scholarly journals Stavební odpad jako náhrada jemné frakce v betonech – hodnocení fytotoxicity vůči okřehku

Entecho ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 10-14
Author(s):  
Hedvika Roztočilová ◽  
Diana Mariaková ◽  
Klára Anna Mocová
Keyword(s):  
Construction Industry ◽  
Renewable Resources ◽  
Mineral Resources ◽  
Aquatic Organisms ◽  
Inhibitory Effect ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Brick Powder ◽  
Ecotoxicity Tests ◽  
Primary Materials

Stavebnictví patří mezi největší odběratele nerostných surovin, s čímž souvisí i následná produkce odpadů. Výroba nejvíce využívaných produktů v tomto odvětví, jako jsou například cihly a betony, je v současné době závislá na neustálé těžbě primárních materiálů z neobnovitelných zdrojů. Značný potenciál pro ušetření primárních zdrojů má ve stavebnictví opětovné využívání recyklátů. Pro využití odpadních materiálů jako náhrady určité složky betonu je důležité, aby byly zachovány jeho mechanické a chemické vlastnosti. Současně je na místě posoudit také míru dopadu na životní prostředí. Jednou z možností je provést výluhové zkoušky a následné testy ekotoxicity s vodními organismy. Cílem této práce bylo posoudit a porovnat fytotoxické účinky výluhů cihelného prachu, tří druhů písků z betonových recyklátů a referenčního materiálu (přírodního písku). Hodnocen byl růst biomasy a množství chlorofylu. Výsledky ukázaly velké rozdíly mezi vzorky. Písek nepůsobil toxicky, účinky výluhu cihelného prachu se téměř nelišily od kontroly. Beton, který byl již jednou ecyklován, působil mírně inhibičně, zatímco výluhy podlahového betonu s obsahem epoxidového lepidla a betonu pocházejícího z dálnice měly výrazné toxické až letální účinky. Abstract (EN) Construction sector is one of the largest consumers of mineral resources, which is also related to the subsequent production of waste. The production of the most widely used products in this sector, such as bricks and concrete, is currently dependent on the constant extraction of primary materials from non-renewable resources. The reuse of recycled materials in the construction industry has considerable potential for saving of the primary resources. For the use of waste materials as a substitute for a certain component of concrete, it is important that its mechanical and chemical features remain unchanged. At the same time, it is appropriate to assess the degree of impact on the environment. One option is to perform leaching tests and subsequent ecotoxicity tests with aquatic organisms. The aim of this study was to determine and compare the phytotoxic effects of brick powder extracts, three types of recycled concrete aggregate and reference material (natural aggregate). Biomass growth and chlorophyll levels were evaluated. The results showed large differences among the samples. The sand was not toxic, the effect of brick dust was almost the same as the control. Concrete, which has already been recycled once, had a slightly inhibitory effect, while extracts of floor concrete containing epoxy glue and concrete from the highway had significant toxic to lethal effects.

SCC Produced with Recycled Concrete Aggregates

2012 ◽  
Vol 512-515 ◽  
pp. 2986-2989 ◽  
Author(s):  
Yuan Yong ◽  
Ueda Takao ◽  
Chun Long Yu
Keyword(s):  
Construction Industry ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Noise Emission ◽  
Self Compacting Concrete ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Complicated Process ◽  
Traditional Construction

The major content in concrete is aggregates. Reduce its usage and replaced with recycled concrete aggregate (RCA) could not only mitigate consuming of natural resources but avoid the treatment of solid wastes. Furthermore, producing self-compacting concrete (SCC) with RCA is a way for traditional construction industry in saving energy and avoiding noise emission. To seek the proper way in preparation of SCC with RCA, preparation of RCA, composition design, microstructure evolution with hydration, and mechanical properties are investigated within this study. It is found that successful producing of SCC with RCA is not a complicated process.

scholarly journals USE OF RECYCLED CONCRETE AGGREGATE IN CONCRETE: A REVIEW

2013 ◽  
Vol 19 (6) ◽  
pp. 796-810 ◽  
Author(s):  
Md. Safiuddin ◽  
Ubagaram Johnson Alengaram ◽  
Md. Moshiur Rahman ◽  
Md. Abdus Salam ◽  
Mohd. Zamin Jumaat
Keyword(s):  
Construction Industry ◽  
Chemical Properties ◽  
Recycled Concrete ◽  
Future Research ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Hardened Properties ◽  
Negative Environmental Impact ◽  
Published Research ◽  
And Chemical Properties

The use of recycled concrete aggregate (RCA) in concrete as partial and full replacements of natural coarse aggregate is growing interest in the construction industry, as it reduces the demand for virgin aggregate. In addition, the use of RCA leads to a possible solution to the environmental problem caused by concrete waste and reduces the negative environmental impact of the aggregate extraction from natural resources. This paper presents a comprehensive review on the use of RCA in concrete based on the experimental data available in the published research. The most important physical, mechanical, and chemical properties of RCA are discussed in this paper. However, more emphasis has been given to discuss the effects of RCA on the fresh and hardened properties and durability of concrete. This paper also identifies the gaps existing in the present state of knowledge on RCA and RCA concrete and provides some recommendations for future research.

scholarly journals Sustainability of concrete using recycled aggregate: a review

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Mohammad Umar Khan ◽  
Manju Dominic
Keyword(s):  
Construction Industry ◽  
Well Being ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Virgin Material ◽  
Recycled Concrete Aggregate ◽  
Development Environment ◽  
The World ◽  
Construction Activity

Sustainable development is essential to the well-being of our planet, human development, and the continued growth of society. As we know, concrete are the most commonly used substance in the world, after water. However, recycled concrete is the biggest advantage for us. Nowadays the construction industry also tries to replace the virgin material to reduce the environmental impact, global warming, pollution, etc. The construction activity and old structural building also is an issue for the environment. The reuse and recycle of concrete would therefore also reduce the burden on the environment. So this paper will give a summary of recycled concrete aggregate, their sustain on the environment, properties of the application of recycled aggregate, and the resultant of their properties of recycled concrete aggregate. Keywords- Aggregate, Concrete, Construction Development, Environment, Recycled, Sustainable.

scholarly journals Physical, Deformation, and Stiffness Properties of Recycled Concrete Aggregate

2021 ◽  
Vol 13 (8) ◽  
pp. 4245
Author(s):  
Katarzyna Gabryś ◽  
Emil Soból ◽  
Wojciech Sas
Keyword(s):  
Recycled Concrete ◽  
Experimental Program ◽  
Concrete Aggregate ◽  
Test Results ◽  
Recycled Concrete Aggregate ◽  
Granulometric Analysis ◽  
Stiffness Properties ◽  
Grain Distribution ◽  
Natural Aggregates ◽  
Critical Reduction

The construction sector is currently struggling with the reuse of waste originating from the demolition and modernization of buildings and roads. Furthermore, old buildings are gradually being replaced by new structures. This brings a significant increase of concrete debris to waste landfills. To prevent this, many studies on the possibilities of recycling concrete, known as recycled concrete aggregate (RCA), have been done. To broaden the applicability of reused concrete, an understanding of its properties and engineering behavior is required. A difficulty in sustainable, proper management of RCA is the shortage of appropriate test results necessary to assess its utility. For this reason, in the present study, the physical, deformation, and stiffness properties of RCA with gravely grain distribution were analyzed carefully in the geotechnical laboratory. To examine the mentioned properties, an extensive experimental program was planned, which included the following studies: granulometric analysis, Proctor and oedometer tests, as well as resonant column tests. The obtained research results show that RCA has lower values of deformation and stiffness parameters than natural aggregates. However, after applying in oedometer apparatus repetitive cycles of loading/unloading/reloading, some significant improvement in the values of the parameters studied was noticed, most likely due to susceptibility to static compaction. Moreover, some critical reduction in the range of linear response of RCA to dynamic loading was observed.

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