A review on treatment techniques to improve the durability of recycled aggregate concrete: Enhancement mechanisms, performance and cost analysis

Bahraq, Ashraf A.; Jose, Jobin; Shameem, Mohammed; Maslehuddin, Mohammed

doi:10.1016/j.jobe.2022.104713

Cited by 32 publications

(21 citation statements)

References 198 publications

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“…However, none of them evaluates the practicality of these techniques based on technical, economic and environmental analysis. For example, Makul (2021), Sivamani et al (2021), Bahraq et al (2022) conducted a thorough review study on the current RCA treatment techniques. However, each method's economic, environmental and technical characteristics have not been studied.…”

Section: Introductionmentioning

confidence: 99%

A review of the advanced treatment techniques for enriching the recycled concrete aggregates for recycled-based concrete: economic, environmental and technical analysis

Nikmehr

Kafle

Al-Ameri

2023

SASBE

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PurposeThis study aimed to review various existing methods for improving the quality of recycled concrete aggregates (RCAs) as a possible substitution for natural aggregates (NAs) in concrete. It is vital as the old paste attached to the RCA weakens its structure. It is due to the porous structure of the RCA with cracks, weakening the interfacial transition zone (ITZ) between the RCA and binding material, negatively impacting the concrete's properties. To this end, various methods for reinforcement of the RCA, cleaning the RCA's old paste and enhancing the quality of the RCA-based concrete without RCA modification are studied in terms of environmental effects, cost and technical matters. Furthermore, this research sought to identify gaps in knowledge and future research directions.Design/methodology/approachThe review of the relevant journal papers revealed that various methods exist for improving the properties of RCAs and RCA-based concrete. A decision matrix was developed and implemented for ranking these techniques based on environmental, economic and technical criteria.FindingsThe identified methods for reinforcement of the RCA include accelerated carbonation, bio deposition, soaking in polymer emulsions, soaking in waterproofing admixture, soaking in sodium silicate, soaking in nanoparticles and coating with geopolymer slurry. Moreover, cleaning the RCA's old paste is possible using acid, water, heating, thermal and mechanical treatment, thermo-mechanical and electro-dynamic treatment. Added to these treatment techniques, using RCA in saturated surface dry (SSD) mixing approaches and adding fibres or pozzolana enhance the quality of the RCA-based concrete without RCA modification. The study ranked these techniques based on environmental, economic and technical criteria. Ultimately, adding fibres, pozzolana and coating RCA with geopolymer slurry were introduced as the best techniques based on the nominated criteria.Practical implicationsThe study supported the need for better knowledge regarding the existing treatment techniques for RCA improvement. The outcomes of this research offer an understanding of each RCA enrichment technique's importance in environmental, economic and technical criteria.Originality/valueThe practicality of the RCA treatment techniques is based on economic, environmental and technical specifications for rating the existing treatment techniques.

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Section: Introductionmentioning

confidence: 99%

A review of the advanced treatment techniques for enriching the recycled concrete aggregates for recycled-based concrete: economic, environmental and technical analysis

Nikmehr

Kafle

Al-Ameri

2023

SASBE

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“…Cement-based materials derivatives are used extensively in the building because of their affordability and durability [ 4 – 6 ]. Retaining their quality, mechanical performance, and functionality after being exposed to external conditions is a hallmark of durable cement-based materials [ 7 – 9 ]. Cement-based material’s durability is measured by how long it lasts while being subjected to chemical attacks, abrasion, weathering, and other forms of deterioration [ 10 – 12 ].…”

Section: Introductionmentioning

confidence: 99%

Evaluating the compressive strength of glass powder-based cement mortar subjected to the acidic environment using testing and modeling approaches

et al. 2023

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This study conducted experimental and machine learning (ML) modeling approaches to investigate the impact of using recycled glass powder in cement mortar in an acidic environment. Mortar samples were prepared by partially replacing cement and sand with glass powder at various percentages (from 0% to 15%, in 2.5% increments), which were immersed in a 5% sulphuric acid solution. Compressive strength (CS) tests were conducted before and after the acid attack for each mix. To create ML-based prediction models, such as bagging regressor and random forest, for the CS prediction following the acid attack, the dataset produced through testing methods was utilized. The test results indicated that the CS loss of the cement mortar might be reduced by utilizing glass powder. For maximum resistance to acidic conditions, the optimum proportion of glass powder was noted to be 10% as cement, which restricted the CS loss to 5.54%, and 15% as a sand replacement, which restricted the CS loss to 4.48%, compared to the same mix poured in plain water. The built ML models also agreed well with the test findings and could be utilized to calculate the CS of cementitious composites incorporating glass powder after the acid attack. On the basis of the R2 value (random forest: 0.97 and bagging regressor: 0.96), the variance between tests and forecasted results, and errors assessment, it was found that the performance of both the bagging regressor and random forest models was similarly accurate.

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“…RAC can realize the recycling of waste concrete, reduce the mining of natural resources and construction waste landfill, and has broad engineering application prospects 2,3 . Compared with natural coarse aggregate (NCA), recycled coarse aggregate (RCA) has more edges and corners, and a great deal of old mortar attached on its surface 4,5 . In addition, there is a great deal of micro‐cracks formed in RCA because of the damage accumulation in the early crushing process of waste concrete.…”

Section: Introductionmentioning

confidence: 99%

“…attached on its surface. 4,5 In addition, there is a great deal of micro-cracks formed in RCA because of the damage accumulation in the early crushing process of waste concrete. As a result, RCA has the characteristics of large porosity, high water absorption, low bulk density, high crushing index, and high micro-powder content.…”

mentioning

confidence: 99%

Flexural stiffness of recycled aggregate concrete beams under combined effect of load and steel corrosion

Wang

Qin

2023

Structural Concrete

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Since reinforced concrete members suffer from different types of loads during their service life, the steel bars embedded in reinforced concrete members can be easily corroded in chloride‐laden environment. To investigate the influence of combined effect of load and steel corrosion on the flexural stiffness of recycled aggregate concrete (RAC) beams, 12 RAC beams were prepared and tested. The effects of load level (i.e., the ratio of the load applied to beams to the ultimate load) and recycled coarse aggregate (RCA) replacement ratio (i.e., the ratio of RCAs to replace natural coarse aggregates) on the internal force arm coefficient of cracking cross‐section, the elastoplastic resistance moment coefficient of cross‐section, and the strain incongruity coefficient of corroded tensile steel bars were analyzed, and a calculation model for flexural stiffness of RAC beams under combined effect of load and steel corrosion was established. The results showed that when the ratio of bending moment to ultimate bending moment of the pure bending part of beams was within 0.55–0.80 and the average mass loss of tensile steel bars was less than 3.23%, 0.85 could be adopted as the internal force arm coefficient of cracking cross‐section. The elastoplastic resistance moment coefficient of cross‐section was approximately a constant when the corroded RAC beams were in the service stage, while it increased obviously with the load level. There was a strong linear relationship between strain incongruity coefficient and average mass loss of tensile steel bars during the service stage of corroded RAC beams, and the strain incongruity coefficient increased linearly with the load level. The calculated values of the model of flexural stiffness proposed in this paper were in reasonable agreement with the experimental values.

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A review on treatment techniques to improve the durability of recycled aggregate concrete: Enhancement mechanisms, performance and cost analysis

Cited by 32 publications

References 198 publications

A review of the advanced treatment techniques for enriching the recycled concrete aggregates for recycled-based concrete: economic, environmental and technical analysis

A review of the advanced treatment techniques for enriching the recycled concrete aggregates for recycled-based concrete: economic, environmental and technical analysis

Evaluating the compressive strength of glass powder-based cement mortar subjected to the acidic environment using testing and modeling approaches

Flexural stiffness of recycled aggregate concrete beams under combined effect of load and steel corrosion

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