Initial moisture and mixing effects on higher quality recycled coarse aggregate concrete

Brand, Alexander S.; Roesler, Jeffery R.; Salas, Andrés

doi:10.1016/j.conbuildmat.2015.01.047

Cited by 129 publications

(49 citation statements)

References 33 publications

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“…Lightweight aggregate (LWA) was used widely in concrete as internal curing materials to reduce autogenous shrinkage with a lower propensity for early-age cracking [4,5]. However, the initial moisture of the LWA also influences the properties of concrete at both the fresh state and the hardened state [4,6,7]. Recently, the use of SAP in concrete has been studied to limit the internal relative humidity decrease and the autogenous shrinkage [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Influence of Bottom Ashes with Different Water Retainabilities on Properties of Expansive Mortars and Expansive Concretes

Nguyen¹,

Saengsoy²,

Tangtermsirikul³

2019

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This study investigates the influence of bottom ashes with different water retainabilities as an internal curing material on the performances of mixtures containing an expansive additive and fly ash. Two series of experiments were conducted: mortar containing expansive agent (expansive mortar) with a controlled w/b ratio and concrete containing expansive agent (expansive concrete) with a controlled initial slump. Test results indicate that workability of expansive mortar is improved due to retained water of bottom ash. Compressive strength of expansive mortar with bottom ash decreases. Total shrinkage of the expansive mortars, with a constant w/b, increases with the use of bottom ashes that have high water retainability in the condition of 7 days of water curing and then air curing. However, by using bottom ashes, compressive strength increases when the slump of the expansive concrete is controlled due to decrease of w/b ratio. The internal curing ability of bottom ashes leads to enhanced expansion of expansive mortars with sealed curing and expansive concretes with moist curing, reducing total shrinkage of expansive mortars with air curing. It was found by DTG analysis that expansive concretes with higher expansion containing bottom ash with higher water retainability had a higher amount of ettringite.

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Section: Introductionmentioning

confidence: 99%

Influence of Bottom Ashes with Different Water Retainabilities on Properties of Expansive Mortars and Expansive Concretes

Nguyen¹,

Saengsoy²,

Tangtermsirikul³

2019

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“…Although most authors conclude that shrinkage increases up to 35-80% in concrete with 100% recycled aggregate (2,49,62,77,78), a few have stated that this concrete may show similar shrinkage deformations to that obtained in conventional concrete, even with replacement ratios of 100%, when using high-quality recycled aggregate or different mixing methods (10,69,79,80). Kou et al (10) analysed the effect of using recycled aggregates with different water absorption coefficients and composition.…”

Section: Shrinkagementioning

confidence: 99%

“…When replacement get up to 50%, the shrinkage deformations in RC are 13-33% higher than those registered in conventional concretes. In general, shrinkage grows as the replacement ratio increases (2,6,69,78,80,82,83). …”

Section: Shrinkagementioning

confidence: 99%

“…where ε c1 is the strain at peak stress and ε c is the strain in compression Collecting the data of different authors (2,6,10,56,69,77,78,80,82,83) Figure 14 analyses the relationship "RC's shrinkage-reference concrete's shrinkage" taking into account different ratios of coarse recycled aggregate, from 20% to 100%. This figure confirms that the recycled aggregate ratio influences the shrinkage gain.…”

Section: Shrinkagementioning

confidence: 99%

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Recycled concrete with coarse recycled aggregate. An overview and analysis

González-Fonteboa

Seara-Paz

Brito³

et al. 2018

Mater. construcc.

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ABSTRACT:The construction field has contributed to environmental degradation, producing a high amount of construction and demolition waste (C&D waste) and consuming large volumes of natural resources. In this context, recycled concrete (RC) has been recognised as a means to preserve natural resources and reduce space for waste storage. During the last decades, many researchers have developed works studying different recycled concrete properties.This review focuses on structural RC made with coarse recycled aggregate from concrete waste. The main objective is to provide a state of the art report on RC's properties and an analysis on how to predict them taking into account relevant research works. Moreover, the study tries to collect and update RC findings, proposing equations to define RC's performance, in terms of mechanical strength, modulus of elasticity, stress-strain, creep and shrinkage. RESUMEN:Hormigón reciclado con árido grueso reciclado. Una visión general y análisis. El campo de la construcción ha contribuido a la degradación del medio ambiente, produciendo gran cantidad de residuos de construcción y demolición y consumiendo grandes volúmenes de recursos naturales. En este contexto, el hormigón reciclado se ha presentado como una opción para preservar los recursos naturales y reducir el espacio destinado a vertedero. Así, durante las últimas décadas, muchos investigadores han desarrollado trabajos para estudiar las propiedades del hormigón reciclado.Este artículo se centra en el hormigón estructural fabricado con árido reciclado grueso procedente de residuos de hormigón. El principal objetivo es desarrollar un estado del arte que recoja las principales propiedades del hormigón reciclado y un análisis de cómo calcularlas teniendo en cuenta un gran número de trabajos relevantes en este ámbito. Adicionalmente, el estudio recopila y actualiza el conocimiento sobre estos hormigones, proponiendo ecuaciones que permitan definir sus resistencias mecánicas, módulo de elasticidad, tensión-deformación, fluencia y retracción.

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“…As the aggregate size decreases, the Los Angeles coefficient increases (meaning a decrease in abrasion resistance). This is due to the fact that the fine fractions have a higher percentage of attached mortar than the coarse kind (19). However, in this case, high scatter can be observed.…”

Section: Abrasion Resistancementioning

confidence: 51%

Study of recycled concrete aggregate quality and its relationship with recycled concrete compressive strength using database analysis

2016

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This work studies the physical and mechanical properties of recycled concrete aggregate (recycled aggregate from concrete waste) and their influence in structural recycled concrete compressive strength. For said purpose, a database has been developed with the experimental results of 152 works selected from over 250 international references.The processed database results indicate that the most sensitive properties of recycled aggregate quality are density and absorption. Moreover, the study analyses how the recycled aggregate (both percentage and quality) and the mixing procedure (pre-soaking or adding extra water) influence the recycled concrete strength of different categories (high or low water to cement ratios). When recycled aggregate absorption is low (under 5%), pre-soaking or adding extra water to avoid loss in workability will negatively affect concrete strength (due to the bleeding effect), whereas with high water absorption this does not occur and both of the aforementioned correcting methods can be accurately employed. RESUMEN: Estudio de la calidad del árido reciclado y su relación con la resistencia a compresión del hormigón reciclado utilizando una base de datos.El estudio analiza las propiedades físico-mecánicas de los áridos reciclados de hormigón (procedentes de residuos de hormigón) y su influencia en la resistencia a compresión del hormigón reciclado estructural. Para ello se ha desarrollado una base de datos con resultados de 152 trabajos seleccionados a partir de más de 250 referencias internacionales.Los resultados del tratamiento de la base indican que densidad y absorción son las propiedades más sensibles a la calidad del árido reciclado. Además, este estudio analiza cómo el árido reciclado (porcentaje y calidad) y el procedimiento de mezcla (presaturación o adición de agua extra) influyen en la resistencia del hormigón reciclado de diferentes categorías (alta o baja relación agua-cemento). Cuando la absorción es baja (inferior al 5%) presaturar o añadir agua para evitar pérdidas de trabajabilidad afectan negativamente a la resistencia (debido al bleeding), mientras que cuando es alta esto no sucede y ambos métodos son adecuados.

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Initial moisture and mixing effects on higher quality recycled coarse aggregate concrete

Cited by 129 publications

References 33 publications

Influence of Bottom Ashes with Different Water Retainabilities on Properties of Expansive Mortars and Expansive Concretes

Influence of Bottom Ashes with Different Water Retainabilities on Properties of Expansive Mortars and Expansive Concretes

Recycled concrete with coarse recycled aggregate. An overview and analysis

Study of recycled concrete aggregate quality and its relationship with recycled concrete compressive strength using database analysis

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