Behavior of Concrete Containing of Fine Recycled Aggregate

2016 ◽  
Vol 677 ◽  
pp. 260-265 ◽  
Author(s):  
Magdaléna Šefflová ◽  
Tereza Pavlů ◽  
Vladimír Hujer
Keyword(s):  
Czech Republic ◽  
Recycled Aggregate ◽  
Partial Replacement ◽  
Test Results ◽  
Natural Sand ◽  
The Czech Republic ◽  
Experimental Part ◽  
Concrete Mixtures ◽  
Crushed Concrete ◽  
Deformation Properties

The use of coarse recycled aggregate in concrete is already accepted in the Czech Republic but with specific restrictions. The problem is the use of fine recycled aggregate (FRA) in concrete. This paper is focused on behavior of concrete containing FRA. FRA, which originated from recycling plant in the Czech Republic, was used in an experimental part. FRA was obtained from demolished and crushed concrete structures. Four concrete mixtures were designed and prepared. The first concrete mixture was reference which did not include FRA. Natural sand was replaced by FRA in other concrete mixtures in varying ratio. There were tested physical, mechanical and deformation properties of concrete. According to test results it is possible to say that the use FRA as partial replacement of natural sand in concrete mixtures.

The Carbonation Depth of Fine Recycled Aggregate Concrete

2016 ◽  
Vol 722 ◽  
pp. 228-232 ◽  
Author(s):  
Magdaléna Šefflová ◽  
Tereza Pavlů
Keyword(s):  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Partial Replacement ◽  
Concrete Durability ◽  
Test Results ◽  
Carbonation Depth ◽  
Natural Sand ◽  
Conventional Concrete ◽  
Concrete Mixtures ◽  
Carbonation Resistance

This paper is focused on carbonation resistance of fine recycled aggregate (FRA) concrete. Durability of FRA concrete is connected with uncertainties and doubts. One of the most unknown aspects of FRA cocnrete is carbonation resistance. This paper presents results of carbonation depth of FRA concrete. The FRA was originated from crushed construction and demolition (C&D) waste. There were prepared a total four concrete mixture. The first mixture was reference, did not include the FRA. In other concrete mixtures, natural sand was replaced by the FRA in various replacement ratios, specifically 10%, 20% and 30%. All prepared concrete mixtures were designated with the same parameters for clear comparison. From the test results it is possible to say that the use of the FRA as partial replacement of natural sand in concrete influences carbonation resistance of concrete. The carbonation depth was higher for concrete samples with the use of FRA. However it is possible to say that according to the carbonation resistance, the FRA concrete is possible to be used in the same applications as conventional concrete but it is necessary to verify this results.

The Behavior of FRA Concrete with High Replacement Ratio

2018 ◽  
Vol 760 ◽  
pp. 204-209 ◽  
Author(s):  
Magdaléna Šefflová
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Absorption Capacity ◽  
Recycled Aggregate ◽  
Partial Replacement ◽  
Hardened Concrete ◽  
Replacement Ratio ◽  
Natural Sand ◽  
Concrete Mixtures

This study deals with determination of the properties of the fine recycled aggregate (FRA) concrete with partial replacement of natural sand in concrete mixtures. The FRA was obtained from concrete waste and crushed on fraction 0 – 4 mm by laboratory jaw crusher. The geometrical and physical properties of natural sand and the FRA were tested. The main goal of this study is evaluation of the basic physical and mechanical properties of the concrete with partial natural sand replacement by the FRA such as workability, water absorption capacity, compressive strength and flexural strength. A total four concrete mixtures were prepared. The first concrete mixture was prepared only with natural sand, did not include the FRA. In other concrete mixtures, natural sand was replaced by the FRA in various replacement ratios (40 %, 50 %, and 60 %). All concrete mixtures were designated with the same parameters for clear comparison. The workability of fresh concrete mixtures and physical and mechanical properties of hardened concrete were tested.

Influence of Recycled Aggregate Quality on Recycled Concrete

2015 ◽  
Vol 1106 ◽  
pp. 45-48 ◽  
Author(s):  
Magdaléna Šefflová ◽  
Tereza Pavlů
Keyword(s):  
Negative Influence ◽  
Recycled Concrete ◽  
The Other ◽  
Recycled Aggregate ◽  
Test Results ◽  
The Czech Republic ◽  
Natural Aggregate ◽  
Concrete Mixtures ◽  
Reference Mixture

This article deals with the influence of recycled aggregate quality on recycled concrete. Replacement of natural aggregate by recycling aggregate has a negative influence on the properties of concrete. Three types of recycled aggregate were used for the production of concrete. The samples of recycled aggregate were obtained from two recycling plants in the Czech Republic. The samples of recycled aggregate were tested by pycnometric method. From the test results, a different quality of recycled aggregate was discovered. For the testing of concrete, a total of eight concrete mixtures were made, one of which was a reference mixture and the natural aggregate was replaced by recycled aggregate of varying ratio in the other mixtures. Finally, it is possible to say that use of recycled aggregate in concrete influences the properties of concrete. This influence depends on the quality and amount of recycled aggregate in the concrete.

Study of the Mechanical Properties Development of Concrete Containing Fine Recycled Aggregate

2016 ◽  
Vol 827 ◽  
pp. 267-270 ◽  
Author(s):  
Magdaléna Šefflová ◽  
Tereza Pavlů
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Czech Republic ◽  
Recycled Aggregate ◽  
Future Research ◽  
Building Structures ◽  
Replacement Ratio ◽  
The Czech Republic ◽  
Concrete Mixtures ◽  
Concrete Properties

This paper is focused on the mechanical properties development of fine recycled aggregate (FRA) concrete. FRA was obtained from recycling plant in the Czech Republic. There were prepared four concrete mixtures in the laboratory. The first mixture was reference (REF) with fine natural aggregate (FNA). FNA was replaced in concrete mixtures R10, R20 and R30 in varying replacement ratio. The concrete mixtures R10, R20 and R30 contained 10 %, 20 % and 30 % FRA. There were tested properties of concrete. Finally, it is possible to say that the use of the FRA in concrete influences concrete properties. It is necessary to verify of probably an improvement of compressive strength of FRA concrete in future research. However, FRA concrete is possible to be used in the manufacturing of building structures, but it is necessary to test durability and lifespan of FRA concrete.

The Properties of Fine Recycled Aggregate Concrete Containing Recycled Bricks from Construction and Demolition Waste

2018 ◽  
Vol 760 ◽  
pp. 193-198 ◽  
Author(s):  
Kristina Fořtová ◽  
Tereza Pavlů
Keyword(s):  
Recycled Aggregate Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Natural Sand ◽  
Aggregate Concrete ◽  
Freeze Thaw ◽  
Recycled Fine Aggregate

This paper presents research results of recycled fine aggregate concrete testing. The main aim of this contribution is verification of properties of fine aggregate concrete with partial replacement of fine natural aggregate by recycled masonry aggregate originated from construction and demolition waste. The influence of partial replacement of natural sand to mechanical properties and freeze-thaw resistance is described. The compressive strength and flexural strength were tested at the age of 28 and 60 days and after 25, 50, 75 and 100 freeze-thaw cycles. Partial replacement of natural sand was 0, 25 and 50 % for all these tests. Prismatic specimens were examined.

Waste Building Materials to Roads in Czech Republic

2016 ◽  
Vol 832 ◽  
pp. 10-17
Author(s):  
Dušan Stehlík ◽  
Petr Hyzl ◽  
Michal Varaus
Keyword(s):  
Sustainable Development ◽  
Czech Republic ◽  
Building Material ◽  
Building Materials ◽  
Recycled Aggregate ◽  
Research Projects ◽  
Research Focus ◽  
The Czech Republic ◽  
Granular Mixtures

Using waste building materials in pavements is one of the goals of transportation sustainable development in the Czech Republic. As part of research projects of the Technology Agency of the Czech Republic, a project was devised, which focused on maximal utilization of waste building materials when constructing pavements. After the initial verification of properties of the recycled aggregate (especially concrete waste building material), the research focus shifted towards the utilization of these waste building materials in cement bound granular mixtures.

scholarly journals Mechanical and Durability Properties of Concrete Made with Used Foundry Sand as Fine Aggregate

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
G. Ganesh Prabhu ◽  
Jin Wook Bang ◽  
Byung Jae Lee ◽  
Jung Hwan Hyun ◽  
Yun Yong Kim
Keyword(s):  
Substitution Rate ◽  
International Standards ◽  
Fine Aggregate ◽  
Test Results ◽  
Natural Sand ◽  
Foundry Sand ◽  
Durability Properties ◽  
Concrete Mixtures ◽  
Concrete Production ◽  
Strength And Durability

In recent years, the construction industry has been faced with a decline in the availability of natural sand due to the growth of the industry. On the other hand, the metal casting industries are being forced to find ways to safely dispose of waste foundry sand (FS). With the aim of resolving both of these issues, an investigation was carried out on the reuse of waste FS as an alternative material to natural sand in concrete production, satisfied with relevant international standards. The physical and chemical properties of the FS were addressed. The influence of FS on the behaviour of concrete was evaluated through strength and durability properties. The test results revealed that compared to the concrete mixtures with a substitution rate of 30%, the control mixture had a strength value that was only 6.3% higher, and this enhancement is not particularly high. In a similar manner, the durability properties of the concrete mixtures containing FS up to 30% were relatively close to those of control mixture. From the test results, it is suggested that FS with a substitution rate of up to 30% can be effectively used in concrete production without affecting the strength and durability properties of the concrete.

Options of UHPC in the Czech Republic

2016 ◽  
Vol 722 ◽  
pp. 292-297
Author(s):  
Klára Křížová ◽  
Rudolf Hela
Keyword(s):  
Czech Republic ◽  
Bending Strength ◽  
Essential Element ◽  
Fundamental Characteristic ◽  
The Czech Republic ◽  
Experimental Part ◽  
Concrete Production

This contribution describes the possibilities of UHPC concrete production. To begin with, the fundamental characteristic of this concrete, its development and composition are provided. An essential element for achieving the extraordinary properties of UHPC concrete is its composition. The experimental part describes the UHPC design, test examples and the testing of certain compressive strengths and tensile bending strength after 1 and 28 days. Simultaneously, basic UHPC buildings in the Czech Republic are mentioned.

Study on Properties of Self-Compacting Concrete Prepared with Coarse Recycled Concrete Aggregate

2014 ◽  
Vol 638-640 ◽  
pp. 1494-1498 ◽  
Author(s):  
Jian Jie Yu ◽  
Jian Gong ◽  
Jie Ming Zou ◽  
Wei Kang Yang
Keyword(s):  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Working Environment ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Self Compacting Concrete ◽  
Recycled Coarse Aggregate ◽  
Concrete Mixtures ◽  
Crushed Concrete ◽  
Construction Efficiency

Self-compacting concrete is absent of vibration noise during casting, improves the construction efficiency, and provides a healthier working environment compared to the traditional vibrated concrete. The potential coarse recycled aggregate obtained from crushed concrete for making self-compacting concrete was considered to replace the aggregate with the percentage of substitution of recycled coarse aggregate 0%, 50% and 100%. Thus, three types of concrete mixtures were made. Experiments show that, the properties of these concrete only have slight differences and recycled coarse aggregate can be successfully used for the preparation of self-compacting concrete. The method solves the problem of the waste disposal by the demolition of old buildings.

Influence of Mix Proportions on Water Absorption of RCA Concretes

2016 ◽  
Vol 722 ◽  
pp. 187-194
Author(s):  
Roman Jaskulski ◽  
Paweł Las ◽  
Wojciech Kubissa
Keyword(s):  
Water Absorption ◽  
Probabilistic Models ◽  
Recycled Aggregate ◽  
Test Results ◽  
Mean Values ◽  
Concrete Mixtures ◽  
The Subject ◽  
The Mean ◽  
Best Fit ◽  
Good Agreement

The subject of the work is to develop probabilistic models defining the water absorption of concretes made ​​with the use of recycled aggregate (RCA). For the study 16 series of concrete mixtures were made with a 50 mass% share of recycled aggregate in the whole amount of coarse aggregate. The analysis of test results aimed at formulating a relationship between water absorption value and selected parameters of the composition of concretes. The objective was to find a model giving the best fit between calculated values and test results. Formulated models were then used in probabilistic modeling absorption using a Monte Carlo simulation. The results indicate a good agreement of the mean values of water absorption and possibility of good fitting of the standard deviation if an additional summand is introduced into the model.

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