scholarly journals Abrasive Wear Resistance of Concrete in Connection with the Use of Crushed and Mined Aggregate, Active and Non-Active Mineral Additives, and the Use of Fibers in Concrete

2020 ◽  
Vol 12 (23) ◽  
pp. 9920
Author(s):  
Lenka Bodnárová ◽  
Martin Ťažký ◽  
Lucia Ťažká ◽  
Rudolf Hela ◽  
Ondřej Pikna ◽  
...  
Keyword(s):  
Abrasion Resistance ◽  
Age Groups ◽  
High Strength ◽  
Mineralogical Composition ◽  
Concrete Mixtures ◽  
Standard Procedures ◽  
Different Types ◽  
The Impact ◽  
Mineral Additives ◽  
Active Mineral Additives

Virtually every concrete structure comes into contact with abrasive effects of flowing media or solids, which have a direct impact on the durability of concrete. An abrasive effect is most pronounced in transport or water management structures, and these structures are often designed for a significantly longer service life (usually 100 years). This research evaluates the influence of the filler component in terms of the type of aggregate and its mineralogical composition on concrete abrasion resistance. As part of the impact of the binder component, several concrete mixtures were produced using the same aggregate and maintaining the same strength class with the addition of different types of active and inert mineral additives. In other parts of the research, the effect of adding fiber reinforcement on the abrasion resistance of concrete was verified. Mutual connections and correlations in different age groups (7, 28 and 90 days) were sought for all obtained results. The abrasion resistance of the composite was monitored by using standard procedures, especially using a Böhm device. It was found that for good abrasion resistance of concrete, it is not necessary to produce concretes with high strength classes using often expensive mineral additives (microsilica) and quality aggregates, but the maturation time of the composite and its microstructure plays an important role.

Regulation the Properties of Materials on Magnesia Binder

2017 ◽  
Vol 265 ◽  
pp. 856-861
Author(s):  
V.V. Zimich
Keyword(s):  
Water Resistance ◽  
High Strength ◽  
Modifying Additives ◽  
Different Types ◽  
Properties Of Materials ◽  
Mineral Additives ◽  
Magnesia Material ◽  
Stone Density ◽  
By Products ◽  
Active Mineral Additives

Industrial waste pollution in the cities and the areas beyond them is a burning issue today. The only solution is recycling the by-products of primary production. Thus, the magnesia caustics are widely used in construction. However, their application is limited due to their high hygroscopicity. Many scientists were involved into the study of this problem justifying their achieved positive result by either using different types of sealers or introduction of fine composition active mineral additives into the binder. Moreover, all these studies mainly focused on the improvement of the water resistance of magnesia composites, while hygroscopic regulation was not significant. So it is important to study the process of environmental moisture accumulation in the pores of the magnesia material. When establishing the causes of the high hygroscopicity of magnesium materials, it was found that its value depends on environmental conditions (temperature, pressure and relative humidity); the specific surface area of magnesia stone; density of the sealer for magnesia binder; the chemical composition of various modifying additives and their influence on the properties of magnesia stone and materials based on it; the composition of the hydrated phases of magnesia stone with additives and without them; the presence of pores, their size and number in the structure of the stone; the surface charge of a magnesia stone. Studies have shown that high-strength water resistant chlorine magnesia stone in combination with modifying additives allows obtaining a composite material with hygroscopicity less than 2 %.

Influence of Different Types of Fine Aggregate on Cement Composites Resistance to High Temperatures

2014 ◽  
Vol 1000 ◽  
pp. 126-129 ◽  
Author(s):  
Tomáš Melichar ◽  
Jiří Bydžovský
Keyword(s):  
Mineralogical Composition ◽  
Mechanical Tests ◽  
Basic Material ◽  
Fine Aggregate ◽  
Cement Composites ◽  
Cement Mortars ◽  
Different Types ◽  
Natural Aggregates ◽  
The Impact

The paper discusses the impact of several selected aggregates on the basic material characteristics of cement composites. Both artificial and natural aggregates (four types in total) with different mineralogical composition were evaluated. The specimens were exposed to environments with the temperature up to 1000°C and then subjected to physico-mechanical tests. For the follow-up development of polymer-cement mortars, we selected two types of aggregates – fly ash aggloporite (FAA) and amphibolite (AMA).

scholarly journals POSSIBILITY OF USING VOLCANIC ROCKS IN THE CEMENT INDUSTRY

2019 ◽  
Author(s):  
В.А. Байтиев ◽  
Р.Г. Бисултанов ◽  
М.Ш. Саламанова ◽  
С-А. Ю. Муртазаев
Keyword(s):  
Strength Class ◽  
Volcanic Rocks ◽  
Cement Industry ◽  
Normal Density ◽  
High Quality ◽  
Volcanic Origin ◽  
Concrete Mixtures ◽  
Mineral Additives ◽  
Composite Cements ◽  
Active Mineral Additives

В данной статье раскрываются особенности формирования структуры цементных композиций с применением активной минеральной добавки вулканического происхождения. Полученные ре цептуры композиционных цементов позволят получать высококачественные бетоны с классом прочности от В60 до В100, снижать нормальную густоту бетонных смесей на 2530, при этом подвижность смеси остается постоянной. Кроме того, применение данной разработки позволит повышать темпы набора прочностных показателей бетона, что дает вероятность отказа от тепло вой обработки и способствует получению необходимой для распалубки прочности за промежуток времени 1824 часов. Работа выполнена в рамках исследований по реализации научного проекта 1848-200001 Высококачественные бетоны с повышенными эксплуатационными свойствами на основе местного природного и техногенного сырья , получившего поддержку Российского фонда фундаментальных исследований (РФФИ). The article reveals the features of the formation of the structure of cement compositions using active mineral additives of volcanic origin. The resulting composition of composite cements will make it possible to obtain high-quality concrete with a strength class from B60 to B100, reduce the normal density of concrete mixtures by 2530, while the mobility of the mixture remains constant. In addition, the use of this development will allow increasing the pace of a set of strength indicators of concrete, which gives the probability of refusal from heat treatment and helps to obtain the strength necessary for stripping for a period of 1824 hours.

scholarly journals STUDY OF SORPTIVITY OF SELF‐COMPACTING CONCRETE WITH MINERAL ADDITIVES

2006 ◽  
Vol 12 (3) ◽  
pp. 215-220 ◽  
Author(s):  
Luiz Antonio Pereira de Oliveira ◽  
João Paulo de Castro Gomes ◽  
Cristiana Nadir Gonilho Pereira
Keyword(s):  
Fly Ash ◽  
The Self ◽  
Capillary Absorption ◽  
Self Compacting Concrete ◽  
Normal Concrete ◽  
Hydraulic Lime ◽  
Concrete Mixtures ◽  
Slump Flow ◽  
Different Types ◽  
Mineral Additives

This work presents the results of a comparative study of the sorptivity, accomplished in mixtures of selfcompacting concrete with different types of additives and a normal concrete compacted by vibration. The self‐compacting concrete mixtures present slump‐flow of 650 ± 50 mm and have the same cement contents. In the self‐compacting mixtures, were used as additives, fly ash, silica fume, hydraulic lime and a mixture of fly ash and hydraulic lime. A modified carboxylates superplasticiser was used to obtain a specific workability. The capillary absorption was carried out at 7, 14 and 28 days of age, through a methodology described in the work. The results permit to conclude that the used additives propitiate the self‐compacting concrete. In terms of capillary absorption, the mixtures with fly ash have a better performance.

Study on the Process of Creating Fly Ash Body

2014 ◽  
Vol 1000 ◽  
pp. 166-169
Author(s):  
Vit Cerný ◽  
Šárka Keprdová
Keyword(s):  
Fly Ash ◽  
Building Materials ◽  
Experimental Testing ◽  
Ceramic Body ◽  
Mineralogical Composition ◽  
Different Types ◽  
External Sources ◽  
The Cost ◽  
The Impact

Production of artificial aggregate by clinkering process is currently relatively well-known way to efficiently use the potential of fly ash for building materials. Principle of clinkering can reduce the cost of natural gas and other potential external sources of heat through the use of own combustible substances. Course of firing and aggregate properties significantly depend on the type and character of the fly ash or fly ash mixture. Due to the high heterogeneity of these materials is relatively difficult to assess the impact of specific parameters (grain size, the content of Fe2O3, SiO2, CaO, amorphous phase, etc.). Due to the experimental testing of a large number of different types of fly ash and their mixtures, it will possible to verify at least some principles based on experience with the production of ceramic body. This article discusses the results of the sub-tests, dealt with influence of physico-mechanical properties, chemical and mineralogical composition of fly ash on the quality of the resulting ash body.

scholarly journals The Effect of the Composition of a Concrete Mixture on Its Volume Changes

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 828
Author(s):  
Martin Ťažký ◽  
Lenka Bodnárová ◽  
Lucia Ťažká ◽  
Rudolf Hela ◽  
Milan Meruňka ◽  
...  
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Specific Effect ◽  
Mineralogical Composition ◽  
Point Of View ◽  
Volume Changes ◽  
Granulated Blast Furnace Slag ◽  
Concrete Mixtures ◽  
The Individual ◽  
Mineral Additives

The presented research aims to clarify the specific effect of the individual components of concrete with Portland cement CEM I 42.5 R on the volume changes of concrete. The effect of the filler component was evaluated from the point of view of the composition and type of aggregate (crushed versus mined) and from the point of view of the mineralogical composition of the aggregate. Concrete formulas with a maximum aggregate grain size of 16 and 22 mm were assessed. The effect of the binder component on the shrinkage of the concrete was monitored on the concrete mixtures produced using the same aggregate and maintaining the same strength class of concrete, C 45/55. The effect of the addition of finely ground limestone, finely ground granulated blast furnace slag and coal high-temperature fly ash was monitored. It was found that the maximum aggregate grain and the type of grading curve do not have a significant effect on the volume changes of concrete. Concretes with mined aggregates showed lower shrinkage than concretes with crushed aggregates. The most significant is the effect of the type of aggregate on the volume changes in the first 24 h. Mineral additives have a positive effect on the elimination of the volume changes of concrete, while the addition of high-temperature fly ash proved to be the most suitable.

scholarly journals Effect of electrolytes with multicharged cations on the strength of stone made of a modified mixed air binder

2021 ◽  
Vol 2131 (4) ◽  
pp. 042091
Author(s):  
N N Shangina ◽  
T Y Safonova
Keyword(s):  
Compressive Strength ◽  
Aluminum Sulfate ◽  
High Strength ◽  
Hydrated Lime ◽  
X Ray ◽  
Calcium Hydrosilicates ◽  
Granulated Slag ◽  
Mineral Additives ◽  
Mixing Water ◽  
Active Mineral Additives

Abstract The possibility of obtaining mixed air binder of high strength and water resistance by using active mineral additives has been considered. In this work, the gypsum binder has been replaced by a combination of hydrated lime with active additives - metakaolin and granulated slag. The ratio effect of the silica component to the binder on the compressive strength of the stone was studied. According to the results of X-ray phase analysis, the presence of tobermorite-like calcium hydrosilicates and the absence of hydrate lime phase were diagnosed in the stone. The influence of electrolyte additives - salts with three-charged cations - on stone hardening kinetics is shown. Increase in the compressive strength of 28-day-old stone from the modified mixed air binder by 5% with the introduction of 1% of the binder mass aluminum sulfate in the mixing water was established. The use of FeCl3 solution for mixing the modified mixed air binder leads to a decrease in the compressive strength of the 28-day-old stone. The mixing of the modified mixed air binder with Al2(SO4)3 solution reduces the time of setting.

scholarly journals Investigating the Rheological Properties of Ultra High Strength Concrete Made with Various Superplasticizers

2019 ◽  
Vol 11 (2) ◽  
pp. 95-100
Author(s):  
Anthony Torres ◽  
Federico Aguayo ◽  
Srinivas Allena ◽  
Michael Ellis
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
Fine Particles ◽  
High Strength ◽  
Ductile Material ◽  
Strength Concrete ◽  
Lower Viscosity ◽  
Different Types ◽  
The Impact ◽  
Polycarboxylate Ether

Ultra-High Strength Concrete (UHSC) is a high-strength and highly ductile material formulated to provide compressive strengths exceeding 130MPa. UHSC materials typically have a very low water-to-cementitious ratio (w/cm), which requires the use of superplasticizers to disperse the fine particles and to make the material workable for placing, handling and consolidating. Common examples of superplasticizer compositions include Polynaphthalene Sulfonate (PNS), Polymelamine Sulfonate (PMS) and Polycarboxylate Ether (PCE) based polymers. This study focuses on assessing the impact of various superplasticizers on the compressive strength and rheological performance of a UHSC mixture. Four different types of superplasticizers were used; two different PCE based superplasticizers from a leading manufacturer, one PNS superplasticizer, and one PCE superplasticizer, both of which were provided by a local chemical provider. Specific properties assessed were the superplasticizers’ viscosity, concrete workability through the mortar-spread test, concrete rheology, and 7, 14, and 28 day compressive strengths. Two mixtures were produced with two w/cm (0.20 and 0.15), which would subsequently increase the amount of HRWRA needed, from 34.7L/m3 to 44.5L/m3. The results show that both name brand PCE superplasticizers produce a higher spread, lower viscosity, and a higher compressive strength at all ages tested up to 28 days than the two local superplasticizers. Additionally, the rheology test demonstrated that the name brand PCE superplasticizers, and UHSC produced with such superplasticizers, had a lower viscosity at all angular speeds than the local superplasticizers counterparts.

scholarly journals A multi-lab study of bilingual infants: Exploring the preference for infant-directed speech

2020 ◽  
Author(s):  
Krista Byers-Heinlein ◽  
Angeline Tsui ◽  
Christina Bergmann ◽  
Alexis K. Black ◽  
Anna Brown ◽  
...  
Keyword(s):  
North American ◽  
Large Scale ◽  
Native Language ◽  
American English ◽  
Age Groups ◽  
Linguistic Experience ◽  
Different Types ◽  
The Impact ◽  
Matched Samples ◽  
Two Age Groups

From the earliest months of life, infants prefer listening to and learn better from infant-directed speech (IDS) than adult-directed speech (ADS). Yet, IDS differs within communities, across languages, and across cultures, both in form and in prevalence. This large-scale, multi-site study used the diversity of bilingual infant experiences to explore the impact of different types of linguistic experience on infants’ IDS preference. As part of the multi-lab ManyBabies 1 project, we compared lab-matched samples of 333 bilingual and 385 monolingual infants’ preference for North-American English IDS (cf. ManyBabies Consortium, 2020 (ManyBabies 1)), tested in 17 labs in 7 countries. Those infants were tested in two age groups: 6–9 months (the younger sample) and 12–15 months (the older sample). We found that bilingual and monolingual infants both preferred IDS to ADS, and did not differ in terms of the overall magnitude of this preference. However, amongst bilingual infants who were acquiring North-American English (NAE) as a native language, greater exposure to NAE was associated with a stronger IDS preference, extending the previous finding from ManyBabies 1 that monolinguals learning NAE as a native language showed a stronger preference than infants unexposed to NAE. Together, our findings indicate that IDS preference likely makes a similar contribution to monolingual and bilingual development, and that infants are exquisitely sensitive to the nature and frequency of different types of language input in their early environments.

scholarly journals Clay as a Sustainable Binder for Concrete—A Review

2021 ◽  
Vol 1 (3) ◽  
pp. 134-168
Author(s):  
Seyed Sina Mousavi ◽  
Chandrasekhar Bhojaraju ◽  
Claudiane Ouellet-Plamondon
Keyword(s):  
Shape Stability ◽  
Treatment Methods ◽  
Experimental Database ◽  
Clay Particles ◽  
Concrete Mixtures ◽  
Different Types ◽  
Floc Strength ◽  
Hardened Properties ◽  
The Impact ◽  
Environmental Attack

The negative environmental impacts of Portland cement as a binder in the construction industry have created a growing impetus to develop sustainable alternative binders. Various types of clay have been considered as potential cement replacements. The impact of clays as cement replacement depends on the dosage and treatment methods. This paper presents a comprehensive review to determine the effects of different types of clay on the fresh and hardened properties of concrete mixtures by analyzing the experimental database reported by the literature, including raw, calcined, modified, nano, and organo. This study intends to show the process of optimizing the use of clay in concrete, the reason behind converting raw clay to modified types, and research gaps through a comparison study between different types of clays. The present review study shows that clay-based concrete mixtures have higher thixotropy and yield stress values, improving shape stability. This results in lower early-age shrinkage of the concrete. However, the high floc strength of clay-based concrete causes a reduction in flowability. Treatment methods of raw clay, such as calcination and nano-sized clay particles, improve concrete compressive strength. General results of the previous studies highlight that all types of clay investigated positively affect the resistance of concrete to environmental attack.

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