scholarly journals DEVELOPMENT OF COMPOSITIONS OF FILLED INSULATORS BASED ON SECONDARY RAW FOR MONOLITHIC HIGH-STRENGTH CONCRETE

2019 ◽  
Vol 46 (3) ◽  
pp. 129-138
Author(s):  
A. Kh. Alaskhanov ◽  
T. S. Murtazaeva ◽  
M. S.-A. Saidumov ◽  
A. O. Omarov
Keyword(s):  
Structure Formation ◽  
High Strength Concrete ◽  
Raw Materials ◽  
High Strength ◽  
Recycled Materials ◽  
Strength Concrete ◽  
Regulatory Documents ◽  
Concrete Mixtures ◽  
Technogenic Raw Materials ◽  
Mineral Fillers

Objectives Development of compositions filled with binders based on recycled materials for monolithic high-strength concrete.Method The research methods adopted in the work are based on the theoretical principles and laws of designing and optimizing polydisperse multicomponent systems, the phase and structure formation of clinker minerals, the logic of mathematical calculations, the technological features of the structure formation of composite masses, the theoretical principles of controlling the rheological processes of mixes. All experimental data presented in the work were obtained according to the methods of current regulatory documents (GOST, recommendations, etc.).Result The paper provides an analysis of the experience of using recycled materials in the form of products of demolition of buildings and structures, the technology for producing secondary raw materials for concrete on their basis. Formulations filled with binders with an activity of 60-71 MPa with finely dispersed mineral fillers from concrete scrap and brick combat with a ratio of 70:30%, respectively, were developed and investigated.Conclusion The optimal formulations of highly mobile concrete mixtures were designed using local natural and technogenic raw materials with a grade of P5 cone sediment and persistence for more than 8 hours to obtain high-strength classes of compressive strength up to B60-B80 with unique operational properties. 

scholarly journals FINE-GRAINED HIGH-STRENGTH CONCRETE

2020 ◽  
Vol 3 (1) ◽  
pp. 39-43 ◽  
Author(s):  
A. Tolstoy
Keyword(s):  
Structure Formation ◽  
Mineral Composition ◽  
Production Technology ◽  
High Strength Concrete ◽  
Raw Materials ◽  
Stable State ◽  
High Strength ◽  
Economic Feasibility ◽  
Strength Concrete ◽  
Fine Grained

the article discusses the possibilities of improving the strength characteristics of fine-grained concrete. Modification of compositions and production technology of fine-grained high-strength concrete is possible with the use of natural and man-made raw materials of various chemical and mineral composition. It is shown that it is possible to increase the economic feasibility of high-strength fine-grained concretes with the preservation of performance characteristics due to the use of man-made raw materials and production waste. The issues of controlling the processes of structure formation and identifying a potentially stable state of hardening compositions are considered, possibly on the basis of modification and design methods for the composition of construction objects with improved properties.

Properties of High Strength Concrete with Calcined Diatomaceous Earth as Cement Replacement under Compression

2020 ◽  
Vol 402 ◽  
pp. 7-13
Author(s):  
Muttaqin Hasan ◽  
Aris Muyasir ◽  
Taufiq Saidi ◽  
Husaini ◽  
Raudha Azzahra
Keyword(s):  
Compressive Strength ◽  
Modulus Of Elasticity ◽  
High Strength Concrete ◽  
Diatomaceous Earth ◽  
High Strength ◽  
Compression Load ◽  
Strength Concrete ◽  
Cement Replacement ◽  
Concrete Mixtures ◽  
Compressive Strength Of Concrete

In this research, calcined diatomaceous earth from Aceh Besar, Indonesia was used as cement replacement in producing high strength concrete. Four concrete mixtures in which the percentage of cement replacement of 0%, 5%, 10% and 15% by weight were studied. Four cylinder-specimens with 100 mm diameter and 200 mm high were prepared for each mixture. The compression load was applied on the specimens at the age of 28 days until the specimens failed. The mixture without calcined diatomaceous earth was more workable than that with diatomaceous earth. The compressive strength of concrete with diatomaceous earth in this study was almost the same for all mixture. However, those compressive strength was lower than the compressive strength of concrete without calcined diatomaceous earth for about 14.6%. Modulus of elasticity of high strength concrete decreased with increasing of cement replacement percentage.

scholarly journals Life-Cycle Assessment of High-Strength Concrete Mixtures with Copper Slag as Sand Replacement

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Aysegul Petek Gursel ◽  
Claudia Ostertag
Keyword(s):  
Life Cycle ◽  
Environmental Impacts ◽  
High Strength Concrete ◽  
High Strength ◽  
Copper Slag ◽  
Embodied Energy ◽  
Fine Aggregate ◽  
Natural Sand ◽  
Strength Concrete ◽  
Concrete Mixtures

Aggregate consumption rates have now exceeded natural renewal rates, signaling shortages both locally and globally. Even more concerning is that the worldwide markets for construction aggregates are projected to grow at an annual rate of 5.2% in the near future. This increase is attributed to rapid population growth coupled with the economic development worldwide. In terms of material availability, one of the most vulnerable regions is the Asia-Pacific region specifically, Singapore, where there is higher demand but limited availability of natural sand and gravel for use as aggregates in concrete construction projects. This paper focuses mainly on the environmental impacts of fine aggregate alternatives used in high-strength concrete applications in Singapore, which is one of the major global importers of natural sand following China. Singapore has been experiencing political and environmental challenges linked to the shortage of natural sand use as aggregates, even while the demand is increasing in the construction sector. Copper slag, a readily available waste material from shipyards in Singapore, is a possible replacement material for a portion of the natural sand in concrete mixtures, thus sustaining the projected growth in the region. A life-cycle assessment approach is applied to investigate the environmental impacts of copper slag and its alternative use as natural sand in high-strength concrete applications in Singapore. The system boundary consists of the major production processes of concrete constituents (including Portland cement and fine and coarse aggregates, with CS considered as fine aggregate) from a cradle-to-gate perspective, consisting of relevant life-cycle phases of raw materials extraction, transportation, and production processes at the relevant facility where the production occurs. Output from the assessment is provided in terms of embodied energy use and air emissions of concrete mixes with varying percentages of copper slag as fine aggregate. Results show that environmental impacts of aggregates decrease with the increasing substitution rate of natural sand with copper slag when calculated on the basis per unit volume of the concrete mix. For example, 40% and 100% sand replacements with copper slag result in a reduction of 8% and 40% in embodied energy, 12% and 30% in global warming potential, 8% and 41% in acidification, and 7% and 35% in particulate matter formation, respectively. Normalized impacts (i.e., normalized with respect to compressive strength) are observed to remain at almost similar levels for concrete mixes with up to 40% natural sand having been replaced with copper slag. Therefore, it is recommended that replacement of fine aggregates by 40–50% of copper slag (by weight) will produce concrete mixtures with comparable environmental impacts while maintaining feasible durability and strength properties.

scholarly journals Production of Greener High-Strength Concrete Using Russian Quartz Sandstone Mine Waste Aggregates

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5575
Author(s):  
Aleksandr Tolstoy ◽  
Valery Lesovik ◽  
Roman Fediuk ◽  
Mugahed Amran ◽  
Murali Gunasekaran ◽  
...  
Keyword(s):  
High Strength Concrete ◽  
Raw Materials ◽  
Mine Waste ◽  
Natural Radionuclides ◽  
High Strength ◽  
Morphological Properties ◽  
Cement Matrix ◽  
Natural Activity ◽  
Strength Concrete ◽  
The Cost

Quartz sandstone (QS) is a mine waste; therefore, its use in construction allows for both reducing the cost of the concrete and contributing to the utilization of waste. The scientific originality of this study is the identification of models of the effect of QS aggregate on the physicomechanical, durability characteristics, and eco-safety of greener high-strength concrete. The study used an energy-efficient method of non-thermal effects of electromagnetic pulses on the destruction mechanisms of quartz-containing raw materials. The characteristics of quartzite sandstone aggregates, including the natural activity of radionuclides, were comprehensively studied. The features of concrete hardening, including the formation of an interfacial transition zone between the aggregate and the cement matrix, were studied, taking into account the chemical and morphological features of quartzite sandstone. In addition, the microstructural and morphological properties of concrete were determined after a 28 day curing. In this study, the behaviors of the concrete with QS aggregate were investigated, bearing in mind the provisions of geomimetics science on the affinity of structures. The results obtained showed that the QS aggregate had the activity of natural radionuclides 3–4 times lower compared to traditional aggregates. Efficient greener concrete with a 46.3 MPa compressive strength, water permeability grade W14, and freeze–thaw resistance of 300 cycles were also obtained, demonstrating that the performance of this greener concrete was comparable to that of traditional concrete with more expensive granite or gabbro diabase aggregates.

scholarly journals Tensile Properties of Very-High-Strength Concrete for Penetration-Resistant Structures

1999 ◽  
Vol 6 (5-6) ◽  
pp. 237-245 ◽  
Author(s):  
E.F. O’Neil ◽  
B.D. Neeley ◽  
J.D. Cargile
Keyword(s):  
Tensile Properties ◽  
High Strength Concrete ◽  
High Strength ◽  
Conventional Concrete ◽  
Strength Concrete ◽  
New Family ◽  
Concrete Mixtures ◽  
Study Results ◽  
Protective Structures ◽  
Very High

This paper describes the potential suitability of a new family of concrete mixtures for use in protective structures. Two very-high-strength concrete mixtures are discussed and experimental results of penetration studies on one of these are presented. The results are compared to penetration-study results of other, more conventional concrete mixtures, and the advantages of the very-high-strength mixtures are described.

scholarly journals The Use of Fly Ash as Additive Material to High Strength Concrete

2018 ◽  
Vol 20 (2) ◽  
pp. 65-70
Author(s):  
Endah Kanti Pangestuti ◽  
Sri Handayani ◽  
Mego Purnomo ◽  
Desi Christine Silitonga ◽  
M. Hilmy Fathoni
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Strength Concrete ◽  
Building Materials ◽  
High Strength ◽  
Coal Waste ◽  
Normal Concrete ◽  
Strength Concrete ◽  
Concrete Mixtures ◽  
Compressive Strength Of Concrete

Abstract. The use of coal waste (Fly Ash) is currently being developed in building materials technology, as a high-strength concrete mix material. This study aims to determine the strength of concrete by adding fly ash as a substitute for cement in high-strength concrete mixtures. This research was conducted with an experimental method to obtain results and data that would confirm the variables studied. The total number of specimens used in this study were 36 pieces with different sizes of cube tests which were 15 cm x 15 cm x 15 cm. A total of 36 concrete samples were used to test the compressive strength of concrete with a percentage of Fly Ash in  0% (normal concrete), 20%, 25% and 30% with a concrete treatment age of 7 days, 21 days and 28 days. A total of 12 more samples were used to test water absorption in concrete at 28 days of maintenance. Each percentage percentage of Fly Ash uses 3 concrete test samples. The increase in compressive strength occurs at 7, 21 and 28 days in concrete. However, the compressive strength of concrete produced by concrete using the percentage of Fly Ash is always lower than the value of normal concrete compressive strength. From testing the compressive strength of concrete at 28 days of treatment with content of 0%, 20%, 25% and 30% Fly Ash obtained results of 45.87 MPa, 42.67 MPa, 40.89 MPa, and 35.27 MPa respectively

scholarly journals Effect of Using River Sand on The Strength of Normal and High Strength Concrete

2018 ◽  
Vol 7 (4.20) ◽  
pp. 222 ◽  
Author(s):  
Haitham Al-Thairy
Keyword(s):  
High Strength Concrete ◽  
High Strength ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
River Sand ◽  
Strength Concrete ◽  
Concrete Mixtures ◽  
Test Parameters ◽  
Normal Strength ◽  
Compressive And Flexural Strengths

The shortage and high cost of quarries sand in some regions around the world has motivated engineers and researchers to investigate the possibility and feasibility of using other materials to be used as a fine aggregate in concrete mixtures. The main objective of this research is to experimentally investigate the effect of using river sand as a partial replacement of the ordinary quarries sand on the mechanical properties of normal and high strength concrete. Nine concrete mixtures were prepared and tested in terms of fresh and hardened properties using different replacement ratios of the required proportion of the normal sand. Four replacement ratios were used for normal strength concrete (NSC) which are: 0%, 25%, 50% and 75%, whereas, five replacement ratios were used for high strength concrete (HSC) namely: 0%, 35%, 60% and 90%. For each strength grade, the test parameters of the prepared mixtures included compressive and tensile strength. The experimental test results have revealed that it is possible to obtain a normal and high strength concrete with acceptable compressive and flexural strengths values by using river sand with replacement ratios up to 25% and 35% for NSC and HSC, respectively. When the replacement ratios were increased to more than the aforementioned ratios, the strength of the concrete decreased accordingly.  

A NEW KIND OF CEMENT AS A SOLUTION TO THE ENVIRONMENTAL CHALLENGES OF MODERNITY

2021 ◽  
Author(s):  
G Kasimova
Keyword(s):  
Fly Ash ◽  
High Strength Concrete ◽  
Fresh Concrete ◽  
Raw Materials ◽  
Road Construction ◽  
High Strength ◽  
Strength Concrete ◽  
Cement Replacement ◽  
Air Content ◽  
Concrete Mix

The article presents studies on the production of high-strength concrete for road construction for a given 28-day strength on local raw materials. As a cement-replacement additive, fly ash was used. It was found out that the fresh concrete mixture had adequate workability, the air content of the concrete mix withthe sperplastifizer, the 28-day strength of the base mixture, which corresponded to the required strength.

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