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The durability of concrete containing recycled aggregates, sourced from concrete specimens that have been tested in laboratory testing facilities, remains understudied. This paper aims to present the results of experiments investigating the effect of incorporating such type of concrete waste on the strength and durability-related properties of concrete.

A total of 77 concrete cylinders sized Ø100 × 200 mm with varying amount of recycled concrete aggregate (RCA) (0%–100% by volume, at 25% increments) and maximum aggregate size (12.5, 19.0 and 25.0 mm) were fabricated and tested for slump, compressive strength, sorptivity and electrical resistivity. Disk-shaped specimens, 50-mm thick, were cut from the original cylinders for sorptivity and resistivity tests. Analysis of variance and post hoc test were conducted to detect statistical variability among the data.

Compared to regular concrete, a reduction of slump (by 18.6%), strength (15.1%), secondary sorptivity (31.5%) and resistivity (17.0%) were observed from concrete containing 100% RCA. Statistical analyses indicate that these differences are significant. In general, an aggregate size of 19 mm was found to produce the optimum value of slump, compressive strength and sorptivity in regular and RCA-added concrete.

The results of this study suggest that comparable properties of normal concrete were still achieved by replacing 25% of coarse aggregate volume with 19-mm RCA, which was processed from laboratory-tested concrete samples. Therefore, such material can be considered as a potential and sustainable alternative to crushed gravel for use in light or nonstructural concrete construction.

This 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.

The 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.

The 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.

The 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.

The practicality of the RCA treatment techniques is based on economic, environmental and technical specifications for rating the existing treatment techniques.

The current study intends to synthesise the prior studies on employability skills among work-ready professionals in higher education through bibliometric and network visualisation tools. This study also identifies the gaps in the existing literature that still need to be filled and maps the course for future investigation.

The current study examined research papers on employability skills among work-ready professionals in higher education to evaluate global patterns and the top authors, institutions, journals, and nations contributing to this field. The authors analysed eight hundred eighty-five papers from the Scopus database between 1982 and 2023 for the study. Open-source bibliometric tools like Biblioshiny were used in the study to examine the body of literature and to spot new directions for future research.

The study’s findings indicate that since 2008, researchers, academics, and policymakers have paid more attention to employability skills among work-ready professionals, and 2019 is the year seeing the highest no. of publications. Across the globe, 2077 authors contributed to the articles, papers, and journals published in the particular domain. Regarding location, the United Kingdom is the world’s most productive nation, with 342 articles produced. Similarly, Australia, India, and Malaysia are the leading nations that have contributed to the field. Both keywords significantly contribute to scientific knowledge.

The gaps in this study will serve as a reference point for researchers conducting future studies in this field. Additionally, the result of this analysis offers a roadmap for higher education to enhance graduate employability by embedding necessary skills into them.

There has not been a bibliometric analysis concerning employability skills among Work-ready professionals in the existing literature; hence, this article is innovative. This study is the first attempt at integrating the concept. The study also gives an overview of potential directions for future research in this discipline.