Influence of recycled fine aggregate on microstructure and hardened properties of concrete

Kumar, R. Raghunandan; Gurram, Subash Chandra Bose; Minocha, A.K.

doi:10.1680/jmacr.17.00030

Cited by 51 publications

(20 citation statements)

References 30 publications

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“…Regarding the mixes whose composition included 25% cMRA (M4) and 50% cMRA (M7), it is worth noting that they registered a small decrease of 7.0% and 4.6% compared with M1, respectively. These losses are similar to those registered by Cantero et al [ 30 ] in concretes with 25% and 50% of mixed recycled aggregate and lower than the 12% and 14% losses registered previously by other authors who [ 70 , 71 , 72 , 73 , 74 , 75 ] analysed concretes with 100% of recycled aggregates, which had 10% ≤ Rb ≤ 14%.…”

Section: Resultssupporting

confidence: 90%

The Design and Development of Recycled Concretes in a Circular Economy Using Mixed Construction and Demolition Waste

et al. 2021

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This research study analysed the effect of adding fine—fMRA (0.25% and 50%)—and coarse—cMRA (0%, 25% and 50%)—mixed recycled aggregate both individually and simultaneously in the development of sustainable recycled concretes that require a lower consumption of natural resources. For this purpose, we first conducted a physical and mechanical characterisation of the new recycled raw materials and then analysed the effect of its addition on fresh and hardened new concretes. The results highlight that the addition of fMRA and/or cMRA does not cause a loss of workability in the new concrete but does increase the amount of entrained air. Regarding compressive strength, we observed that fMRA and/or cMRA cause a maximum increase of +12.4% compared with conventional concrete. Tensile strength increases with the addition of fMRA (between 8.7% and 5.5%) and decreases with the use of either cMRA or fMRA + cMRA (between 4.6% and 7%). The addition of fMRA mitigates the adverse effect that using cMRA has on tensile strength. Regarding watertightness, all designed concretes have a structure that is impermeable to water. Lastly, the results show the feasibility of using these concretes to design elements with a characteristic strength of 25 MPa and that the optimal percentage of fMRA replacement is 25%.

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Section: Resultssupporting

confidence: 90%

The Design and Development of Recycled Concretes in a Circular Economy Using Mixed Construction and Demolition Waste

et al. 2021

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“…Many previous studies have presented that the compressive strength of recycled concrete mixed with a certain proportion of fine recycled concrete aggregates (FRCAs) is greatly reduced due to the large water absorption rate of FRCAs [ 27 , 28 , 29 ]. Additionally, the adverse effect of FRCAs on concrete is greater than that of coarse recycled concrete aggregates (CRCAs) [ 30 ].…”

Section: Methodsmentioning

confidence: 99%

Experimental Study on the Mechanical Properties and Compression Size Effect of Recycled Aggregate Concrete

Zhao

Xiao

et al. 2021

Materials

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To explore the basic mechanical properties and size effects of recycled aggregate concrete (RAC) with different substitution ratios of coarse recycled concrete aggregates (CRCAs) to replace natural coarse aggregates (NCA), the failure modes and mechanical parameters of RAC under different loading conditions including compression, splitting tensile resistance and direct shear were compared and analyzed. The conclusions drawn are as follows: the failure mechanisms of concrete with different substitution ratios of CRCAs are similar; with the increase in substitution ratio, the peak compressive stress and peak tensile stress of RAC decrease gradually, the splitting limit displacement decreases, and the splitting tensile modulus slightly increases; with the increase in the concrete cube’s side length, the peak compressive stress of RAC declines gradually, but the integrity after compression is gradually improved; and the increase in the substitution ratio of the recycled aggregate reduces the impact of the size effect on the peak compressive stress of RAC. Furthermore, an influence equation of the coupling effect of the substitution ratio and size effect on the peak compressive stress of RAC was quantitatively established. The research results are of great significance for the engineering application of RAC and the strength selection of RAC structure design.

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“…e total replacement of fine RCA to the normal aggregate produces a decrease in compressive, splitting tensile, and flexural strengths of about 14, 6, and 23%, respectively. e microstructural investigation of fine RCA concrete reveals more unhydrated cement particles and less dense calcium silicate hydrate gel than in normal fine aggregate concrete [22,23].…”

Section: Introductionmentioning

confidence: 92%

Bricks and Concrete Wastes as Coarse and Fine Aggregates in Sustainable Mortars

Mobili

Giosuè

Corinaldesi

et al. 2018

Advances in Materials Science and Engineering

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The total substitution by volume of natural coarse calcareous aggregate by coarse recycled brick aggregate (RBA) and coarse recycled concrete aggregate (RCA) has been investigated to produce more sustainable and environment-friendly mortars. Aggregates were also partially substituted by their fines at 12.5% by volume. Mortars have been tested in terms of mechanical, microstructural, and durability properties. Results show that it is feasible to replace a natural calcareous aggregate entirely by recycled aggregates. In particular, the obtained mortars, even if more porous and more prone to the water capillary absorption than that manufactured with natural aggregates, result in less stiffness and thus are less subjected to crack formation, more permeable to water vapour, and less susceptible to sulphate attack.

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Influence of recycled fine aggregate on microstructure and hardened properties of concrete

Cited by 51 publications

References 30 publications

The Design and Development of Recycled Concretes in a Circular Economy Using Mixed Construction and Demolition Waste

The Design and Development of Recycled Concretes in a Circular Economy Using Mixed Construction and Demolition Waste

Experimental Study on the Mechanical Properties and Compression Size Effect of Recycled Aggregate Concrete

Bricks and Concrete Wastes as Coarse and Fine Aggregates in Sustainable Mortars

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