CRM-FB). Four types of RPP with a varied chemical base were used: VA-VeoVA, VA-VeoVa-Ac, EVA and VA/VV/E/Ac. The polymer powder-modified cold recycled mixture with foamed bitumen, (P)CRM-FB, was composed of 45.8% reclaimed asphalt pavement (RAP), 45.8% natural aggregate (VA), 3.0% Portland cement CEM I 42,5R, 3.0% foamed bitumen 50/70 and 3.0% RPP, all dosed by weight. The reference mixture, (R)CRM-FB, served as a reference point for comparison. It was found that RPP improved the workability of the CRM-FB mixture. This results in a reduced number of compaction cycles and lower energy needed to obtain the air void content as in the reference mixture. In addition, the RPP modifier markedly increased the CRM-FB mixture cohesion (ITSDRY) and strength, by approximately 40–70%, depending on the RPP used. These findings are particularly important for CRM-FB mixtures designed for road bases. The present investigations confirmed the improvement of the CRM-FB mixture parameters after the modification with RPP, regardless of the powder type used.

scholarly journals Design of alkali-activated materials for a modular green wall and green roof system

2019 ◽  
Vol 274 ◽  
pp. 04001
Author(s):  
Maria Manso ◽  
João Castro-Gomes
Keyword(s):  
Compressive Strength ◽  
Mine Waste ◽  
Green Roof ◽  
Strength Loss ◽  
Capillary Absorption ◽  
Green Wall ◽  
Roof System ◽  
Density Reduction ◽  
Alkali Activated ◽  
Reference Mixture

This study presents the work developed with alkali activated mixtures to be used as component of a new modular green wall and green roof system (GEOGREEN). The aim is to find the most appropriate composition of alkali-activated mixture to maximize water absorption and porosity and also find a good mechanical strength with reduced density. Alkali-activated mixtures were produced using two precursors, mine waste mud from Panasqueira mine (W) and ground waste glass (G) and two alkaline activators, sodium silicate (SS) and sodium hydroxide (SH). A ventilated oven was used to speed up the curing process. Variables as percentage substitution of W per G, molar concentration of SH, cure length and temperature, were tested to identify the reference mixture. After these tests different percentages of aggregates as sand (S), expanded cork granules (C) and expanded clay (A) were added to reference mixture (REF). Results indicate that S25 obtained the maximum compressive strength of 35 MPa after 7 curing days. However, about 30% compressive strength loss is observed after immersion of this mixture in water for 24h. Capillary absorption coefficient can reach to 4,77 kg/m2.h0,5 with C25 and to 4,11 kg/m2.h0,5 with S25. Also C50 enables a 20% density reduction compared to REF.

Effect of Calcined Red Mud Addition on the Hydration of Portland Cement

2012 ◽  
Vol 727-728 ◽  
pp. 1408-1411 ◽  
Author(s):  
Daniel Véras Ribeiro ◽  
João A. Labrincha ◽  
Márcio Raymundo Morelli
Keyword(s):  
Portland Cement ◽  
Red Mud ◽  
Setting Time ◽  
Cementitious Materials ◽  
Adiabatic Calorimeter ◽  
Hydration Process ◽  
Early Hydration ◽  
Bauxite Ore ◽  
Calorimetric Studies ◽  
Reference Mixture

The red mud (RM) is a solid waste derived from the processing of bauxite ore to produce alumina and it is considered a hazardous waste due to its high pH. This paper describes the use of mud untreated and after calcination at distinct temperatures (450, 650, and 1000°C) attempting to improve its reactivity. The Portland cement was replaced up to 30 wt% red mud, and its addition changed the hydration process, evaluated by calorimetric studies of early hydration and setting time. By comparing with the reference mixture (without red mud), the obtained results confirm the potential of the red mud to be used as pozzolanic additive to cementitious materials. Temperature of hydration was monitored by a quasi-adiabatic calorimeter (Langavant). The hydration temperature increases with RM addition, particularly if calcined in the same interval (450-650°C). In this condition, the hydration process is accelerated.

Study of Road Property of Basalt Fiber Asphalt Concrete

2012 ◽  
Vol 238 ◽  
pp. 22-25 ◽  
Author(s):  
Yuan Zhao Chen ◽  
Zhen Xia Li
Keyword(s):  
Asphalt Concrete ◽  
Asphalt Mixture ◽  
Basalt Fiber ◽  
Temperature Stability ◽  
Asphalt Mixtures ◽  
Polyester Fiber ◽  
Pavement Performance ◽  
High Temperature Stability ◽  
Reference Mixture ◽  
Temperature Crack

In order to discuss the effectiveness of basalt fiber in reinforcing pavement performance of asphalt mixtures, the pavement performances of basalt fiber asphalt mixtures were investigated by tests of high temperature stability, water stability and low temperature crack resistance, and compared with the pavement performance of asphalt mixtures with polyester fiber and xylogen fiber, and that of reference mixture. The results show that pavement performance of fiber asphalt mixture are improved and optimized comparing with reference asphalt mixture, the performance of asphalt mixture with basalt fiber are excelled than those with polyester fiber and xylogen fiber while the dosage of fibers is keeping at the optimum.

scholarly journals Molecular Nearest Neighbors Determine Generalization of Odorant Mixtures

2018 ◽  
Author(s):  
Ryan J. Brackney ◽  
Kael Dai ◽  
Taleen Der-Ghazarian ◽  
Brian H. Smith ◽  
Richard C. Gerkin
Keyword(s):  
Binary Mixtures ◽  
Olfactory System ◽  
Nearest Neighbor ◽  
Behavioral Responses ◽  
Nearest Neighbors ◽  
Perceptual Quality ◽  
Perceptual Similarity ◽  
Test Mixture ◽  
Formal Principle ◽  
Reference Mixture

ABSTRACTMost natural odors arise from mixtures of multiple odorants. Some such mixtures are perceived “elementally”, with each odorant component clearly identifiable, while others are perceived “configurally”, with the mixture adopting a perceptual quality distinct from any of the components. While the perceptual similarity of two mixtures is presumably related in some way to the similarity of the corresponding components, given the elemental/configural dichotomy it is unclear if any formal principle can be used to predict mixture similarity. To investigate this problem, we trained mice to respond to a binary reference mixture of structurally similar odorants (S+) and then tested generalization of this response to other structurally related binary test mixtures. Across 5 experiments, we parametrically varied these mixtures in distinct ways to test candidate models for the perceptual similarity of mixtures. The best-performing model predicted behavioral responses by considering, for each component of the S+, only the similarity of the most structurally similar (”nearest neighbor”) component of each test mixture. We conclude that for mixture generalization tasks the olfactory system may deemphasize or discard information about mixture components not perceptually “near” enough to any of those in the S+, consistent with a sparse and elemental rule for perception of structurally-related binary mixtures.

Dynamic Stability of Multi-Functional Composite Developed for Application in Permanent Way of Prague Underground

2018 ◽  
Vol 760 ◽  
pp. 147-151
Author(s):  
Karel Kolář ◽  
Jiří Litoš ◽  
Pavel Reiterman ◽  
Miroslav Petrtýl
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Dynamic Stability ◽  
Dynamic Loading ◽  
Rapid Evolution ◽  
Steel Fibers ◽  
Laboratory Model ◽  
Transportation Industry ◽  
Reference Mixture

There are described properties of hardening multi-functional silicate composite during its long-term dynamical loading in the paper. Studied composite was developed for special application in permanent way structure in Prague underground. Dynamic loading was carried out on the laboratory model, in which the composite was applied as a bench of the rail anchoring. Due to loading in early ages was also studied the option of steel fibers addition. Results obtained confirmed impressive potential for practical use during new tracks construction, and quick repairs as well, because of rapid evolution of mechanical properties and sufficient resistance to dynamic loading. Silicate composite with fibers addition had better mechanical properties, however significant improvement during dynamic loading was not recorded in comparison with the reference mixture without fibers. Generally, new composite material confirmed great potential for practical use in transportation industry.

scholarly journals Pervious concrete: study of dosage and polypropylene fibers addiction

2019 ◽  
Vol 12 (1) ◽  
pp. 101-121 ◽  
Author(s):  
S. E. PILS ◽  
P. OLIVEIRA ◽  
F. REGOSO ◽  
V. A. PAULON ◽  
M. F. COSTELLA
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Permeability Coefficient ◽  
Main Property ◽  
Pervious Concrete ◽  
Polypropylene Fibers ◽  
Design And Implementation ◽  
Reference Mixture

Abstract The use of pervious concrete to minimize the effects caused by the impermeability of the soil as a result of increasing urbanization is an alternative that still requires further studies regarding its design and implementation. From this perspective, this paper presents a study of the characteristics of pervious concrete, including its tensile strength, compressive strength, flexural strength and the permeability coefficient, through the development of various mixtures to adjust the characteristics of the local aggregates. Eight mixtures were studied based on a reference mixture, five of which were related to the pervious concrete with the addition of finer aggregates than the reference mixture without these aggregates. Subsequently, three mixtures were studied with the inclusion of polypropylene fibers in order to analyze the effects of the addition of fibers on the properties of the pervious concrete. It is concluded that the presence of fibers changed the characteristics of the concrete, increasing its strengths while achieving a good permeability in its mixtures. An improvement in the flexural strength of the pervious concrete was observed, which is the main property to be considered for its use in pavements, without harming the permeability, which raises the possibility for its application.

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