Water absorption and electrical resistivity of concrete with recycled concrete aggregates and fly ash

Kurda, Rawaz; Silvestre, José Dinis

doi:10.1016/j.cemconcomp.2018.10.004

Cited by 228 publications

(79 citation statements)

References 93 publications

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“…The interest in using building construction materials with better mechanical, durability, and environmental characteristics is continuously growing [1][2][3][4][5][6]. However, to obtain such properties, particularly in cement-based materials, some non-conventional raw materials (such as fly ash (FA) and recycled aggregates (RA)), with unknown hazard levels, are being incorporated.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Ecotoxicological Potential of Fly Ash and Recycled Concrete Aggregates Use in Concrete

et al. 2020

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This study applies a methodology to evaluate the ecotoxicological potential of raw materials and cement-based construction materials. In this study, natural aggregates and Portland cement were replaced with non-conventional recycled concrete aggregates (RA) and fly ash (FA), respectively, in the production of two concrete products alternative to conventional concrete (used as reference). The experimental program involved assessing both the chemical properties (non-metallic and metallic parameters) and ecotoxicity data (battery of tests with the luminescent bacterium Vibrio fischeri, the freshwater crustacean Daphnia magna, and the yeast Saccharomyces cerevisiae) of eluates obtained from leaching tests of RA, FA, and the three concrete mixes. Even though the results indicated that RA and FA have the ability to release some chemicals into the water and induce its alkalinisation, the respective eluate samples presented no or low levels of potential ecotoxicity. However, eluates from concrete mixes produced with a replacement ratio of Portland cement with 60% of FA and 100% of natural aggregates and produced with 60% of FA and 100% of RA were classified as clearly ecotoxic mainly towards Daphnia magna mobility. Therefore, raw materials with weak evidences of ecotoxicity could lead to the production of concrete products with high ecotoxicological potential. Overall, the results obtained highlight the importance of integrating data from the chemical and ecotoxicological characterization of materials’ eluate samples aiming to assess the possible environmental risk of the construction materials, namely of incorporating non-conventional raw materials in concrete, and contributing to achieve construction sustainability.

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Section: Introductionmentioning

confidence: 99%

Evaluation of the Ecotoxicological Potential of Fly Ash and Recycled Concrete Aggregates Use in Concrete

et al. 2020

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“…Therefore, the net increase in pores volume causes the increase in permeable porosity and sorptivity coefficient of the composite material. Kurda et al [8] also reported that the inclusion of fine RCA was harmful to concrete in terms of water absorption characteristics of product composite. NS up to 3% reduces both permeable porosity and sorptivity coefficient.…”

Section: Permeable Porosity and Sorptivity Coefficientmentioning

confidence: 99%

Effect of aqueous sodium silicate on properties of recycled aggregate mortar

Ali

2019

SN Appl. Sci.

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This study investigates the influence of sodium silicate (Na 2 SiO 3) (NS) on the strength and durability performance of recycled concrete aggregate bearing mortar (RAM). NS is used as 0%, 1%, 2%, 3%, 4%, and 5% by weight of cement in RAM. Natural aggregate mortar (NAM) serving as control mix is also produced using natural sand. Compressive strength, sorptivity coefficient, apparent porosity, chloride penetration, and mass loss due to H 2 SO 4 are investigated at various ages. Experimental results indicate that RAM shows inferior strength and durability properties compared to NAM. RAM with 2-3% NS shows 4-9% higher compressive strength than NAM. 2-3% NS also improves the durability of RAM by significantly reducing water sorptivity and permeable porosity compared to corresponding blank mix. RAM shows significant mass loss due to H 2 SO 4 attack compared to NAM, whereas, RAM with 2-4% NS shows acid attack resistance comparable to that of the NAM. Based on experimental results, it can be established that RAM with 2-3% NS can outperform NAM by noticeable margin in strength-durability-economic performance. Keywords Recycled concrete aggregate (RCA) • Sodium silicate (Na 2 SiO 3) • Compressive strength • Sorptivity coefficient • Chloride penetration • Acid attack on mortar

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“…The combined influence of FA and RCA on mechanical performance [17,18] and durability [19] of concrete have been investigated, and these studies showed that higher incorporation levels of FA and RCA were detrimental to strength, but FA improves long-term durability performance of concrete.…”

Section: Introductionmentioning

confidence: 99%

“…The economy is an important aspect of concrete, and studies on the investigation of combined economic and strength performance of concrete made with both FA and RCA are very rare. Although studies are available that deal with combined use of FA and RCA on strength and durability of concrete [17,19,20], literature on economic impact of using these materials in concrete is very scarce. Therefore, this study not only investigate the combined effect of FA and RCA (of class F type) on strength and durability properties of concrete, but also a detailed economic impact of FA and RCA on concrete considering its strength is presented in this paper.…”

Section: Introductionmentioning

confidence: 99%

Mechanical, durability and economic performance of concrete incorporating fly ash and recycled aggregates

Nawaz

Qureshi

Ali³

et al. 2020

SN Appl. Sci.

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This paper studies the impact of replacing natural coarse aggregates (NCA) with recycled coarse aggregates (RCA) and cement (OPC) with fly ash (FA), on properties and economy of concrete. RCA was obtained by crushing old concrete specimens. FA of low calcium type was used to partially replace OPC. A total of nine concrete mixes (including a reference mix) were prepared using 50% RCA, and 100% RCA with four different levels of FA (0% FA, 10% FA, 20% FA, 30% FA). Workability, fresh density, compressive strength, apparent porosity, and bulk density was measured to evaluate the performance of each mixture. Mixes with optimum levels of both RCA and FA reaching the compressive strength potential of reference mix at 90 days, were subjected to chloride migration testing. To ascertain the combined impact of RCA and FA on economic and strength performance of concrete, a cost to strength ratio (CSR) analysis was also performed on all mixes. Results of testing indicate that FA compensates the loss in workability of fresh concrete and improve the compressive strength of RCA concrete at 28 and 90 days. Negative influence of RCA on density and porosity is minimized by consumption of FA in concrete. Mixes with 50% RCA and 20-30% FA show better resistance against chloride penetration compared to that of the reference mix. CSR analysis suggests that FA must be used along with RCA in concrete in order to minimize the negative influence of RCA on both cost and strength.

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Water absorption and electrical resistivity of concrete with recycled concrete aggregates and fly ash

Cited by 228 publications

References 93 publications

Evaluation of the Ecotoxicological Potential of Fly Ash and Recycled Concrete Aggregates Use in Concrete

Evaluation of the Ecotoxicological Potential of Fly Ash and Recycled Concrete Aggregates Use in Concrete

Effect of aqueous sodium silicate on properties of recycled aggregate mortar

Mechanical, durability and economic performance of concrete incorporating fly ash and recycled aggregates

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