Keywords

1 Introduction

Construction waste (CW) is considered as a significant challenge in the building sector. Skoyles [1] defined CW as material waste that arises due to construction activities. Other sources define construction waste as the produced debris or discarded materials that occur during various construction activities and phases [2, 3]. Either way, construction waste is a major contributor to waste generation, harming the planet and impacting society and the economy [4, 5]. Consequently, it is widely acknowledged that addressing construction waste is a top priority issue.

Statistically, more than 32% of municipal waste is generated by construction activities worldwide [6]. In the EU, around 35% of the total waste is a construction source [7]. Similarly, CW represents 30–40% of the total municipal solid waste in the US, UK, and Australia, making the construction sector a primary source of materials dumping and landfilling [8]. In other regions, such as Jordan and Malaysia, CW amounts to more than 30 million tons and 9 million tons of waste on an annual basis, respectively [5].

Due to population growth and the excessive demand for construction and building projects worldwide [9], CW is anticipated to increase dramatically [6], among other reasons, as discussed in Loizou et al. [10], waste creation is inevitable in infrastructure projects with the current technology and construction methods. However, it can be mitigated through efficient management strategies. For instance, repurposing construction waste could improve environmental preservation and economic opportunities.

Waste minimisation is vital for sustainability, and focusing on waste sources is a critical step to reduce the environmental impact [8]. Several researchers investigated minimisation strategies and recommended multiple actions across various project stages that could be quantified throughout lifecycle assessments. Hence, this study aims to scrutinise the multifaceted causes of construction waste, and proposed strategies to mitigate it in the design, procurement, and construction phases, as informed by the existing literature. Subsequently, the causes of waste are associated with potential sustainability measures that could significantly contribute to its mitigation. Figure 1 shows the research process followed in this study.

Fig. 1.
figure 1

Research process based on existing literature.

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2 Construction Waste Generation

2.1 Causes of Construction Waste

The waste type and quantity in the construction sector are highly influenced by construction size, type, and technology used [11] while it is generated in different amounts during each project stage [12]. Researchers have found that CW multiplies due to design issues and errors, improper scheduling, reworks, lack of skilled labours, poor project management, materials storage and handling, and ill management of waste [5, 12,13,14,15]. Table 1 summarises the most common categorisations of construction waste.

Table 1. Summary of the common construction waste factors in the literature.
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It has been noted that the causes of construction waste generation are categorised differently by researchers. For instance, Al-Rifai and Amoudi [13] investigated the causes in the Jordanian’s building sector and classified waste factors in terms of their contribution to total amounts: high, medium, low, and very low. Obaid et al. [11] grouped construction waste into physical or non-physical, time and cost. Other researchers classified construction waste based on the construction stages [16]. For instance, they investigated waste minimisation in the design stage, procurement, and construction and classify waste accordingly [8]. Other studies categorised factors based on their origins; for example, Luangcharoenrat et al. [15] identified 28 factors contributing to construction waste and categorised them into four groups ranked from the most significant to the least significant: design and documentation, human-related, construction planning and methods, and materials and procurements. In addition, handling, site condition, and external factors are also identified as categories for construction wastes by Nagapan et al. [3].

CW cause factors are influenced by construction type and building techniques that also vary from region to region [15]. For example, a study by Al-Rifai and Amoudi [13] in Jordan found that construction waste is mainly driven by poor management and issues with the workforce. Instead, Nagapan et al. [17] identify poor site management and supervision as Malaysia's most significant construction waste factors. Hence, there is not yet a uniform categorisation criterion, which causes substantial delays in tracing the waste source and implementing the relevant strategies for waste reduction.

3 Construction Waste Minimisation

3.1 Design Stage

Engineering practitioners, academics, and scientists all emphasise the role of waste-efficient design, eco-design, and design for deconstruction to mitigate waste generation [18]. Ajayi et al. [19] place enhanced prefabrication techniques, pre-assembled components, and modular design as the core of waste reduction strategies in the design stage. Osmani [20] added to this by reporting on the current practices in the UK to minimise waste, which includes the standardisation of dimensions for steel and concrete profiles, prefabricated ancillary items, and design for disassembly. Olanrewaju and Ogunmakinde [21] further investigated strategies to reduce CW during the design stage and referred to Nigerian architects’ most common strategies, including standard materials and products. Separate studies explore the effects of implementing BIM in construction projects and found that this facilitates sustainable construction and helps minimise waste by enabling design adaptability, which allows for more efficient planning and easier modifications, for example, Alasmari et al. [22]. We close this point by citing Laovisutthichai et al. [23], who state that the CW and construction cost could be reduced without compromising the design if we adopt the design for construction and waste minimisation (DfCWM) modern guidelines such as Wrap [24].

3.2 Procurement

Any improvement to design and management could not be separate from procurement. The main strategies suggested by the authors are on-time delivery, proper storage, purchasing products with little or no packaging, and over-ordering prevention [25]. Ajayi et al. [26] emphasised the importance of considering CW in procurement and identifying delivery management, supplier commitment to reduce waste, waste-efficient bill of quantity, and low waste purchase management as the main features in waste reduction during procurement. Furthermore, Nagapan et al. [27] identify ordering errors, shipping mistakes, and inaccurate quantity calculations as the causes of construction waste in the procurement stage. Thus, new reduction strategies could be developed to further integrate procurement into the production process.

3.3 Construction

Construction techniques can be improved through enhanced technologies, including using green materials, implementing relevant legislation, and implementing behavioural-based methods to increase worker efficiency [28, 29]. Additional on-site minimisation strategies are related to waste collection and reuse, although those are labelled as reactive strategies [30]. Waste source minimisation measures shall be considered in the construction phase under a rational structure, for example, through groups defined as field planning & management, and materials management [25, 26]. Hence, both the generated waste and its sources could be the focus to minimise sending materials to the landfill and maximise the benefits of the resource. Table 2 summarises waste minimisation practices in the current construction landscape.

Table 2. Summary of the common construction sustainability practices in the literature.
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4 Proposed Waste Causes- Sustainability Practices Matrix

The construction industry faces significant challenges in managing and reducing waste, raising concern for its environmental, economic, and societal implications. To address this, various sustainable practices have been proposed, targeting different waste causes in construction projects. Table 3 presents a linkage between common waste causes and sustainable practices, providing an insightful idea for enhancing sustainability in construction activities.

Table 3. Matrix linking sustainability practices to waste causes in construction projects.
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5 Conclusions and Future Work

The paper discusses the main issues related to construction waste (CW) and provides insight into the causes of construction waste. It goes on to address sustainability aspects and waste minimisation practices in construction projects.

The causes of waste have been previously investigated and categorised into defective planning, human errors, and design mistakes, including improper handling. These causes vary in their impacts based on the project's size, type, and technology used.

Strategies across the construction phases (design, procurement, and construction) are proposed from the literature to mitigate the risks associated with construction waste. Waste-efficient design, Design for Disassembly (DfD), and standard design practices minimise waste from the design phase. During procurement, key practices include avoiding over-ordering, reducing packaging, and ensuring supplier commitment. Meanwhile, in the construction phase, effective measures include on-site waste management and material management to mitigate construction waste.

The paper contributes to the field by identifying the leading causes of construction waste (CW) and underscores the importance of integrating sustainability practices into the main construction phases: design, procurement, and construction. Furthermore, this study contributes by constructing a matrix that links the identified causes of construction waste with sustainability practices, offering a comprehensive overview of effective ways to reduce construction waste. However, the study is limited to the existing literature, and empirical studies are needed to highlight the strategies’ significance and impact on CW reduction.

Future studies should focus on quantifying the economic benefits of waste management, assessing the long-term social and environmental impacts, and validating the matrix through case studies to clearly outline the relationship between waste causation and sustainability practices, thereby ensuring a comprehensive understanding of the subject.