Use of recycled fine aggregate in concretes with durable requirements

Zega, Claudio Javier; Maio, Ángel Antonio Di

doi:10.1016/j.wasman.2011.06.011

Cited by 263 publications

(108 citation statements)

References 13 publications

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“…The capillary water absorption of concretes produced with RMA showed much higher values than those of conventional concretes, throughout all the concrete series, this was probably due to the connectivity of the porous in each grain of the coarse mixed aggregate, a fact which has also been reported by other researchers [30,31] [43, 44,45].…”

Section: Durability Properties 331 Capillary Water Absorptionsupporting

confidence: 72%

Properties of Plain Concrete Produced Employing Recycled Aggregates and Sea Water

Etxeberria

Gonzalez-Corominas

2017

Int J Civ Eng

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Highlights:The use of Recycled Mixed Aggregates (RMA) leads to a reduction of landfills growthThe use of seawater represents another advance in sustainability by reducing fresh water consumption Analysis of the possibility of using RMA and seawater in the production of concrete to be used in port sitesThe use of seawater in concretes with type III cement produced a denser cement matrix, which suffered low decrease by RMA addition. AbstractThe generation of construction and demolition waste (C&DW) is a noteworthy environmental and economic concern. The development of new applications in which Recycled Mixed Aggregates (RMA) can be used will lead to a reduction of landfills growth. Moreover, the use of seawater shall represent another advance in sustainability due to the consequent reduction of fresh water consumption, which can be a limited resource in certain areas. Although seawater is not generally recommended for concrete production, especially in reinforced concretes, seawater could be a viable replacement for fresh water in the production of plain concretes. This study intends to analyse the possibility of using RMA and seawater in the production of concrete to be used in port sites. This study is based on 3 different parameters: cement class, water source and RMA content. The results highlighted the beneficial effects of using type III cement, especially with regard to durability properties. The concretes produced employing RMA and type III cement achieved lower value of sorptivity coefficient and higher values of ultrasonic pulse velocity (UPV), chloride ion penetration resistance and electrical resistivity than those produced with natural aggregates and type I cement. Moreover the use of seawater in concretes with type III cement not only produced higher density and lower absorption capacity but also higher mechanical properties by creating a denser cement matrix, which proved to suffer low decrease by RMA addition.Key words: mixed recycled aggregate, sea water, blast furnace cement, recycled concrete, properties INTRODUCTIONConstruction and demolition waste (C&DW) generation is a major economic and environmental concern for European Union countries, as it represents the heaviest and most voluminous waste streams [1]. C&DW still registers low recycling ratios, especially in Southern European countries. In these countries C&DW is commonly comprised of several different materials such as concrete, old raw aggregates, ceramic bricks and gypsum. Following their treatment in a recycling plant the recycled aggregates sourced from this type of C&DW are designated as recycled mixed aggregate (RMA) [2][3][4]. This mixed aggregate, while being comprised of a much greater percentage of ceramic material and other impurities has comparatively only a small percentage of concrete and raw aggregates. Currently most of RMA used in the construction industry are employed in low-strength required applications, such as road sub-base layers.The use of RMA in concrete production has mainly been studied for non-structural eleme...

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Section: Durability Properties 331 Capillary Water Absorptionsupporting

confidence: 72%

Properties of Plain Concrete Produced Employing Recycled Aggregates and Sea Water

Etxeberria

Gonzalez-Corominas

2017

Int J Civ Eng

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“…Several countries already enforce regulations that encourage its use and define the percentage of natural aggregates to be replaced by recycled aggregates 13 . The initial results for the fine fraction of these recycled aggregates (size below 4 mm) were not promising, which led some codes and technical specifications to strongly advise against the use of such materials in concrete because of the problems it may cause during mixing and in the hardened state 14 .…”

Section: Introductionmentioning

confidence: 99%

“…As the availability of FNA and dumping grounds for the unused fine fraction of the C&DW decreased, the study of FRA gained new momentum, with various researchers obtaining satisfactory results 14,[20][21][22] . To obtain concrete with good characteristics made with FRA it is paramount to know their properties in detail before use.…”

Section: Introductionmentioning

confidence: 99%

A new method to determine the density and water absorption of fine recycled aggregates

2013

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The construction industry keeps on demanding huge quantities of natural resources, mainly minerals for mortars and concrete production. The depletion of many quarries and environmental concerns about reducing the dumping of construction and demolition waste in quarries have led to an increase in the procuring and use of recycled aggregates from this type of waste. If they are to be incorporated in concrete and mortars it is essential to know their properties to guarantee the adequate performance of the end products, in both mechanical and durability-related terms. Existing regulated tests were developed for natural aggregates, however, and several problems arise when they are applied to recycled aggregates, especially fine recycled aggregates (FRA). This paper describes the main problems encountered with these tests and proposes an alternative method to determine the density and water absorption of FRA that removes them. The use of sodium hexametaphosphate solutions in the water absorption test has proven to improve its efficiency, minimizing cohesion between particles and helping to release entrained air.

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“…So, natural concrete absorption is more than twice that of the RC absorption, which could be attributed to the lower content of pores interconnected in recycled concretes. Most studies report a greater absorption of water in the Study of potential advantages of pre-soaking on the properties of pre-cast concrete made with recycled coarse aggregate • 9 case of concrete made with RCA as a result of the incorporation of a more porous material such as cement paste adhering to the aggregate (33,54,55). However, studies such as that of Gencel et al (30) report reductions of 62%, similar to those obtained in this study, with a similar coarse fraction replacement in the manufacture of concrete paving blocks.…”

Section: Water Absorptionmentioning

confidence: 99%

“…However, the concrete must be sufficiently workable to facilitate the use of moulds, and in this respect the higher water absorption of RA may be a limiting factor. In this case workability can be improved by the use of plasticizers or by increasing the amount of mixing water, thereby reducing mechanical strength (33).…”

Section: Introductionmentioning

confidence: 99%

Study of potential advantages of pre-soaking on the properties of pre-cast concrete made with recycled coarse aggregate

et al. 2016

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Recycled aggregate (RA) from construction and demolition waste is traditionally used for the manufacture of concrete for different applications. Due primarily to high water content required by RA, the quality of the concrete is determined by the amount of replacement RA. The aim of this study is to determine if RA pre-soaking enhances the properties of pre-cast concrete for street furniture, with low mechanical and structural requirements, in which 100% of the coarse fraction is replaced. The results of physical and mechanical tests performed on concrete specimens in which the RA was pre-soaked using five different methods applied are compared with a reference concrete sample and a concrete sample made with non-pre-soaked RA. The results show that non-pre-soaked RA offers improved physical-mechanical properties for pre-cast concrete, except for the workability; problems arising from poorer workability could be improved with the use of plasticizers, which can be easily included in the production process. RESUMEN: Estudio de las ventajas potenciales del premojado en las propiedades del hormigón prefabricado con árido reciclado grueso.El árido reciclado (AR) procedente de residuos de construcción y demolición se utiliza tradicionalmente en la elaboración de hormigón para diferentes aplicaciones. Debido principalmente al mayor contenido en agua requerido por el AR, la calidad del hormigón está determinada por la cantidad de AR reemplazado. El objetivo de este estudio es determinar si el AR premojado mejora las propiedades del hormigón prefabricado para mobiliario urbano, con bajas exigencias mecánicas y estructurales, en el que se sustituye el 100% de la fracción gruesa. Los resultados de los ensayos físicos y mecánicos realizados sobre muestras de hormigón en las cuales el AR se ha premojado usando cinco métodos diferentes se han comparado con una muestra de hormigón de referencia y una muestra de hormigón fabricada con AR no premojado. Los resultados muestran que el AR no premojado proporciona propiedades físico-mecánicas mejoradas en el hormigón prefabricado, a excepción de la trabajabilidad; los problemas derivados de una deficiente trabajabilidad pueden ser fácilmente corregidos con la incorporación de plastificantes en el proceso de fabricación.

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Use of recycled fine aggregate in concretes with durable requirements

Cited by 263 publications

References 13 publications

Properties of Plain Concrete Produced Employing Recycled Aggregates and Sea Water

Properties of Plain Concrete Produced Employing Recycled Aggregates and Sea Water

A new method to determine the density and water absorption of fine recycled aggregates

Study of potential advantages of pre-soaking on the properties of pre-cast concrete made with recycled coarse aggregate

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