Quantification of the residual mortar content in recycled concrete aggregates by image analysis

Abbas, A.; Fathifazl, Gholamreza; Fournier, Benoît; Isgor, O. Burkan; Zavadil, Renata; Razaqpur, A. Ghani; Foo, Simon

doi:10.1016/j.matchar.2009.01.010

Cited by 171 publications

(59 citation statements)

References 4 publications

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Section: Calibration For Probability Distribution Of Old Attached Mormentioning

confidence: 99%

“…A number of researchers Abbas et al 2009) have investigated the content of old adhesive mortar in RCA. Abbas et al (2009) investigated the distribution of the residual mortar content of RCA by the method of image analysis, which served as a quality control tool for such aggregates and which provided an accurate measurement of the residual mortar content in recycled aggregates. The average frequency of the RCA particles corresponds to four types of residual mortar distribution: A [RCA-MO (4.75-9.5 mm fraction)]; B [RCA-VA (4.75-9.5 mm fraction)]; C [RCA-VA (9.5-12.7 mm fraction)] and D [RCA-VA (12.7-19 mm fraction)].…”

Section: Calibration For Probability Distribution Of Old Attached Mormentioning

confidence: 99%

See 1 more Smart Citation

On Probability Distribution of Chloride Diffusion Coefficient for Recycled Aggregate Concrete

Ying

Xiao

Meng

2016

Int J Concr Struct Mater

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In predicating the probability distribution of chloride diffusion coefficient of recycled aggregate concrete (D RAC ), the morphological characteristics of three phases, i.e., the old attached mortar, the natural aggregate and the new mortar, should all be taken into account. The present paper attempts to develop a probability density evolution method (PDEM) to achieve this. After verifying the derived PDEM results with experimental results, the effects of old attached mortar to the D RAC are examined in a quantitative manner. It is found that (1) the variation of the attached mortar content is much sensitive to D RAC ; (2) given the probability distribution of the content and chloride diffusion coefficient of old mortar, the probability distribution of D RAC can be analysed based on the PDEM; and (3) the critical chloride diffusion coefficient at a certain assurance rate can be obtained by the PDEM. The analysis results of this investigation will be valuable to the durability design for RAC.

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Section: Calibration For Probability Distribution Of Old Attached Mormentioning

confidence: 99%

Section: Calibration For Probability Distribution Of Old Attached Mormentioning

confidence: 99%

On Probability Distribution of Chloride Diffusion Coefficient for Recycled Aggregate Concrete

Ying

Xiao

Meng

2016

Int J Concr Struct Mater

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“…Recycled concrete aggregates (RCA) are composed of an intimate mix between aggregates and hardened cement paste [7][8][9][10]. The fine fraction of RCA (FRCA), essentially composed of mortar and hardened cement paste, possesses a large water demand which makes it harder to recycle into concrete and mortar compared to coarser RCA [11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Influence of fine recycled concrete aggregates on the properties of mortars

Zhao

Rémond

Damidot

et al. 2015

Construction and Building Materials

239

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h i g h l i g h t sInfluences of saturation state of FRCA on the mortars' properties are studied. Mortars made with dried FRCA present larger slump and better mechanical properties. Compressive strength of mortars decreases quasi linearly with substitution rate. Fraction 0/0.63 mm of FRCA has a worse effect on mechanical properties of mortars. a r t i c l e i n f o b s t r a c tFine recycled concrete aggregates (FRCA) also called recycled sand, having particle sizes smaller than 5 mm, are essentially composed of mortar and hardened cement paste. Therefore they induce a large water demand which makes them hard to recycle into mortar and concrete. In this paper, the properties of mortars containing FRCA have been studied, including fresh properties, mechanical properties and interfacial transition zone (ITZ) microstructure.The influence of saturation state of FRCA (dried or saturated) on the properties of mortars of identical compositions has first been studied. The results showed that the slump of mortars containing dried FRCA is always larger than that of mortars containing saturated FRCA. Indeed, in the case of dried FRCA, the theoretical amount of absorbed water is added at the beginning of mixing leading to a temporary increase of the initial efficient W/C ratio and volume of paste, leading to a better workability before its absorption into FRCA. On the contrary, the absorbed water in saturated FRCA is not readily available and thus cannot contribute to increase the initial efficient W/C ratio. Moreover, the compressive strength of mortars containing dried FRCA is always larger than that of mortars made with saturated FRCA, which is attributed to a thinner interfacial transition zone improving its mechanical properties. The influence of the fraction of recycled sand and of the granular class of recycled sand on the mechanical properties of mortars has then been studied with saturated FRCA. The compressive strength of mortars decreases quasi linearly as the replacement percentage of recycled sand increases. Moreover, it is shown that the finer fraction of recycled sand (0/0.63 mm) has the worse effect on the mechanical properties of mortars.

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“…Freezing and thawing with natural water, freezing and thawing with a sodium sulphate solution (22), hydrochloric acid dissolution and thermal attack (23) were tried.…”

Section: Attached Mortar Contentmentioning

confidence: 99%

Diseño de mezclas de hormigón reciclado mediante el método Volumen de Mortero Equivalente (EMV): Validación bajo el contexto español y su adaptación al método de diseño de Bolomey

Jiménez¹,

Aponte²,

Vázquez³

et al. 2012

Mater. construcc.

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A new method for proportioning recycled aggregates concrete (RAC) is used to check its feasibility under the Spanish context. First, an extensive experimental campaign has been done, with the purpose of check and analyze the applicability of the EMV method with two Spanish recycled concrete aggregates (RCA). The aim of the second part of the investigation, was to elaborate an adaptation of the EMV method to Bolomey methodology (1), using a 20% weight replacement of coarse natural aggregates (NA) for RCA, and so, with this, comply with the Spanish Instruction for Structural Concrete (EHE 2008). Slump, air content, fresh and hardened densities, compressive strength and modulus of elasticity were determined and analyzed, in order to check the concrete properties. Finally, it was observed that, the EMV method is viable, and its adaptation, results in concrete mixes with similar or better properties than the natural aggregate concrete and RAC conventionally prepared.Keywords: recycled concrete; recycled aggregate; mix proportioning; mechanical properties; Portland cement.( * ) Universidad Politécnica de Cataluña (Barcelona, España).Persona de contacto / Corresponding author: cristian.jimenez@estudiant.upc.edu RESUMENEl nuevo método para el diseño de hormigón con árido reciclado (HAR) es usado para comprobar su posibilidad de uso bajo el contexto español. Primeramente, se realiza una extensa campaña experimental, para analizar las posibilidades de su aplicación, usando dos áridos reciclados de hormigón (ARH) españoles. En la segunda etapa se elabora una adaptación del método a la metodología propuesta por Bolomey (1), con 20% de reemplazo en peso de árido grueso natural (AN) por ARH, para así cumplir con las recomendaciones estipuladas en la Instrucción de Hormigón Estructural (EHE 2008). Para determinar y analizar las propiedades del hormigón, se llevaron a cabo ensayos de asentamiento, contenido de aire, densidades, módulo elástico y resistencias a compresión. Finalmente, se concluye que el uso del nuevo método es viable, y que su adaptación produce hormigones con similares o mejores características que los elaborados para hormigón con árido convencional (HAC) y HAR convencionales.

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Quantification of the residual mortar content in recycled concrete aggregates by image analysis

Cited by 171 publications

References 4 publications

On Probability Distribution of Chloride Diffusion Coefficient for Recycled Aggregate Concrete

On Probability Distribution of Chloride Diffusion Coefficient for Recycled Aggregate Concrete

Influence of fine recycled concrete aggregates on the properties of mortars

Diseño de mezclas de hormigón reciclado mediante el método Volumen de Mortero Equivalente (EMV): Validación bajo el contexto español y su adaptación al método de diseño de Bolomey

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