Impact of Concrete Quality on Sustainability Assignment Sample

Chapter 1: Introduction

1.1 Introduction

The growing awareness of the environment in the global society has forced the construction field to look for ways to decrease its effect on the environment. Recycled concrete can be used in constructions as another solution towards the reduction of construction waste and /or the utilization of natural resources. This paper aims at determining whether recycled concrete could be used in the construction projects in place of fresh concrete. This research analyzes the structural quality, durability, and overall performance of recycled concrete through laboratory tests. The findings of this research will be useful in understanding its applicability in practice and promoting the improvement of environmentally conscious construction practices. This dissertation provides the fundamental knowledge on the potential environmental and economic benefits of RC in the construction industry for MSC of AC, thus providing the basis for sustainable development of new products and building materials.

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1.2 Background of the Study

The construction industry is one of the most significant global consumers of resources that resultantly bring about environmental damage and pollution. Since concrete is one of the most widely used construction materials, the ways that it is produced and then disposed of have also caused significant environmental issues (Küpfer et al. 2023). Ordinary concrete is, in turn, composed of sand, gravel, and limestone in equal measures and its production covers a large part of the CO2 emissions. Also, the dumping of concrete after demolition in the landfills further complicates construction waste management, which is a serious concern for sustainable development.

Recycled concrete however has rapidly developed into a viable option that can be palatable to the principles of sustainability. This entails the recycling of concrete waste into aggregates that can be reused in construction projects (Makul et al. 2021). While the idea is theoretically powerful, application of the concept has presented several problems, such as concerns regarding strength, durability, and construction compliance.

This research seeks to address the following question as part of the broader understanding of the reuse of concrete recycled in construction. In the experiments the research assesses key properties like the compressive strength, workability and the durability of the material, in relation to the conventional building materials. These findings are also important in helping to improve the knowledge of the practical use and possible drawbacks of the use of recycled concrete, whilst the results can aid the reassurance of a continuation of an efficient recycling system, beneficial information for industries and local governments (Morón et al. 2021).

1.2 Aim

The objective of the research is to present the potential of applying concrete from recycled waste in construction by carrying out testing and analysis on the structures and performance of the material. This study endeavours to establish whether recycled concrete can provide satisfactory performance for present construction standards while promoting sustainability and minimising waste management (Badraddin et al. 2021). The aim of this work is to identify the strengths, durability, and environmental utility of Recycled Concrete and give recommendations concerning its applicability to construction projects. Thus, filled in the gap between theoretical and practical evidence, this study seeks to advance existing knowledge concerning recycled concrete reuse, advance environmental sustainability as it applies to construction industry, and respond to global concerns that include scarcity and consumption of resources as well as management of waste.

1.4 Objectives

• To examine the physical and mechanical characteristics such as concrete compressive strength and toughness of recycled concrete through experiments.
• To investigate and evaluate the effectiveness of using recycled concrete in construction projects in comparison to normal concrete in the areas of structural strength and usability.
• In order to examine the effectiveness of the claims made about the positive environmental impacts of RC in construction citing waste minimization as well as resource conservation.
• To establish the problems that construction designers face when using recycled concrete and suggest how these problems can be addressed.

1.5 Research Questions

What are the properties of Recycled concrete and How are they different from Normal concrete?

What is the effect of using recycled concrete in the composition of this study on the compressive strength as determined by various proportions of recycled aggregates?

What are the advantages of using recycle concrete in construction focusing on waste minimization and resource management?

What hurdles keep recycled concrete from being used more often in construction, and how can these hurdles be overcome?

What sort of measure and recommendations should be provided to engineers and architects to improve the application of recycled concrete in today construction practices?

1.6 Research Hypothesis

Positive Hypotheses (H0)

In experimental conditions, recycled concrete can possess similar compressive strength comparable to that of the normal concrete.

Recycled concrete has become popular because of the benefits it has on the environment; reduced dump site and the preservation of natural resources.

In sustainability the use of Recycled concrete in construction minimizes the impact that the construction industry has on the environment.

Quality control proves adequate to address the longevity issues of recycled concrete for long term construction projects.

Lifespan Concrete Crusher can also be relatively cheaper than traditional production of concrete.

The general use of RC can help to decrease reliance on natural aggregates.

Recycled concrete is as good as virgin material in existing construction procedures without reducing quality.

Processing technology enhance the quality and the performance parameters of recycled concrete aggregates.

Negative Hypotheses (H1)

Recycled concrete is known to lack the compressive strength of the new concrete under some circumstances.

Energy costs involved in recycling process eliminate most environmental attributes of concrete.

The use of recycled concrete elicits magnitude of sustainability issues since the material serves in variable qualities.

The application of recycled concrete in construction may be threatened by inadequate quality control in the production process.

Recycled concrete is several time s costlier than the normal material due to processing and transportation charges.

Lack of enough supply of recycled concrete makes its use as a Natural aggregate substitute a viable one.

Integrated recycled concrete weakens construction projects in existing practice.

Ineffectively recycled concrete aggregates exhibit performance restrictions on recycled concrete aggregates.

1.7 Research Rationale

The evolution of the global construction industry demands identification of efficient and environmentally friendly ways of construction as opposed to the conventional resource consumptive practices (Muda et al. 2023). Widespread in construction projects, concrete is nevertheless the result of the extraction of natural resources and has a major carbon footprint. More importantly, the removal of demolished concrete also expands the landfill waste. Such issues justify the reasons to look for extraordinary measures, including the use of recycled concrete that at the same time eliminates two problems, ly waste disposal and resources utilization.

This research will aim at examining the possibility of using recycled concrete, to replace normal construction materials. In this research, laboratory experiments are carried out to analyse the structural and environmental efficiency of the recycled concrete, and to narrow the gap between the results of the researches and real life usage of the given material (de Andrade et al. 2020). The study is beneficial for the global sustainable development goals as well as the attempts to make the construction industry more environmentally friendly (Kashyap et al. 2022). The purpose of this research is in the social relevance of the research theme, which by endorsing the use of recycled material in construction, affirms that concrete from this source meets the industry requirement. It also provides insights on the economic and technical viability of recycled concrete for construction which will be useful data for those formulating policies and practice (Küpfer et al. 2022).

1.8 Research Significance

The importance of this research lies in the fact that it discusses the use of recycled concrete as an opportunity to revolutionise construction industry through solving major ecological and economic issues. The construction industry behind the depletion of resources and the generation of as much waste as any other and this research affords a positive solution in this trend (Badraddin et al. 2022). This paper offers a valuable insight into how waste material in the construction industry can be effectively utilised to meet structural performance and environmental needs in the construction industry today through the assessment of recycled concrete.

A consequence of the current study is that recommendations arising from the research are beneficial to aiding the practice of construction in embracing recycled concrete. This can help to cut down on virgin material dependence and lower costs of construction while helping to keep ecological impact minimized. Besides, the findings give an understanding of the difficulties that arise with the utilization of RCA, which directs the stakeholders on how to overcome these difficulties using innovative approaches and polices.

1.9 Research Framework

Figure 1: Research Framework

(Source: Self-created)

1.10 Conclusion

This introduction chapter creates the background necessary for examining the application of RCR in construction as a solution to major environmental and economic concerns. In achieving this, the chapter presents the research aim, objectives, hypotheses, rationale, and significance to reemphasise the need for sustainable practices within the construction industry. The study objectives seek to assess the viability, efficiency, and sustainability attributes of the recycled concrete via intense laboratory analyses. This work aims to extend knowledge of the scope of application of recycled concrete as well as offer recommendations for its implementation. It provides the background that leads to a more inclusive evaluation of sustainability in current construction methodologies.

Chapter 2: Literature review

2.1 Introduction

This paper aims at reviewing literature regarding recycled concrete and its use in construction with special emphasis on physical/mechanical properties, structural performance, environmental consideration as well as the drawbacks. Based on the study’s objective to promote both the use and effectiveness of Recycled concrete, the secondary data has been critically reviewed based on diverse literature sources and historical reviews such as past theses and scholars’ opinions. The objectives include testing the concrete made from recycled material’s compressive strength, the factors of its construction application, its environmental benefits, and challenges. Hence, the review aims at systematically integrating various findings in order to provide insights on the gaps in knowledge and potential development of the enhanced utilization of recycled concrete in sustainable construction.

2.2 Empirical study

Topic 1: Physical and Mechanical Properties of Recycled Concrete

Gao et al. 2020, mentioned, RCA has received a lot of interest from various stakeholders as an Eco friendly material, reducing the further deterioration of natural resources as well as solving construction waste disposal problem. Nonetheless, the mechanical properties of recycled aggregate concrete, commonly referred to as RAC, are usually lower than the mechanical properties of natural aggregate concrete or NAC with regard to strength, toughness and durability. The lower performance of RAC is attributed to interfacial transition zone, which is more porous and carries high micro cracking because of mortar presence on RCA.To improve these properties, a number of approaches were investigated including the use of nano-materials like nano-SiO₂, nano-CaCO₃, and carbon nanotubes (CNTs)(Author version RCA Nano).

Analyzing the evaluation of the ITZ confirms that the interfacial transition zone is crucial in establishing the general strength and service life of RAC (Berredjem et al. 2020). While NAC has one ITZ, RAC has 3 – between the recycled aggregates, the new cement paste, and the old mortar – that makes the structure inherently weaker. Specifically, recent incorporation of nano-materials has revealed enhanced densification of these ITZs. For example Nano-SiO₂ reacts with micro-voids and also enhances the hydration reaction to improve cement matrix strength. The authors said that incorporation of nano-SiO₂ raised the compressive strength of RAC by about 16.8 percent with great dispersal methods such as ultrasonication and surfactant processes.

Another influential parameter that impact the efficiency of RAC is the replacement ratio of aggregate from recycled material. Higher replacement ratios showed decrease in compressive and tensile strength because of the high porosity and water absorption of the aggregates used. However, modifications in the formation of materials at nano level have done much to counter these reductions. For instance, the use of CNTs enhanced tensile strength while reducing shrinkage features that make RAC more applicable in structural applications as explained below. The works mentioned above stated that two stage mixing approach (TSMA) enhanced the compressive strength by 20.3 % and optimized the dispersion of nano-SiO₂ and CNTs(Author version RCA Nano).

However, some of the following challenges are still apparent if the use of nano-material is to be scaled up in RAC. As for the challenges, for instance, cost, nanoparticle agglomeration, or even dosage used in a specific investigation call for additional research in the future. Some of the researchers state it by pointing out that even though nano-technology has advanced RAC’s mechanical properties to a certain level, the most crucial aspects that need to be addressed by authorities and worldwide institutions are the quality and performance fluctuations(Revilla-Cuesta et al. 2020). The use of nano-materials to integrate the wall structure is a major development towards eradicating the constraints of RAC. By increasing the compressive strength, tensile strength and durability, nano-technology make the use of recycled concrete in the construction industry possible and present with the world trends for green construction.

Topic 2: Structural Performance and Usability of Recycled Concrete in Construction Projects

Aboutalebi Esfahani et al. 2020 included, Recycled concrete aggregate’s (RCA) structural characteristics and application in construction projects have attracted interest in light of limited resources and environmental concerns. The actual feasibility of RCA as a replacement of natural aggregates depends on its mechanical properties and conformity to standards as well as compatibility with construction processes. It is important to note that subsequent processing methods such as crushing and sieving have however been pointed out by researchers as necessary in increasing RCA’s usability in subbase and base constructions in construction projects.

It is difficult to establish the average strength and durability of concrete from recycled materials because CandD waste is heterogeneous in nature. RCA depends on such parameters such as aggregate gradation, water absorption, and mortar residues affecting mechanical performance tremendously (Omer et al. 2022). They also show how incorporation of cement stabilizers into the mix in order to enhance its composition increases the compressive an tensile strengths of RCA to a level suitable for structural use. They also note that field trials of embankments should attain satisfactory performance by ensuring compaction and material homogeneity.

The benefits for the environment further enrich the set of structural advantages of RCA. Using waste concrete aggregates in construction projects will help cut the amount of waste that ends up in the landfill and the carbon footprint. Nevertheless, workability issues remain, especially regarding achieving the necessary criteria for use in load-carrying structures (Aytekin and Mardani-Aghabaglou, 2022). Researchers observes that RCA mixtures can meet the technical requirement for subbase courses, but their suitability in base courses requires modification with native aggregates to achieve appropriate resilient modulus.

Nevertheless, RCA has proved to be quite versatile in some circumstances. The paper includes several examples from Spain and the Netherlands to demonstrate that RCA is effective in road construction, noting that CTGMs can have improved modulus of elasticity or compressive strength (Zucconi et al. 2022). These findings indicate that RCA could be a viable and efficient material for application in infrastructure projects if proper quality control measures are adopted during the processing and utilization of the material. The use of recycled concrete in structural performance and usability depends on the limitations of CandD waste variability and improvement in concrete processing.

Figure 2: Use of recycled concrete aggregates

(Source: https://www.mdpi.com/ )

Topic 3: Environmental Impact of Recycled Concrete in Construction

According to the views of Makul et al. 2021, The usage of RCA maximises sustainability within the construction industry In Construction Industry. Authors noted, the replacement of NCA with RCA play a crucial role in environmental conservation due to the conservation of the scarce resource and reduction in landfill volumes. The use of urban construction waste mainly from the demolition of aged structures through incorporating them in structural concrete, helps to solve significant ecological problems like high costs of urban landfilling, and scarcity of land resources (Zengfeng et al. 2020). This change points to RCA’s ability to support the elimination of waste and optimization of resource utilization- two core principles of sustainable development. The principal environmental advantages that RCA has been able to offer are therefore based on the capacity of the process to reduce virgin materials dependency. According to different researches, the recycling of RCA in concrete production lowers the need for natural aggregates, thus mitigating the negative impacts of extraction on the environment (Tam et al. 2021). Also, RCA manufacturing concerns itself with such urban concerns as demolition waste. Researchers points that the European individuals contribute to over 850 million tons of construction waste each year with the same trends recorded internationally which calls for recycling strategies within construction waste.

Some issues remain relevant to the further enhancement of the environmental benefits of RCA. Stating that RCA concretes are usually characterised by higher water absorption and lower densities than those of NCA concretes, researchers like Fediuk et al. also emphasize the fact that RCA concretes’ mechanical properties often suffer due to such characteristics of RCA material, and this is why RCA concretes have not gained extensive use. To overcome these problems the use of treatments like pre-soaking of RCA in pozzolanic liquids and replacement of the RCA with supplementary cementitious materials like fly ash and silica fume has been suggested. These methods do not only increase properties such as durability and mechanical strength of RCA but also helps decreasing emissions of greenhouse gas during production processes.

Economically, RCA has a low cost when compared to virgin aggregates especially in areas where transportation of natural materials is expensive or the source is remote (Huang et al. 2020). This analysis of RCA proves the financial feasibility of the choice making the position of RCA even stronger for the construction industry. The research works indicate that RCA in high-strength structural concrete application coupled with state-of-art processing technology offers similar or even better performance as opposed to regular aggregates but with a reduced environmental impact.

Nevertheless, the present innovations show that RCA is yet to take its rightful position due to reluctance from manufactures and construction firms. This reticence can be blamed on the unpredictability of the quality of the recycled aggregates and the disparity in the utilization of recycling materials. To overcome these barriers, more research and development should be undertaken with the support of policymakers and construction industry players to develop credible benchmarks for RCA and popularize its use in construction practices. Constructing RCA for buildings enjoy numerous environmental advantages over standard construction techniques that should address big issues as the environmental management of wasted and the conservation of resources. Exploring new opportunities by breaking through previous constraints using technological advances and legislation, RCA has a potential to become a significant enabler of positive change within the construction industry.

Figure 3: ENVIRONMENTAL IMPACT OF CONCRETE RECYCLING , COMING FROM CONSTRUCTION AND DEMOLITION WASTE ( C and DW )

(Source: https://www.semanticscholar.or )

Topic 4: Challenges and Solutions in Using Recycled Concrete in Construction

Khan et al. 2021 included, Recycled concrete (RC) has significant ecological advantages when used in construction projects; however, implementing its use in construction comes with challenges. One of the main concerns is that recycled aggregates do not have a standard quality, which affects the mechanical properties and durable characteristics of RC. This is due to variations in the source materials and methods applied in recycling, which might result in compressive strength, and water absorption lower than those of natural aggregates. This places a great constraint on the utilization of RC in structures to be used for load bearing structures. Scientists pointed out, that better pre-treatment stages, for instance, cleaning and finer crushing can reduce these problems by providing a better quality and homogenous aggregate material.

Another major problem is the absence of normal practice and well defined procedures for applying the RC in the construction businesses. This leads to designers and engineers shying away from considering RC as a feasible material to embrace (Amran et al. 2022). The lack of well defined material descriptors, concrete mix proportions and performance criteria raises concerns regarding the structural integrity of RC. Previous studies pointed out that there is a need for improved guidelines to tackle these challenges, while calling for the adoption of RC’s across national and international institutions especially in applicable building codes. Not only would this improve the credibility of the material, but it would also help the material gain broader utilization in construction. Another negative factor preventing the extensive use of RC is the cost factor (Reis et al. 2021). Despite the evaluation where RC is considered a cheap solution, the extra costs encountered while processing, transporting, and ensuring the improved quality of the part can erode the savings incurred on the use of less material. Several researchers stated that going for regional recycling plants and procuring aggregates from nearby sources greatly reduced haulage costs thus reducing acts of carbon impacts in RC.

In addition, RC also experienced difficulties in the pursuit of the appearance of an ordinary concrete. It also has a rough surface and an unattractive color, which may not be suitable for purposes of architectural buildings and usability. Authors suggest adopting a combination of RC with other materials like fly disc ash and silica fume which may improve the aesthetic and mechanical characteristics of the ultimate structure.

Another type of barrier is the cultural resistance where people regard RC as an inferior material. Overcoming this approach also requires information and education campaigns and numerous demonstration projects illustrating the successful use of RC in various constructions. Positive demonstrations of large scale projects that have utilised RC increase the level of credibility among the stakeholders (Purchase et al. 2021). Although RC has numerous environmental benefits, issues like variability in quality, non-uniformity, expense control, and design constraints need to be thoroughly resolved.

Figure 4: Impact of recycled concrete and Brick

(Source: https://www.mdpi.com )

2.3 Theories and model

1. Interfacial Transition Zone (ITZ) Theory

The ITZ theory forms the backbone of the mechanical behavior of recycled aggregate concrete (RAC). This reveals the interfacial transition zone between recycled aggregates, remnants of the mortar and new cement paste that greatly affects the strength and the nature of RAC. This theory applies to the first topic, “Physical and Mechanical Properties of Recycled Concrete” where Researchers focused on the impact of ITZs of the material’s compressive and tensile strength (Zeng, 2020). These zones contain microcracks and porosities and the integration of the nano-materials such as nano-SiO₂ enhances the density of these areas. This is in consonant with the objectives of the study paper since the main study area is to improve the mechanical characteristics of RAC and its applicability to the construction industry and the sustainable construction business.

2. Life Cycle Assessment (LCA) Model

The LCA outlines specific aspects of recycled concrete and its effects on the environment established by measuring aspects like the emission of greenhouse gases, waste minimization and energy inputs (Cantero-Durango et al. 2023). This model is mainly used in the third topic, that is “Environmental impact of recycled concrete in construction”. Studying LCA, authors illustrated application possibilities of RCA for decreasing the volume of garbage in landfills and usage of natural resources. Due to the systematic evaluation of the environmental trade-offs, this model aids in substantiating the sustainability claims, which aligns with the study’s goal of comparing the environmental benefits of RCA usage.

Figure 5: Li-cycle assessment for green building

(Source: https://oneclicklca.com/ )

3. Two-Stage Mixing Approach (TSMA)

The TSMA is a technical model that has been incorporated in improving the distribution of nano-materials in RAC. Scholars explained this approach in terms of enhancing other properties of what was being developed through the utilization of CNTs and nano-SiO₂, comp (Seong-Uk,, 2022). The further mechanical properties include the compressive strength. This model is connected to the first area of the study on how techniques enhance RAC’s performance, and thus encompass the quest to assess structural usability.

Figure 6: Two stage mixing approach

(Source: https://www.researchgate.net )

4. Cement-Treated Granular Materials (CTGMs) Framework

The CTGMs framework discussed in the second topic, Structural Performance and Usability of Recycled Concrete in Construction Projects provide ways of improving RCA load bearing characteristics. This model was analyzed with regard to road construction projects by researchers and its applicability to enhancing the usefulness of RCA in infrastructure was noted. This framework is in line with the focus of the study, which is to deal with the issue of performance fluctuations and improve construction practices.

2.4 Literature gap

Topic 1: Physical and Mechanical Properties of Recycled Concrete

In the course of the discussion, one area that is not sufficiently examined relates to the durability of the concrete made of recycled aggregate that is modified by nano-materials. While Gao et al. (2023) focused on the enhancement of the compressive strength and the properties of the ITZ, the long-term performance of concrete containing nano-materials on durability when subjected to different environmental conditions was not well explored (Tamanna et al. 2020). This gap lessens the credibility of the discussion on the way that RAC works at the practical level. Reducing this knowledge gap through more protracted accelerated aging tests and field trials would have buttressed the advocacy for RAC use in structural projects.

Topic 2: Structural Performance and Usability of RCA

In the discussion, the authors do not provide information about the practical effectiveness of the proposed method in construction projects other than roads, like high-rise buildings or seismic regions. RB visiting the subbase and base mostly, while ignoring the essential structural applications Aboutalebi Esfahani (2018). To fill this gap, case studies that focus on the application of RCA across different construction types will be valuable, thus supporting the study’s goal of assessing RCA’s usefulness in other settings.

Topic 3: Environmental Impact of RCA

However, the current literature does not adequately match the implementation consequences of RCA treatments, whether in terms of pre-soaking or additional energy costs and the use of supplementary cementitious materials (Kadawo et al. 2023). Researchers emphasized on benefits only, assessing the costs and benefits would complement the environmental sustainability point of view. This way the audience would also get a better idea of novelties and possibilities that RCA could offer.

Topic 4: Challenges and Solutions in Using RC

There is no exposition on the policy and regulatory frameworks needed to encourage the use of RCs. Researchers stressed technical and cost aspects while neglecting the government incentives or mandatory recycling policies (Hu et al. 2020). Including such discussions in a bid to address this gap would have offered practical ways of getting through the barriers to adoption.

2.5 Conceptual Framework

Figure 7: Conceptual Framework

(Source: Self-made)

2.6 Conclusion

Through literature review it can be noted that cracked concrete possesses enhanced environmental and structure potential with reference to sustainability objectives. Areas of improvement such as mechanical properties, usability, and ecological advantages emerged as well as drawbacks like variability, cost, and standardization. These findings are relevant to the objectives of the study to finding ways of enhancing ReCA’s consumption in construction. Several concerns have been outlined as areas in need of improvement in the research, such as coping with the gaps regarding long-term durability and compliance regulation.

Chapter 3: Research Methodology

3.1 Introduction

This chapter presents the method of research that has been used for analysing the viability of incorporating recycled concrete in construction works. This work uses secondary research data and experimental techniques within the assessment of structural characteristics, environmental impacts, and economic feasibility of recycled concrete. The methodology is intended to fit the stated research objectives which involve an evaluation of physical characteristics, practicality and environmental impact of the recycled concrete.

This proposed type of RCAs has received a lot of focus in the last few years given the twin issues of resource availability and management in construction projects. The methodology is structured to examine the potential of RCAs through a critical analysis of the available literature, assessment of experimental data and very limited primary testing. Through its reliance on secondary data sources, this study benefits from a more diverse range of data while avoiding the environmental and scheduling issues that come from a substantial amount of laboratory testing. Also, valuable features including the compressive strength, workability, and the environmental performance are integrated in this methodology to give an assessment of the RCA. The ethical issues are also discussed in the chapter and the limitation of the study is presented as well to improve the credibility of the research effort.

3.2 Research Design

The research is mainly descriptive and analytical in nature whereby an attempt has been made to systematically gather, analyse and interpret most of secondary data with a touch of experimentation. The descriptive aspect is aimed at literature review, while the analytical aspect includes assessment of experimental findings from previous research regarding re.utility of concrete.

A combined-approach is adopted in order to develop a transition between theoretical learning and practical implementation (Gao et al., 2020). Numerical findings of studies done previously conducted in laboratories are combined with qualitative findings of case studies and theoretical models including Interfacial Transition Zone (ITZ) Theory and Life Cycle Assessment (LCA) Model.

3.3 Data Collection Methods

Secondary Data Collection

Secondary data forms the core of this research. Data is sourced from:

• Peer-reviewed journal articles (2020 onwards).
• Technical reports from construction and environmental agencies.
• Case studies on the use of recycled concrete in construction projects globally.
• Standards and guidelines from authoritative bodies such as ASTM and BS.

As discussed in the literature, information includes properties of recycled aggregates and Uses of Aggregates in Construction as well as environmental implications of the processes. Data collection process depends on keyword searches of articles in ScienceDirect, Springer, Google Scholar among others.

Collection of secondary data is planned in such a way that would cover the proposed subject in the most effective way possible. Literature search was done using key phrases like ‘recycled concrete aggregates’, ‘compressive strength of RCAs’, ‘workability and durability of concrete using RCA’ and ‘environmental effects of concrete recycling’. Especially, emphasis is made on those publications made in the course of the last five years to ensure quality and current data is used. Further, to complement this, an endeavor was made to present exclusively gathered global examples of concrete recycling either through reported scenarios or via certain significant organizations like the International Union Laboratories and Experts in Construction Material, Systems, and structure (RILEM), etc (Tam et al., 2021). This systematic approach makes sure that the study is grounded on pluralism principles that facilitate a comprehensive evaluation of RCAs in construction.

Primary Data Collection (Limited Scope)

Although the study focuses on the use of secondary data, some primary data collection is deemed necessary to support particular conclusions. Some tests like compressive strength, workability and durability tests may be performed under prescribed conditions following laid down procedures. For these tests:

• Samples are assumed to include recycled aggregates derived from local demolition waste.
• Tests follow ASTM C39 (Compressive Strength) and BS EN 12390 (Durability and Workability).

In the primary data collection, concrete mixes are prepared with varying proportions of recycled aggregates (25%, 50% and 100% replacement of natural aggregates). These mixes are then evaluated for some specific engineering properties, for instance, compressive strength using the Universal testing machine and workability using slump cone test. Extent of resistance of samples to degradation is determined by carrying out accelerated weathering tests that involve freeze-thaw cycling and sulfate evaluation (Zeng et al., 2020). These site-controlled experiments were meant to improve the understanding of structural performance of recycled concrete where there are gaps in secondary data. But they are fairly limited in scope; these tests provide some of the most useful information regarding the specifics that required RCAs in construction of the projects.

3.4 Sampling Strategy

Sampling methods regard data and information collection solely as a subset from the previously conducted research. Key parameters include:

• Sample Selection: Secondary sources of analysis involve assessments with recycled concrete aggregates with replacement proportions of between 25/100.
• Geographical Scope: Sources used are from global locations and the most preferred are Germany, Japan, the USA in as much as advanced countries mostly adopt recycling norms.
• Material Properties: For the secondary data the samples taken are concrete of different water cement ratio and samples of different gradation of aggregates to investigate variation of performance.

3.5 Experimental Procedure

The experimental procedures are intended in order to assess the mechanical and physical properties of the recycled concrete through the application of appropriate test methods. Although these tests are provisional, they provide a framework for analyzing the material’s performance:

• Compressive Strength: Cylindrical specimens of 150 mm diameter and 300 mm height will be prepared to include different proportions of recycled aggregates. Two tests will be performed to the American Society for Testing and Materials (ASTM C39) specifications, and the results will be compared to those of normal concrete.
• Workability: A slump test corresponding to ASTM C143 will be carried out in order to determine the stability of the concrete mixture (Berredjem et al., 2020). The results will show that placing and handling of recycled concrete reduces compared to the conventional building materials.
• Durability: The primary durability tests will be done in the categories of freeze-thaw cycles and sulfate attack. The accelerated testing methods will mimic long time environmental aggressors and check the applicability of recycled concrete in diverse construction areas.

These are still rather tentative experimental methods but they are comparable with industry standards and are admissible alongside secondary data analytical techniques (Kashyap et al., 2022). This will affirm previous research outcomes presented in the literature with regards to the applicability of the recycled concrete in construction.

3.6 Data Analysis

The aspect of data analysis is based on how to get insights on secondary data in the context of the overall research case about the possibility of recycled concrete. Compressive strength, durability characteristics and workability attributes are evaluated in relation to natural concrete standards. Recycling performance of concrete is characterized by analytical modeling that involves statistical and graphical analysis.

For quantitative data, content analysis is done to arrive at themes as enjoined with regards to environmental impact assessments and challenges that plague industries as depicted in case studies and literature (Khan et al., 2021). This effectively combines the assessment of recycled concrete use based on both quantitative and qualitative views of the concept.

3.7 Ethical Considerations

In conduct of the research, the study observes the ethical guidelines to support the authenticity of the study. Secondary sources found in literature review are also cited to prevent cases of plagiarism. The experimental procedures are always developed in such a way that they do not violate any environmental or safety policies thus reducing the impact they have on the environment (Makul, 2021). In the case of hypothetical primary data, ethical standards provide the procedures on how to handle and dispose of the materials and safety measures to be used.

The study also notes that while coding, it should not come with a bias or influenced by anybody else’s opinion in presenting the findings should not be influenced.

3.8 Limitations of Methodology

The research has several drawbacks; one of them is the use of secondary information, which may be outdated or not generalized for regional peculiarities. The scope of primary data collection here is extremely limited and, therefore, very difficult to validate externally. Potential bias may be noted in figures and composition of recycled aggregates that are seen in second studies, this may cause variability that will affect the comparative results obtained.

Also, assumptions created about the environment of the experiment like the quality of the material, could also prove unfavorable for bestowing generalization of the results.

3.9 Conclusion

Chapter two has presented an overview of the research method with emphasis on qualitative research design with an emphasis on secondary data collection. The research combines a descriptive and analytical dimension to assess the characteristics and performance of recycled concrete. Due to the extensive use of secondary data, the research has access to numerous sources of information while not having to focus on achieving environmental and logistical efficiency. Less primary testing adds a practical dimension to the findings reported above. Nonetheless, issues like data fluctuation, assumptions and less geographic representation are definitely an indication that there is need for further research. Nonetheless, the applied methodology creates a proven theoretical approach for evaluation of the perspectives of using recycled concrete in combating crucial environmental and structural issues thus contributing to the overall enhancement of sustainable construction.

Reference list

Journals

• Aboutalebi Esfahani, M., 2020. Evaluating the feasibility, usability, and strength of recycled construction and demolition waste in base and subbase courses. Road Materials and Pavement Design, 21(1), pp.156-178.
• Amran, M., Huang, S.S., Onaizi, A.M., Makul, N., Abdelgader, H.S. and Ozbakkaloglu, T., 2022. Recent trends in ultra-high performance concrete (UHPC): Current status, challenges, and future prospects. Construction and Building Materials, 352, p.129029.
• Aytekin, B. and Mardani-Aghabaglou, A., 2022. Sustainable materials: a review of recycled concrete aggregate utilization as pavement material. Transportation Research Record, 2676(3), pp.468-491.
• Badraddin, A.K., Radzi, A.R., Almutairi, S. and Rahman, R.A., 2022. Critical success factors for concrete recycling in construction projects. Sustainability, 14(5), p.3102.
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