scholarly journals Influence of Recycled Aggregates on the Mechanical Properties of Synthetic Fibers-Reinforced Masonry Mortars

2021 ◽  
Vol 6 (6) ◽  
pp. 84
Author(s):  
Alberto Morón ◽  
Daniel Ferrández ◽  
Pablo Saiz ◽  
Gabriela Vega ◽  
Carlos Morón
Keyword(s):  
Raw Materials ◽  
Polypropylene Fiber ◽  
High Volume ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Construction Sector ◽  
The European Union ◽  
Synthetic Fibers ◽  
Reinforced Masonry ◽  
Concrete Recycling

The construction sector is one of the main consumers of raw materials and generates a high volume of waste within the European Union. The search for new materials that are more sustainable and respectful of the environment has become a challenge for countries with a high degree of industrialization. In this work, a study of the most relevant properties of masonry mortars made with recycled aggregates and reinforced with synthetic fibers was carried out. Three types of aggregates were used—natural, concrete recycling and ceramic recycling—and two types of reinforcing fibers: polypropylene and polyolefin. In this way, various tests of physical-mechanical characterization and a statistical analysis of the results were carried out. It has been shown that the mortars made from aggregate recycled concrete and reinforced with polypropylene fiber are the ones with the best properties for application in the construction sector, although without improving the properties of traditional mortars made from natural aggregate and without fibers.

scholarly journals Comparative study of the influence of three types of fibre in the shrinkage of recycled mortar

2018 ◽  
Vol 68 (332) ◽  
pp. 168 ◽  
Author(s):  
P. Saiz-Martínez ◽  
D. Ferrández-Vega ◽  
C. Morón-Fernández ◽  
A. Payán de Tejada-Alonso
Keyword(s):  
Negative Impact ◽  
Polypropylene Fiber ◽  
Capacitive Sensor ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Moisture Loss ◽  
Recycled Aggregates ◽  
Fiber Types ◽  
Demolition Waste ◽  
Recycled Concrete Aggregates

Construction and demolition waste can be used as a substitution of natural aggregate in mortar and concrete elaboration. A poorer quality of recycled aggregates generally has negative impact on mortar properties. Shrinkage is one of the properties that experiences worse outcome due to the higher absorption of recycled aggregates. This research evaluates the potential shrinkage of mortars elaborated with recycled concrete aggregates both with and without fibres addition, as well as the relation between moisture loss and shrinkage caused by mortar drying process using a capacitive sensor of the authors’ own design. Two different mortar dosages 1:3 and 1:4 and three fiber types: polypropylene fiber, fiberglass and steel fiber, in different proportions were used. Obtained results show that the use of polypropylene fiber improves the recycled mortars performance against shrinkage in 0.2%. Moreover, a clear relation between dry shrinkage and moisture loss was observed.

Relationship between the Compressive and Tensile Strength of Recycled Concrete

2011 ◽  
Vol 324 ◽  
pp. 348-351 ◽  
Author(s):  
Rouba El Dalati ◽  
Pierre Matar ◽  
Sara Haddad ◽  
Fadi Hage Chehade
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Limited Range ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Concrete Compressive Strength ◽  
Concrete Recycling ◽  
The Relationship ◽  
Special Composition

Concrete recycling consists of crushing the concrete provided by demolishing the old constructions, and of using the resulted small pieces as aggregates in the new concrete compositions. The resulted aggregates are called recycled aggregates and the new mix of concrete containing a percentage of recycled aggregates is called recycled concrete. Our previous researches have indicated the optimal percentages of recycled aggregates to be used for different cases of recycled concrete related to the original aggregates nature. All results have shown that the concrete compressive strength is significantly reduced when using recycled aggregates. In order to obtain realistic values of compressive strength, some tests have been carried out by adding water-reducer plasticizer and a specified additional quantity of cement. The results have shown that for a limited range of plasticizer percentage, and a fixed value of additional cement, the compressive strength has reached reasonable value. This paper treats of the effect of using recycled aggregates on the tensile strength of concrete, where concrete results from the special composition defined by our previous work. The aim is to determine the relationship between the compressive and tensile strength of recycled concrete.

Experimental Study on the Effect of Recycled Aggregate and GGBS on Flexural Behaviour of Reinforced Concrete Beam

2016 ◽  
Vol 857 ◽  
pp. 101-106
Author(s):  
P.R. Deepa ◽  
Joy Anup
Keyword(s):  
Experimental Study ◽  
Raw Materials ◽  
Reinforced Concrete Beam ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Partial Replacement ◽  
Concrete Aggregate ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

Globally, the concrete industry consumes large quantities of natural resources, which are becoming insufficient to meet the increasing demands. Cement and aggregates are major constituents of concrete. Utilisation of waste materials in concrete instead of raw materials reduces environmental pollution. Ground-granulated blast-furnace slag (GGBS) is a by-product of steel industry. It has cementatious property. Recycled aggregates are obtained from demolishing waste. By using recycled concrete aggregate and GGBS in concrete we can reduce environmental problem to some extent. This experimental study evaluate the effective utilisation of GGBS and recycled aggregate in concrete. In this study GGBS is used as partial replacement for cement and recycled aggregate as partial replacement for coarse aggregate.

scholarly journals Estimating the Circularity Performance of an Emerging Industrial Symbiosis Network: The Case of Recycled Plastic Fibers in Reinforced Concrete

2021 ◽  
Vol 13 (18) ◽  
pp. 10257
Author(s):  
Simona Marinelli ◽  
Maria Angela Butturi ◽  
Bianca Rimini ◽  
Rita Gamberini ◽  
Miguel Afonso Sellitto
Keyword(s):  
Construction Industry ◽  
Circular Economy ◽  
Cement Mortar ◽  
Raw Materials ◽  
Life Stage ◽  
Industrial Symbiosis ◽  
Effective Strategy ◽  
Construction Sector ◽  
Artificial Turf ◽  
Synthetic Fibers

In recent times, the construction industry has been handling circular economy strategies in order to face the most important challenges in the sector, namely the lack of raw materials and the environmental impacts derived from all the processes linked to the entire supply chain. The industrial symbiosis approach represents an effective strategy to improve the circularity of the construction industry. This study analyses the circularity performance of an emerging industrial symbiosis network derived from the production of a cement mortar reinforced with recycled synthetic fibers coming from artificial turf carpets. From the collection of artificial turf carpets at the end-of-life stage it is possible to recover several materials, leading to potential unusual interactions between industries belonging to different sectors. A suitable indicator, retrieved from the literature, the Industrial Symbiosis Indicator (ISI), has been used to estimate the level of industrial symbiosis associated with increasing materials recirculation inside the network. Four scenarios—ranging from perfect linearity to perfect circularity—representing growing circularity were tested. Findings demonstrate that the development of an effective industrial symbiosis network can contribute to improving the circular approach within the construction sector, reducing environmental and economic pressures.

scholarly journals CO2 mineralization of demolished concrete wastes into a supplementary cementitious material – a new CCU approach for the cement industry

2021 ◽  
Vol 6 ◽  
pp. 53-60
Author(s):  
Maciej Zajac ◽  
Jan Skocek ◽  
Jørgen Skibsted ◽  
Mohsen Ben Haha
Keyword(s):  
Silica Gel ◽  
Cement Paste ◽  
Cementitious Material ◽  
Cement Industry ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Supplementary Cementitious Material ◽  
Co2 Mineralization ◽  
Concrete Recycling ◽  
Composite Cements

This contribution discusses the carbon capture and utilization (CCU) approach based on CO2 mineralization of cement paste from recycled concrete as new approach to capture CO2 and significantly contribute to the reduction in CO2 emissions associated with cement production. The current literature suggests that all CO2 released from the decomposition of limestone during clinker production can be sequestered by carbonation of the end-of-life cement paste. This carbonation can be achieved in a few hours at ambient temperature and pressure and with a relatively low CO2 concentration (< 10 %) in the gas. The carbonation of cement paste produces calcite and an amorphous alumina-silica gel, the latter being a pozzolanic material that can be utilized as a supplementary cementitious material. The pozzolanic reaction of the alumina-silica gel is very rapid as a result of its high specific surface and amorphous structure. Thus, composite cements containing carbonated cement paste are characterized by a rapid strength gain. The successful implementation of this CCU approach relies also on improved concrete recycling techniques and methods currently under development to separate out the cement paste fines and such. Full concrete recycling will further improve the circular utilization of cement and concrete by using recycled aggregates instead of natural deposits of aggregates.  Although the feasibility of the process has already been demonstrated at the industrial scale, there are still several open questions related to optimum carbonation conditions and the performance of carbonated material in novel composite cements.

scholarly journals Assessment of recycled concrete aggregate properties required for structural concretes

2019 ◽  
Vol 262 ◽  
pp. 06010
Author(s):  
Marek Węglorz ◽  
Andrzej Ajdukiewicz ◽  
Alina Kliszczewicz
Keyword(s):  
Structural Engineering ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Concrete Aggregate ◽  
Aggregate Concrete ◽  
Recycled Concrete Aggregates ◽  
University Of Technology ◽  
Concrete Recycling

Assessment of recycled aggregate concrete (RAC) properties by laboratory tests is still required due to lack of precise guidelines and with taking into account slightly different behaviour of such concretes in comparison with natural aggregate concretes (NAC). It is especially important when recycled concrete aggregates are used for the structural elements. In this paper, the following rules for the whole concrete recycling cycle were defined: (1) rules for examination of original concretes selected for recycling and (2) rules for aggregate preparation and their fractionize as well as design rules for recycled aggregate concrete mixtures (including required tests of recycled aggregates and concrete properties). Requirements towards recycled aggregate concrete formulated in this paper are based on the long term experience and research works on the RAC which were held by A. Ajdukiewicz and A. Kliszczewicz in the Department of Structural Engineering of the Silesian University of Technology, practically since 1995.

scholarly journals Recycling Aggregates for Self-Compacting Concrete Production: A Feasible Option

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 868 ◽  
Author(s):  
Rebeca Martínez-García ◽  
M. Ignacio Guerra-Romero ◽  
Julia M. Morán-del Pozo ◽  
Jorge de Brito ◽  
Andrés Juan-Valdés
Keyword(s):  
High Performance ◽  
Physical And Mechanical Properties ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Concrete Aggregate ◽  
Structural Elements ◽  
The European Union ◽  
Self Compacting Concrete ◽  
Concrete Production ◽  
Complex Structural

The use of construction and demolition wastes (C&DW) is a trending future option for the sustainability of construction. In this context, a number of works deal with the use of recycled concrete aggregates to produce concrete for structural and non-structural purposes. Nowadays, an important number of C&DW management plants in the European Union (EU) and other countries have developed robust protocols to obtain high-quality coarse recycled aggregates that comply with different European standards in order to be used to produce new concrete. The development of self-compacting concrete (SCC) is another way to boost the sustainability of construction, due to the important reduction of energy employed. Using recycled aggregates is a relatively recent scientific area, however, studies on this material in the manufacture of self-compacting concrete have proven the feasibility thereof for conventional structural elements as well as high-performance and complex structural elements, densely reinforced structures, difficult-to-access formwork and difficult-to-vibrate elements. This paper presents an original study on the use of coarse recycled concrete aggregate (CRA) to obtain self-compacting concrete. Concrete with substitution ratios of 20%, 50% and 100% are compared with a control concrete. The purpose of this comparison is to check the influence of CRA on fresh SCC as well as its physical and mechanical properties. The parameters studied are material characterization, self-compactability, compressive strength, and tensile and flexural strength of the resulting concrete. The results conclude that it is feasible to use CRA for SCC production with minimal losses in the characteristics.

scholarly journals Verification of a Torsional Behaviour Prediction Model for Reinforced Recycled Aggregate Concrete Beams

2022 ◽  
Vol 2022 ◽  
pp. 1-13
Author(s):  
Aqeel H. Chkheiwer ◽  
Mazin A. Ahmed ◽  
Zahir M. N. Hassan
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Reinforced Concrete Beams ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Cross Sectional ◽  
Recycled Concrete Aggregates ◽  
Concrete Recycling

This study shows the torsional conduct of aggregate streaming beams of reinforced concrete recycling. Pure torsion was perceived for 15 reinforced concrete beams containing recycled concrete aggregates. The beams were grouped into five lengths and cross-sectional groups. The study’s principal parameters were the various percentages of longitudinal steel reinforcement and the proportions of recycled aggregates. The beams were purely twisted until failure and investigated for torsional and crack behaviour. The findings show that the beams with maximum steel enhancement and standard aggregate exhibited maximum cracking power and ultimate torsional strength. Recycled aggregates increased the presence of splitting and the ultimate strength, and the effects of steel strengthening in recycled beams were apparent. In a second analysis, the whole torsional reaction of the beams was analytically predicted. A soft truss model was used and matched with test results for standard beams. A strong compromise was generally reached.

Effect of Recycled Concrete Aggregates and Natural Pozzolana on Rheology of Self-Compacting Concrete

2014 ◽  
Vol 600 ◽  
pp. 256-263 ◽  
Author(s):  
Said Kenai ◽  
Belkacem Menadi ◽  
Amina Debbih ◽  
El Hadj Kadri
Keyword(s):  
Rheological Properties ◽  
High Volume ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Fresh Properties ◽  
Self Compacting Concrete ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Natural Pozzolana ◽  
Natural Aggregates

Self-compacting concrete (SCC) is a very fluid concrete in which its compaction can take place under the effect of its own weight, without vibration. SCC is characterized by its high volume of paste, and the use of superplasticizers. Very little work is reported in the literature on the use of recycled aggregates in SCC. The main objective of this paper is to study the effect of coarse and fine recycled concrete aggregates on the fresh properties of SCC, by substitution of either 100% or 50% of natural aggregates by recycled aggregates. The effect of substitution of 15% by weight of cement of natural pozzolana on the fresh properties of SCC is also studied. The results have shown that the substitution of 50% or 100% of natural aggregates by recycled concrete aggregates gives SCC with very comparable rheological properties to that of the reference SCC. However, SCC with recycled aggregates are less stable against bleeding. The addition of natural pozzolana decreases workability for both SCC with natural aggregates or with recycled aggregates.

scholarly journals Assessment of environmental impact of coarse aggregates substitution by crushed pavements in concrete mixtures

2020 ◽  
Vol 322 ◽  
pp. 01036
Author(s):  
Jan Kočí ◽  
Jan Fořt ◽  
Václav Kočí ◽  
Izabela Hager
Keyword(s):  
Environmental Impacts ◽  
Building Materials ◽  
Raw Materials ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Primary Sources ◽  
Concrete Pavements ◽  
Material Recycling ◽  
Coarse Aggregates ◽  
Transport Emissions

Inefficient use of end-of-life materials in combination with depletion of primary sources can be understood as a significant factor that motivates to effective waste material recycling and reuse. Since the construction industry produces millions of tons of building materials, which are continuously reaching their service life end, there is a great potential for their reuse instead of simple landfilling. In this light, concrete is a versatile building material that might incorporate lots of recycled building materials as it is demanding on primary sources. A substitution of coarse aggregates by recycled products is, therefore, one of the ways how to mitigate these environmental burdens. This paper aims at evaluation of environmental contributions of concrete with coarse aggregates being substituted by crushed concrete pavements. Various amounts of recycled aggregates were assumed (0%, 50%, and 100%) to reveal the environmental impacts. The analysis incorporates all inputs and outputs related to the production of concrete and recycling of concrete pavements (raw materials production, processing, transport emissions, energy production, etc.). The results indicate that substitution of coarse aggregates by recycled concrete pavements may bring significant mitigation of environmental impacts and hence it deserves further investigation.

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