Demolition Waste Research Articles

Characterization of CDW types by NIR spectroscopy: Towards an automatic selection of recycled aggregates

The petrographic and mechanical heterogeneity of construction and demolition waste (CDW) strongly affects the physic-mechanical performance of new concrete and mortar mixes (RAC: recycled aggregate concrete and RAM: recycled aggregate mortar) made with these recycled aggregates (RA). It is thus extremely important to quickly discriminate and sort them in groups of materials with homogeneous petrography, similarly to primary natural raw materials. Eighteen CDW samples, divided in six groups (natural stones, concrete, bricks, perforated bricks, roof tiles and tiles), from the Abruzzo region (central Italy) are analysed by both micro-X-ray fluorescence energy-dispersive spectroscopy (XRF-EDS) and hyperspectral imaging (HSI), in particular in the short wavelength infrared range (SWIR). Every SWIR spectrum is characterized by three regions of absorption at the following wavelength ranges: 1330–1680 (I), 1830–2140 (II) and 2140–2400 nm (III), displaying the lowest, highest and intermediate intensities, respectively. The first and second wavelength regions are linked to O–H and H–O–H motions, whereas the highest wavelength range is linked to atoms bonded to the O–H environment and/or to the carbonate group. According to previous analysis and to the micro-XRF-EDS surface chemistry, the amount of CaCO3 is rich to very rich for concrete and natural stones, intermediate to absent for masonries and absent for tiles. The intensity or area (%) of the absorption component vibrating at about 2345 nm is directly proportional to the amount of CaO (CaCO3 and CO2), and inversely to SiO2 and Al2O3. Therefore, SWIR can rapidly detect and separate CDW as a function of their carbonate to aluminosilicate contents, i.e. concrete and natural stones made with limestone vs masonries and tiles. The attained outcomes are of paramount importance either for routinely screening or in post-disaster circumstances.

Development and assessment of sustainable steel-concrete composite beams with novel demountable shear connections

The design of sustainable steel-concrete composite beams (SSCCBs) with demountable shear connections (DSCs) for deconstructability can improve the problem of construction and demolition waste during these construction activities, and it also strengthens the sustainability of a building by allowing for easy dismantling and the reuse or recycling of structural components at the service load and easy replacing the damaged members to achieve the resilience capacity after earthquake. In this study, the structural configuration and concept design of novel SSCCBs using DSCs were firstly introduced. The nonlinear finite element models (FEMs) using the Abaqus software were validated in terms of the load versus mid-span deflection curves and failure modes of the similar composite beams given by the experimental data. A parametric study was implemented to identify the influence of the following variables: geometric size, strength grade, inclination angle and shape of concrete plug, diameter and strength grade of connected bolt, steel grade and width and grade of slab concrete. It was found that geometric size, grade and smooth shape of concrete plug could optimize the performance level of occupancy while bolt diameter and grade enhanced the reuse behavior at service loads. Additionally, increasing the bolt diameter and steel grade led to an increase by 8–10% in the equivalent ultimate strength and to decrease the ductility of the whole beams obviously. Bolt diameter, steel grade and slab width have quite influences on the stiffness due to increase the interaction degree of these prefabricated components. Based on the theoretical and parametric analysis results, simple design method of ultimate moment capacity for this SSCCBs with DSCs is proposed to facilitate design practice.

Fabrication and Mechanical Evaluation of Eco-Friendly Geopolymeric Mortars Derived from Ignimbrite and Demolition Waste from the Construction Industry in Peru

Ignimbrite rock is a volcanic material located in the Arequipa region (Peru), and for centuries, it has been used as a construction material, giving a characteristic light pastel, white to pink color to the city of Arequipa, with white being the most common. In the present study, the potential use of three types of Arequipa raw materials (ignimbrite rock powder, calcined clay powder, and demolition mortar powder) as the main source of new binders or the manufacture of environmentally friendly mortars, without the addition of ordinary Portland cement (OPC) is discussed. In this work, an in-depth characterization of the materials used was carried out. The proposed fabrication route for geopolymeric materials was considered for the manufacture of binders and mortars using an alkaline solution of NaOH with values between 12 and 18 molar, as a trigger for the geopolymerization process. Geopolymeric mortars were obtained by adding a controlled amount of fine sand to the previously prepared mixture of binder raw material and an alkaline solution. Conventional OPC and geopolymeric mortars manufactured under the same conditions were mechanically evaluated by uniaxial compression tests at a constant compression rate of 0.05 mm/min and under normal conditions of temperature and atmosphere, where the most optimal values were obtained for 15 molar alkaline solutions of ignimbrite without the addition of aggregates, with values of compressive strength of 42 MPa and a modulus elastic of 30 GPa. The results revealed a significant increase in the maximum strength and modulus of elasticity values when the volumetric fractions of OPC are completely replaced with geopolymeric binders in the study conditions of this work, demonstrating the enormous potential of the ignimbrite rock and construction waste studied, as raw material of alternative mortar binders without the addition of OPC. With this work, the ignimbrite rock, of great value in the region and also found in other areas of the Earth’s geography, was characterized and valued, in addition to the calcined clay and demolition mortar of the region.

Taking spontaneous plants as a natural strategy for vegetation restoration in construction and demolition waste landfills: a case study in Suzhou, China.

Construction and demolition waste (CDW) landfills around the city have caused serious damage to the ecological environment and menaced the public health. Restoration of closed CDW landfills is critical to compensate for the degraded ecosystem and ensure safety in further development and utilization. Vegetation restoration is an essential part of the restoration of CDW landfills, in which the use of spontaneous plants is the foundation of the nature-based strategy. In this study, Fenghuangshan CDW landfill in Suzhou, China, was selected as the research site, and the species composition and diversity of the spontaneous plants were analyzed. Moreover, the types of habitats and growth indexes of 8 species with high frequency and 18 species with medium frequency in the CDW landfill were investigated, and a comprehensive evaluation of growth rate and expansion capacity of the 26 species was conducted. The results showed that, herbs were the main type of the spontaneous plants in the CDW landfill. The species and quantities of the spontaneous plants in the CDW landfill were obviously fewer than those in the surrounding areas of the CDW landfill, and the Shannon-Wiener index and Pielou index of the spontaneous plants were lower compared with the surrounding areas of the CDW landfill. Meanwhile, the differences of dominant families and the distribution of origins, life forms and growth types between these two fields were insignificant. The heliophilous and drought tolerance species were widely distributed in the CDW landfill while the shade-tolerant or hygrophilous species were few. The relatively large comprehensive evaluation indexes of Elymus dahuricus, Daucus carota, Sonchus asper, Geranium carolinianum, Rumex acetosa, Metaplexis japonica, Carex breviculmis, Erigeron canadensis, Trigonotis peduncularis, Lamium amplexicaule reflected their high growth rates and strong expansion capacity, demonstrating their great potentiality in the vegetation restoration of CDW landfills as indispensable components of the nature-based solution.

Environmental feasibility and implications in using recycled construction and demolition waste aggregates in road construction based on leaching and life cycle assessment – A state-of-the-art review

Due to rapid population growth and urbanization, construction activities have increased worldwide resulting in generation of enormous volume of construction and demolition (C&D) waste. On one hand, C&D waste is generated during the construction, destruction, and rehabilitation of existing structures. While on the other, the transportation sector consumes large volumes of aggregates for pavement construction and maintenance. The extraction of finite natural aggregates causes potential damage to the environment. Recycled C&D waste, once converted into recycled aggregates, has the potential to be utilized in pavement layers due to its sound quality and composition; also resulting in lowering the landfill loads. This review article critically summarizes the environmental risks regarding chemical composition and leaching behavior of C&D wastes in pavements. Additionally, this review evaluates the environmental impacts of C&D waste aggregate production and application in pavements using life cycle assessment (LCA). Overall, the aim of this study is to investigate the environmental impacts and benefits of C&D waste to enable highway administrations to adopt and promote the use of C&D waste in development of sustainable road infrastructure. In this way, the review articleattemptsto promotea new era of sustainable road construction and achieve net zero waste goal.

Optimizing City-Scale Demolition Waste Supply Chain Under Different Carbon Policies.

In order to establish a green, low-carbon circular development economic system, imperative goals include achieving carbon peaking and carbon neutrality. This research delves into the resource utilization of city-scale demolition waste (C&DW), aligning with environmental protection needs and sustainable development principles. The paper introduces a unique closed-loop supply chain (CLSC) model tailored for C&DW and employs a distinctive mixed integer nonlinear programming (MINLP) model for optimization. Guangzhou serves as a case study for thorough analysis, verification, and practical application of the proposed model, especially under diverse scenarios of carbon price (CP) and carbon trading (CT) policies. The key conclusions drawn from this study include the following: (1) The cost of carbon emissions is intricately influenced by both carbon emissions and carbon price, with the latter effectively regulating the carbon emissions during C&DW recycling. (2) The implementation of a CT policy, with a fixed carbon price, contributes to a further reduction in the cost of C&DW recycling treatment. (3) Under equivalent conditions, the CT policy demonstrates the potential to decrease costs and enhance the economic benefits within the building environmental protection product market. The research outcomes not only contribute to the advancement of management theory in the C&DW recycling supply chain (SC) but also provide a robust theoretical foundation for governmental initiatives aimed at introducing effective C&DW recycling management policies.

Temporal analysis of settlement areas and city footprints on construction and demolition waste quantification using Landsat satellite imagery

Municipal solid waste management has seen a surge in the use of satellite imagery in decision-making processes, yet its application to analyze quantitative variations in construction and demolition (C&D) waste remains under-investigated. This study employs satellite imagery and multivariate analysis to comprehensively assess and predict C&D waste generation in four diverse urban jurisdictions of Canada (Regina) and the USA (Seattle, Buffalo, and Philadelphia). Factors such as settlement area expansion, economic activities, and population growth significantly influence C&D waste rates. Stepwise multivariate regression models tailored to different city types, such as moderately populated (Group 1) and highly populated (Group 2), showcase acceptable predictive capabilities. For moderately populated cities, settlement area, average humidity, and GDP are identified as key predictors, while for highly populated cities, settlement area, unemployment rate, and building permit value prove effective indicators. These models, characterized by R² values from 0.70 to 0.94, provide tailored insights for distinct demographic conditions, aiding waste management planning. This research underscores the importance of satellite imagery and multivariate analysis in understanding C&D waste dynamics and empowers policymakers and waste management agencies with evidence-based strategies for effective waste management in urban centers.

Enhancing a circular economy for construction and demolition waste management in China: A stakeholder engagement and key strategy approach

China's construction and demolition waste has been substantially increasing due to the country's urbanization. However, since the recycling rate of construction and demolition waste is still much lower in China compared to most developed countries, its construction industry still relies heavily on natural resource consumption and is very much a linear economy. Although a circular economy for construction and demolition waste management has been promoted by the government in recent years, the transition from open-ended to close-looped circularity for construction and demolition waste management strategies have not been fully investigated. This study therefore identifies stakeholder engagement and closed-loop key strategies as part of a circular economy for construction and demolition waste management in China. Integrated approaches are used to achieve the aim of this study including literature review, semi-structured interview, questionnaire survey, and causal loop diagram development. The stakeholder engagement and key strategies were identified through literature review, semi-structured interviews, questionnaire survey, and statistical analysis. A causal loop diagram was then developed to demonstrate the interconnection and causal effect between stakeholders and key strategies. The findings reveal that stakeholder engagement and key strategies are highly interrelated for achieving closed-loop construction and demolition waste management. Government ranks as the most important stakeholder engagement, and improving secondary material quality and value is the most important key strategies. This study provides insights for practitioners and academics alike to help understand the interrelationship between stakeholder engagement and key strategies as part of a circular economy for construction and demolition waste management in China.

Pore Structure, Hardened Performance and Sandwich Wallboard Application of Construction and Demolition Waste Residue Soil Recycled Foamed Concrete

Construction and demolition waste residue soil (CDWRS) recycled foamed concretes were prepared by introducing the original CDWRS into modified binders. Pore structure, hardened performance, and sandwich wallboard application were also investigated. The results indicated that 51 kg/m3 of water glass and 7.5 kg/m3 of gypsum could significantly increase the strength and generate a slight influence on the thermal insulation performance of CDWRS recycled foamed concrete. The largest enhancing rate of 28-day compressive strength at a density of 600 kg/m3 could reach 205.5%. Foamed concrete with 1126 kg/m3 of CDWRS, modified with water glass and gypsum, showed a low thermal conductivity of 0.11 W/(m·K) and a dry density of 626 kg/m3. In total, 988 kg/m3 of CDWRS in foamed concrete led to a compressive strength of 7.76 MPa, a thermal conductivity of 0.14 W/(m·K), and a dry density of 948 kg/m3. Utilization of the foamed concrete in the sandwich structure could fabricate energy-saving wallboards with a minimum heat transfer coefficient of 0.75 W/(m2·K) and a relatively high compressive strength of 16.5 MPa, providing great confidence of CDWRS consumption in the building energy-saving field.

Investigating the Determinants of Construction Stakeholders’ Intention to Use Construction and Demolition Waste Recycling Products Based on the S-O-R Model in China

In China, the annual generation of construction and demolition waste (CDW) has been steadily increasing, accompanied by a generally low recycling rate. To promote sustainable development, there is an urgent need to enhance the recycling of CDW. This paper aims to investigate the determinants of construction stakeholders’ intention to use CDW recycling products in China. The stimulus–organism–response (S-O-R) model, integrating the technological–organizational–environmental (TOE) framework, personal perceptions, personal traits, and the intention to use, was chosen as our theoretical model. Through an analysis of 272 valid questionnaires, the partial least squares structural equation modeling (PLS-SEM) was utilized to evaluate the model and test the proposed hypotheses. The results indicated that personal traits are the most influential factor shaping construction stakeholders’ intention to use, followed by personal perceptions, while external stimuli exert no direct significant impact on the intention to use. Nevertheless, personal traits and personal perceptions play a significant mediating role in the relationship between external stimuli and the intention to use, forming a noteworthy serial chain mediation. The research findings imply that in China, bolstering personal traits plays a critical role in guiding and promoting the intention to use CDW recycling products.

Stakeholder interactions of government intervention in construction and demolition waste recycling market: A game theory approach

To acquire an in-depth understanding on how government intervention affects C&DW recycling market, this study develops four game models consisting of three main categories of stakeholders, e.g., the government, contractors, and C&DW receivers (recycling enterprises and landfills) to reveal stakeholder interactions of government intervention. Taking China's C&DW recycling market as an example, four different scenarios are established to examine and compare the effects of government intervention policies on C&DW recycling, illegal dumping, and stakeholder profits. Finally, numerical simulations are performed to gain further insights into the impact of government intervention on stakeholders' behaviors with a case study from Shenzhen, China. Results indicate: (1) government intervention policies can always lead to an increased amount of C&DW recycled and a reduced amount of C&DW illegally dumped compared to no any measure; (2) government subsidy can improve the market competitiveness of recycling enterprises and weaken the competitiveness of landfills. Both subsidy-only and subsidy-plus-penalty policies help reduce economic burden on contractors compared to no interventions, but penalty policy increases contractors' expenditures. Finally, penalty policy can significantly reduce the amount of illegally dumped C&DW, while subsidy policy can significantly increase the amount of recycled C&DW. This study provides valuable theoretical support and practical guidance for decision-making of governments in developing economies to develop C&DW recycling by formulating targeted intervention policies.

Sustainable urban development: Evaluating the potential of mineral-based construction and demolition waste recycling in emerging economies

Widespread illegal disposal of surging construction and demolition waste (CDW) is a prominent threat to recycling, leading to resource wastage and environmental issues. The lack of data is a major barrier to designing an effective waste management system in emerging economies. Employing a mixed-method approach, a cross-sectional case study was conducted on an Indian city to assess the existing system and investigate the root causes of low recycling rates and limited demand for recycled materials. The study finds that (a) illegal disposal is prevalent due to the "end-of-pipe" approach of the waste management system, (b) policy enforcement on waste generators is weak, (c) low-rise residential buildings are the major contributor of waste, (d) low demand for recycled material is due to lack of awareness, marketing, incentives, and high costs, (e) transportation costs are 50 % higher than the recycled material cost, and (f) lack of segregation leading to the production of low-value materials. All these factors make recycling unattractive and the circular economy (CE) unfeasible. Stakeholder awareness, a centralized trading platform, and integrated waste management systems are essential to promote recycling and advance SDGs 9, 11, and 12, focusing on industry, sustainable cities, and responsible consumption and production.

Structural Behaviour of Reinforced Concrete Beams Made of Selected Waste Glass and Ceramic Tiles

Worldwide, construction and demolition wastes contribute the most wastes. Hence, environmental concerns have been raised, and more investigations have been recommended for recycling potential. Glass and Ceramic wastes are currently disposed of in landfills. This paper aims to study the structural behaviour of non-conventional concrete made of waste glass and ceramic tiles. A comparison is conducted between the normal and non-conventional concrete beams. The non-conventional concrete is made by replacing normal sand and gravel at 25% and 50% percentages. Both glass and ceramic tiles are used separately and blended in three different types (A, B, & C) of concretes. The laboratory experiments are verified with a Finite Element model for the three reinforced concrete types using ANSYS software. The results of conducted comparison shown that the non-conventional reinforced concretes have acceptable consistent with the normal reinforced concrete, and the reuse of glass and ceramic waste is technically feasible.

Water Absorption of Foamed Concrete using Recycled Aggregate Derived from Construction and Demolition Waste

Water Absorption of Foamed Concrete using Recycled Aggregate Derived from Construction and Demolition Waste

Effect of recycled aggregate treatment methods by pristine graphene on mechanical and durability properties of concrete

Using recycled concrete aggregates (RCAs) in concrete is a promising approach to minimise the environmental impacts associated with construction and demolition waste while simultaneously enhancing the sustainability of concrete. Improving the quality of RCAs is crucial for promoting confidence among materials suppliers and systematic utilisation of RCAs in construction. Pristine graphene (PG) suspensions (0.1% and 0.2% concentrations in water) were investigated for improving the properties of RCAs and thereby improving the mechanical and durability properties of concretes made with 100% RCAs as coarse aggregates. Two PG treatment methods were used – spraying and soaking. Nano-silica (NS) suspensions of the same concentrations were also used for comparison. Tests for axial compressive, splitting tensile and flexural strengths were performed; water absorption and drying shrinkage were also assessed. Microanalysis was conducted using scanning electron microscopy and micro computed tomography. PG was found to be more effective than NS for increasing strength properties and reducing water absorption and drying shrinkage of concrete due to its lower porosity. For a given nanomaterial concentration and type, concretes made with soaked RCA exhibited higher strengths and lower water absorption and drying shrinkage than concretes with sprayed RCA. The concretes made with soaked RCA also had lower porosity and fewer microcracks. The results are promising and indicate that treating RCAs reduces their water absorption, thereby improving concrete performance.

Water Absorption of Foamed Concrete using Recycled Aggregate Derived from Construction and Demolition Waste

Water Absorption of Foamed Concrete using Recycled Aggregate Derived from Construction and Demolition Waste

Integrative approach for optimizing construction and demolition waste management practices in developing countries

Integrative approach for optimizing construction and demolition waste management practices in developing countries

Use of recycled concrete and rice husk ash for concrete: A review

The rapid development of populations and the demand in the consumption of concrete is generating the need to produce larger quantities of cement, which brings with it negative effects for the environment. Approximately 0.87 kg of CO2 is produced by the manufacture of cement; In addition, the use of aggregates is generating great concern in the construction industry, due to the costs and the restriction of these. Similarly, the accumulation of construction and demolition waste (RCA) and rice husk ash (RHA) contribute to pollution. Therefore, the objective of this manuscript is to review the literature on the use of RCA and RHA for the elaboration of concrete. For this, indexed articles were used, between the years 2017-2021. The results showed that when 8% RHA is added, the concrete reaches a compressive strength of 70 MPa; as well as, the flexural strength of concrete by adding 50% RCA + 1.50% basalt microfibers was increased by 29.44%. On the other hand, when RHA is added by 15% it reaches a compressive strength of 48.8 MPa; in turn, the mechanical performance at bending with 10% seashell by fine aggregate and 20% RHA by cement, reached a resistance of 65 MPa. Concluding, that the behavior of concrete undoubtedly depends on the proportions of either RCA or RHA; however, the percentages must be no more than 8% and 15% respectively.

Köpük Beton Üretiminde İnşaat Yıkıntı Atığı İnce Agregası Kullanımı ve Optimum Su/Çimento Oranının Belirlenmesi

İnşaat sektöründe hammadde temini doğal kaynaklarımız hızlı azalmasına veya tahrip edilmesine neden olmaktadır. Doğal kaynakların azalmasını veya tahrip edilmesini azaltmak için inşaat yıkıntı atıklarının geri kazanılması, hammaddeye ihtiyacını ve aynı zamanda çevresel kirliliğini de azaltılacaktır. Bu çalışmada inşaat yıkıntı atığı ince (kum) agrega ile köpük beton üretile bilirliği araştırılmıştır. Karışımlarda agrega olarak 4 mm elekten geçen inşaat yıkıntı atığı kullanılarak 5 farklı su/çimento oranı ile köpük beton üretilmiştir. Üretilen köpük beton numunelerinin birim hacim ağırlıkları, basınç dayanımları, su emme oranı, ultra ses geçiş hızı ve ısıl iletkenlik katsayıları gibi özellikleri incelenmiştir. Bu özeliklerden en uygun olanlar S/Ç oranı 0,45 olan karışım tasarımı vermiştir.

Sustainable geopolymers from polyethylene terephthalate waste and industrial by-products: a comprehensive characterisation and performance predictions

Several researchers have recently worked to create sustainable building materials. One of the fundamental prerequisites for sustainable construction methods and environmental impact assessments is the use of green building materials and manufacturing processes. In this research study, geopolymer bricks were developed using polyethylene terephthalate waste and different industrial by-products (rice husk ash, ground granulated blast furnace slag, red mud, construction, and demolition waste) and investigated their performances. The polyethylene terephthalate waste was used as a replacement for sand filler in the geopolymer brick up to 100%. Key findings include a workability decrease of 14.75% and a compressive strength reduction of up to 75% with 100% plastic waste replacement, attributed to increased voids and weak geopolymer matrix interaction. Dry density consistently decreases, and water absorption rises to 13.73% with full sand replacement, indicating a porous structure. Impact resistance improves with plastic waste inclusion, enhancing ductility and thermal conductivity by 57% at full replacement. Microstructural analyses reveal correlations between physical–mechanical properties and changes in porosity, microcracks, and bond strength. Machine learning, especially linear regression, proves effective for strength parameter prediction (up to 100% efficacy, R-square of 0.998). The promising results obtained could offer a substantial environmentally friendly solution to the building and construction industry in line with Circular Economy principles.