Optimum mix design of recycled concrete based on the fresh and hardened properties of concrete

Bidabadi, Mehran Shirani; Akbari, Mahmood; Panahi, Omid

doi:10.1016/j.jobe.2020.101483

Cited by 40 publications

(42 citation statements)

References 52 publications

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“…Authorities were worked on identifying a struggle process with the huge mass of waste concrete and offered environmental solutions for the use of waste concrete in newly manufactured concrete as recycled aggregate (RA) taking measures such as regulation and standards for RA [ 1 ]. Environmental approaches giving zero harm to the nature, recycling materials, and preserving natural resources so to the economic development have been defined as main aim by countries [ 2 ]. However, the authorities faced difficulties to act laws, regulations, and measures on the use of RA in concrete and it is emerged as a need to form a new code for recycled aggregate concrete (RAC) while present concrete codes have been developed for natural aggregate concrete (NAC).…”

Section: Introductionmentioning

confidence: 99%

Mineral Addition and Mixing Methods Effect on Recycled Aggregate Concrete

Dilbas

Güneş

2021

Materials

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This paper presents influence of treatment and mixing methods on recycled aggregate concretes (RAC) designed regarding various techniques. Absolute Volume Method (AVM) according to TS 802, Equivalent Mortar Volume Method (EMV), silica fume (SF) as a mineral addition were considered in the design of concretes. In total, four groups of concretes were produced in the laboratory: 1) natural aggregate concrete (NAC) designed with AVM as control concrete, 2) RAC designed with AVM as control RAC, 3) RAC with SF as a mineral addition designed with AVM as treated RAC and 4) RAC designed with EMV as treated RAC. The tests were performed at 28th days and the statistical analysis were made on the test results. According to the results, EMV and SF increased the compressive strength of concretes and this resulted an increase in the strength class of concrete. A significant statistical difference between the concretes were determined. According to multiple comparison analysis, it was found that especially there was a significant relationship among NAC, RAC and RAC-EMV. In addition, it was recommended that EMV and AVM with 5% SF could be used in the design of RAC rather than AVM only to achieve the target strength class C30/37.

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Section: Introductionmentioning

confidence: 99%

Mineral Addition and Mixing Methods Effect on Recycled Aggregate Concrete

Dilbas

Güneş

2021

Materials

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“…To gain a better insight into the use of concrete with recycled aggregate, a brief literature review was made, which included analysis of previous laboratory tests of mixes with various percentages of recycled aggregate in the composition, and theoretical studies. The same literature review revealed that it is possible to substitute both fine and coarse aggregates with recycled aggregates in proportions ranging from 0 to 100 % [9][10][11][12][13][14][15][16][17][18][19][20][21]. Variations are possible due to various purity levels of recycled aggregate, and various material properties.…”

Section: Influence Of Recycled Aggregate On Concrete Propertiesmentioning

confidence: 99%

Construction of a new day hospital in Zadar using recycled aggregate concrete

Baričević¹,

Kovač²,

Didulica³

2021

JCE

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This paper presents the pilot project of application of recycled aggregate during construction of a new day hospital in Zadar. The project included the demolition of an existing hospital building and the use of generated construction waste as recycled aggregate in the construction of a part of the building. The 16/32 mm fraction of aggregate was obtained by mechanical processing of the generated waste which was then tested in accordance with the HRN EN 206 and HRN EN 12620 standards. Four concrete mixes were prepared, and the fresh (slump, density, air content) and hardened properties were tested (compressive strength, modulus of elasticity, capillary absorption, water permeability, drying shrinkage). The obtained results confirm that by complying with the standards for recycled aggregates and knowing their origin it is possible to produce concrete with properties equivalent to those of ordinary concrete for specified durability conditions.

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“…These C&DWs cause serious environmental loads. The demand of NA results in overexploitation and shortage of NA resources, which greatly damages the ecological balance of aggregate-producing areas [1,2]. Utilizing these C&DWs as recycled aggregates to prepare the recycled aggregate concrete (RAC) is an effective and proven method to solve the environmental and resource crises and realize a circular economy in conventional concrete industries [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Effect of Freeze–Thaw Cycles on Carbonation Behavior of Three Generations of Repeatedly Recycled Aggregate Concrete

et al. 2021

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Multiple recycling of waste concrete has attracted widespread attention. This study presented the carbonation behavior of repeatedly recycled aggregate concrete (RRAC) used in a micro-frozen region. The effects of freeze–thaw cycles on the carbonation depth of three generations of RRAC with 25%, 75%, and 100% of replacement rate were evaluated. All RRAC specimens after different numbers of freeze–thaw cycles were rapidly carbonated for 28 d indoors to test the carbonation resistance of concrete. The results suggested that the carbonation depth of RRAC subjected to freeze–thaw cycles is higher than that in the non-freeze–thaw condition. This is because the freeze–thaw damages cause the internal structure of RRAC to become porous and and prone to cracking, thus providing convenient channels for CO2 to react with the alkali in the cementitious materials. With the growth of replacement rate or recycling number, RRAC reveals serious freeze–thaw damage and inferior carbonation resistance, which is due to the continuous deterioration repeatedly recycled concrete aggregate (RRCA) quality. However, when the replacement rate was 25%, the carbonation depth for the third generation of RAC was comparable to the second generation of RAC at a 75% replacement rate, and even the first generation of 100% RAC. To ensure better carbonation resistance durability of multiple recycling RAC, the low replacement rate of RRCA should be considered. For the third generation of RAC with the 100% replacement rate, its highest carbonation depth after freeze–thaw cycles was 9.16 mm, which still met the design requirements for structural use in a micro-frozen region. This indicates that it is feasible for three generations of RRAC to be used in the micro-frozen environment and that RRAC has great engineering application potential and promotional value.

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Optimum mix design of recycled concrete based on the fresh and hardened properties of concrete

Cited by 40 publications

References 52 publications

Mineral Addition and Mixing Methods Effect on Recycled Aggregate Concrete

Mineral Addition and Mixing Methods Effect on Recycled Aggregate Concrete

Construction of a new day hospital in Zadar using recycled aggregate concrete

Effect of Freeze–Thaw Cycles on Carbonation Behavior of Three Generations of Repeatedly Recycled Aggregate Concrete

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