Demolition Waste Research Articles

Assessment of the mechanical and physical characteristics of PET bricks with different aggregates

Construction and demolition waste, along with discarded PET plastic bottles, have evolved into a widespread global resource. However, their current disposal in landfills poses a significant environmental pollution challenge. This research is centered on evaluating the performance of cement mortar composed by larger PET particles in conjunction with sand, construction and demolition waste, and lightweight expanded polystyrene aggregates. The primary objective of this study is to formulate a blend suitable for non-structural elements that can be easily manufactured for social housing construction. This modified blend extends upon the original certified mixture employed at CEVE for brick production, which encompasses cement and 3 mm-long PET particles. The experimental analysis revealed that blend containing 8 mm-long PET particles, in combination with fine aggregates of construction and demolition waste, attained a required mechanical strength of 2 MPa, while preserving the bulk density and hydric properties of the initial PET bricks developed at CEVE in Argentina.

A framework for evaluation of construction and demolition waste management alternatives using MCDA techniques in the context of Dhaka City

Landfilling and dumping are the common strategies to manage generated construction and demolition waste (C&DW) in Dhaka City. These strategies of C&DW management (C&DWM) affect the environment adversely and fill the old landfill sites quickly. Besides, there isn’t any framework to manage C&DWs effectively. This study introduces a Multi-criteria Decision Analysis (MCDA)-based C&DWM framework for Dhaka City by incorporating the expanded Waste Management Hierarchy (E-WMH). The E-WMH principles are considered as the C&DWM alternatives. Through a comprehensive literature review, the criteria are determined and grouped into social, economic, environmental, and technical criteria to achieve sustainability and effectiveness. To construct the initial decision matrix, the ordinal data (i.e. rating) is collected through interviews with the subject-matter experts of Dhaka City. Also, the ranking system method is used to determine the weight of the criteria. Finally, the ELECTRE I and ELECTRE II MCDA methods are employed to rank the alternatives. Results show that reuse and recovery are suitable strategies for managing C&DWs in Dhaka city. Future studies may consider the hybridization of MCDA tools, quantitative data to form the initial decision matrix, and other mathematical models to weigh the criteria so that the performance of the framework can be enhanced.

Mechanical and Durability Characterization of Hybrid Recycled Aggregate Concrete.

The recycling of construction and demolition waste (CDW) for the extraction of recycled concrete aggregates (RCAs) to be used to produce recycled aggregate concrete (RAC) is widely acknowledged internationally. However, CDW not only contains concrete debris but may also contain burnt clay bricks. The recycling of such CDW without the segregation of different components would result in recycled aggregates having different proportions of concrete and brick aggregates. The utilization of these aggregates in concrete requires a detailed investigation of their mechanical and durability properties. In this regard, the present study focused on investigating the mechanical and durability properties of hybrid recycled aggregate concrete (HRAC) made by the 100% replacing of natural aggregates with recycled brick (RBAs) and RCA in hybrid form. The partial replacement of cement with fly ash was also considered to reduce the corban footprint of concrete. An extensive experimental program was designed and carried out in two phases. In the first phase, a total of 48 concrete mixes containing coarse RBA and RCA in mono and hybrid forms were prepared and tested for their compressive strength. The test results indicated that the compressive strength of HRAC is greatly affected by the proportion of coarse RBA and RCA. In the second phase, based on the results of the first phase, eight concrete mixes with the most critical proportions of RBA and RCA in hybrid form were selected to evaluate their mechanical and durability performance. In addition, four mixes with natural aggregates were also prepared for comparison purposes. To evaluate the mechanical properties of the concrete mixes, compressive strength and modulus of rupture (MOR) tests were performed, while for the evaluation of durability properties, water absorption and behavior after exposure to aggressive conditions of acidic and brine solutions were studied. The results revealed that a 20% replacement of cement with fly ash resulted in acceptable mechanical and durability properties of HRAC intended to be used for making concrete bricks or pavers.

Feasibility of using building-related construction and demolition waste-derived geopolymer for subgrade soil stabilization

A high-value utilization approach is essential to improve the utilization rate of building-related construction and demolition waste (brCDW). This study developed a novel approach by synthesizing a brCDW-derived geopolymer to stabilize high liquid limit subgrade soil. The unconfined compressive strength (UCS) test, shear strength test, resilient modulus test, and permanent strain test were conducted to investigate the effects of brCDW-derived geopolymer dosage, curing time, stress state, and moisture condition on the engineering properties of geopolymer stabilized soil. These test results demonstrated that increasing the geopolymer dosage effectively improved the UCS, shear strength and resilient modulus of stabilized soil and reduced the permanent strain of stabilized soil. The 8% brCDW-derived geopolymer provided adequate UCS, shear strength, resilient modulus, and resistance to permanent strain for stabilized soil, which showed the most economical improvement. Mechanistic-empirical models were employed to accurately estimate the stress-dependent resilient modulus and permanent strain of geopolymer stabilized soil at any given stress state. The Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) test were performed to investigate the strengthening mechanism of brCDW-derived geopolymer stabilization of subgrade soil. The SEM test results indicated that the porosity of stabilized soil was significantly decreased when the geopolymer dosage increased to 8%. The EDS test results demonstrated that the predominant gel types generated from the geopolymer stabilization might be Calcium–Aluminum-Silicate-Hydrate (C-A-S-H), Calcium-Silicate-Hydrate (C–S–H), and Calcium-Aluminate-Hydrate (C-A-H) gels. There was also a small amount of Sodium-Alumino-Silicate-Hydrate (N-A-S-H) gel detected in the geopolymer stabilized soil. Finally, the sustainability of brCDW-derived geopolymer stabilization approach was assessed in terms of material production cost, carbon dioxide emission, and energy consumption. The brCDW-derived geopolymer was proven as a sustainable stabilizer for subgrade soil.

Effect of temperature and additives on recycled waterborne coating preparation and performance for construction and demolition waste reutilization

Effect of temperature and additives on recycled waterborne coating preparation and performance for construction and demolition waste reutilization

Consumer purchase intention for extrinsic and intrinsic cues of construction and demolition waste recycled products

PurposeThe preferences and adoption of recycled materials by consumers are subject to a variety of factors, such as enablers and barriers. Despite this, there exists a paucity of research concerning stakeholders' perceived value and real purchase decision towards recycled products. Consequently, this research study aims to fill this gap by investigating stakeholders' perceived value of recycled products derived from construction and demolition (C&D) waste and its effect on purchase decisions.Design/methodology/approachResearch data were collected from 219 valid questionnaires completed by Chinese stakeholders. Structural equation modeling (SEM) was then employed to test eight hypotheses.FindingsThe results show intrinsic cue (materials) and extrinsic cue (brand) influence the stakeholders’ judgment on C&D waste recycled products’ value and then their purchase intention. However, cues such as quality, word-of-mouth, price, policy and advertised have not play a significant role in practice.Originality/valueThis research study verified the significance of brand and material cues on decision making for purchasing C&D waste recycled products, providing new insights to policy making to enhance the uptake of C&D waste recycled products in construction industry.

Environmental and Economic Viability of Using Concrete Block Wastes from a Concrete Production Plant as Recycled Coarse Aggregates.

The construction sector must incorporate the circular economy to improve sustainability and efficiency. The use of recycled aggregates (RAs) as a substitute for natural aggregates (NAs) is currently being investigated and is expected to yield considerable benefits in the future. The objective of this research is to evaluate the environmental and economic benefits of using recycled coarse aggregates (RCAs) in different 1 m3 samples of concrete, substituting the natural coarse aggregate (NCAs) with RCAs in different percentages. RCAs generally come from the treatment of construction and demolition wastes (CDWs). However, in this research, the RCAs are the concrete block wastes (CBWs) generated by a concrete production plant. Among the most notable results is that compared to concrete with no RCAs, using alternatives in which RCAs have replaced 50% of the NCAs leads to an average decrease in impact category statistics of -3.30%. In contrast to the existing literature on the subject, the process of producing RCAs generated efficiency improvements in categories such as abiotic depletion of fossil fuels (-58.72%) and global warming potential (-85.13%). This is because the transport process, a key factor in determining the viability of using RAs instead of NAs, was eliminated. In economic terms, there is a slight decrease in the financial cost of producing 1 m3 of concrete as the quantity of RCAs increases. The maximum decrease was 0.23€/m3 in the samples studied. Combining both the environmental and economic aspects resulted in a reduction factor of 0.420 g of CO2/€cent, which means fewer CO2 emissions per unit cost when using RCAs. In conclusion, these results are intended to further knowledge in the field of using RAs instead of NAs in order to help the sector achieve sustainability and find an alternative use for a particular type of business waste.

Investigation of Rates of Demolition Waste Generated in Decoration and Renovation Projects: An Empirical Study

There is an increase in decoration and renovation activities in the construction industry, and waste generation rates (WGRs) play a crucial role in guiding the management of demolition waste in decoration and renovation projects (DWDRPs). However, there has been little systematic research on this type of waste. Based on site surveys and a document review of 26 projects, this study offers insights into DWDRP wastes, from their initial generation to their final disposal. The results revealed that the WGRs for DWDRPs ranged from 30.96 kg/m2 to 629.96 kg/m2 and that the key components of DWDRPs included mortar, concrete, timber, tile, and metal; these five types of waste contributed 75.02% of the total waste. Although these findings deviate slightly from those of previous studies, these variations are attributed to diverse waste management practices, awareness levels, and employed construction technologies. Despite its importance, in China, the management of DWDRPs faces challenges, such as limited public awareness, inadequate collection and sorting guidance, and insufficient legislation. To counter these issues, we recommend a set of strategies, including stringent regulations, enhanced supervision, government incentives, improved collection and sorting methods, and the adoption of innovative technologies. This study not only sheds light on the specific challenges in decoration and demolition waste management in rapidly urbanizing areas but also proposes a comprehensive approach for improving waste management practices.

Valorization of spent Zn-C battery and construction and demolition waste (CDW): Fabrication and characterization of geopolymer composites for radiation shielding applications

There is a serious threat of pollution due to the high waste of energy and materials worldwide that needs to be decreased. One way is to reduce waste or use them in secondary processes. New eco-friendly geopolymer binders were fabricated using metakaolin, CDW, and battery waste (BW) powders as starting materials and a mixture of potassium silicate and sodium hydroxide as activation solutions. 5 formulations with BW powder replacements ranging from 5 to 40 wt% were prepared and subjected to heat curing at 80 °C for 24 h. The effect of Zn-C battery waste content on the phase composition, densification, microstructure, mechanical, and gamma shielding properties of the obtained geopolymer composites was investigated. The results revealed that incorporating battery waste reduced the density and mechanical strength of the geopolymer composites. Additionally, microstructural analysis indicated that synthesized geopolymers consisted of unreacted CDW and BW particles embedded in a geopolymer matrix with a low degree of compactness. The effect of BW replacement on the shielding capacity was also evaluated experimentally and theoretically. The gamma transmission experiments proved that the addition of BW caused a reduction in the radiation shielding ability of the composites when they were exposed to 137Cs and 60Co gamma-ray sources. Finally, the variation of the main attenuation parameters (MAC, HVL, EBF, and EABF) with photon energy was also obtained theoretically. The outcomes of this investigation can provide a basis for the design of new CDW-based geopolymers for radiation shielding applications in the context of a circular economy.

Performance evaluation of recycled concrete aggregates with geosynthetics as an alternative subbase course material in pavement construction

This study investigates the feasibility of using recycled concrete aggregates (RCA) as subbase materials in roads through laboratory experiments. Various physical tests were conducted on the soil subgrade and RCA subbase, followed by cyclic plate load tests to assess the impact of geosynthetic reinforcement on the bearing capacity of RCA materials. The ultimate bearing capacities of different RCA configurations ranged from 186 to 480 kPa, similar to previous studies on natural and recycled aggregates. The geocell-reinforced section exhibited excellent performance, with a measured ultimate bearing capacity of 480 kPa. The Geocell-Geogrid and Geocell-Geotextile sections showed the highest bearing capacity ratios at 2.58 each, indicating superior performance. Reinforced RCA infills demonstrated improved settlement values under repeated loading, with the geocell-geogrid section effectively reducing permanent settlement. The study concludes that RCA can be a substitute for natural aggregates in road subbase materials, mitigating the environmental impact of construction and demolition waste.

A systems-focused assessment of policies for circular economy in construction demolition waste management in the Aysén region of Chile

This study pairs a recently developed regulatory framework for Chile with a regional case study in Aysén to highlight systems-level pinch points and synergies for the future application of a circular economy framework for construction demolition waste (CE-CDW) management. A qualitative coding process called purposive text analysis was used to extract, aggregate, and structurally analyze causal connections between factors impacting CE-CDW derived from 15 semi-structured interviews with relevant stakeholders in Aysén. Findings highlight recommendations for future CE-CDW policy and practice centering on well-structured and enforceable laws and regulations that can undergird effective stakeholder collaboration, market competitiveness, and infrastructure development.

Effect of the Incorporation of Recycled Aggregate from Construction and Demolition Waste on the Mechanical Strength of Silty-Cement Soil

Effect of the Incorporation of Recycled Aggregate from Construction and Demolition Waste on the Mechanical Strength of Silty-Cement Soil

Study on the performance of ternary blended cement with calcined clay and recycled concrete powder

Recycled concrete powder (RCP) has a large amount of calcium carbonate, which suggests that it can be used to make limestone - calcined clay (CC) cement (LC3) system by replacing limestone powder. So that it can promote the recycling of construction demolition waste and reduce the requirement of the natural resource for LC3. In this study, the fresh and hardened properties of CC-RCP cement system were comprehensively characterized by varying the CC/RCP ratio and dosage, including rheological, mechanical properties, hydration products and pore structure. The results indicate that the addition of CC prolong the setting time, but the effect could be mitigated by the recombination of RCP. By comparing with RCP, CC had a less obvious effect on increasing viscosity, but it could improve the shear thickening behavior of paste. In the case of less total content of CC and RCP, a ratio of 1:1 CC/RCP was better for the development of long-term strength. Whereas, with the increasing of substitution, the mixtures with CC alone or blending with RCP in a 2:1 ratio achieved higher strength. The incorporating of CC and RCP could make the conversion of C4AH13 into hemicarboaluminate (Hc) and monocarboaluminate (Mc), and it resulted in a denser structure with more medium capillary pores and gel pores than that mixtures with CC only.

3D-printable construction and demolition waste-based geopolymer: Investigating the effects of additives on engineering properties

This paper focuses on the investigating the effects of various additives on the engineering properties of construction and demolition waste (CDW)-based geopolymer mortars. In this study, low-activity CDW-based precursors, specifically brick waste (BW) and concrete waste (CW), were employed. Additionally, industrial waste-based precursors such as slag (S) and silica fume (SF) were utilized to enhance the overall composition. To facilitate activation, a 5 M solution of NaOH was used. To address the efflorescence issue prevalent in geopolymer mixtures and to eliminate potential cracks that may arise due to the dimensional stability problem of 3D-printed CDW-based geopolymer, various kind of additives including calcite, polypropylene fiber, nano SiO2, Al2O3, and TiO2, carbon nano tubes (CNTs), graphene nanoplatelet (GNP), methyl cellulose (MC), Na2SiO3, calcium oxide (CaO), calcium aluminate cement (CAC), and Ca(OH)2 were incorporated into the matrix. The research utilized a comprehensive testing methodology, allowing for a detailed exploration of various properties and the performance of the geopolymer mixtures. The results indicated that nano SiO2 and Al2O3, Na2SiO3, BW, and CAC were recognized for their positive impact on improving the mechanical properties of the geopolymer. Notably, the geopolymer exhibited an impressive compressive strength of 29.8 MPa and a flexural strength of 5.4 MPa following a 28-day ambient curing (23 ± 2 °C and 50 ± 5% relative humidity). Furthermore, the inclusion of nano SiO2 and Al2O3, GNP, MC, Na2SiO3, CaO, CAC, and Ca(OH)2 proved effective in preventing efflorescence, while MC, Na2SiO3, CaO, CAC, and Ca(OH)2 successfully mitigated cracks formation. The results also demonstrated that the CDW-based geopolymer mixture is suitable for 3D printing, displaying satisfactory buildability, shape retention, and extrudability. A thorough testing approach highlighted the effectiveness of additives in shaping the properties of CDW-based geopolymer, positioning them as promising for improvement and addressing challenges.

Impact of Recycled Concrete and Brick Aggregates on the Flexural and Bond Performance of Reinforced Concrete

The construction industry strongly relies on concrete and clay bricks for various applications. The escalating demand for these materials, driven by rapid population growth, has led to resource depletion and increased construction and demolition waste (CDW). Recycling CDW into construction materials, particularly in the form of recycled concrete aggregates (RCAs) and recycled brick aggregates (RBAs), has emerged as a promising solution. This study deals with the structural performance of concrete incorporating RCAs and RBAs. The experimental program encompasses material characterization, concrete mix design, and several tests to assess density, compressive strength, bond behavior, and flexural properties. The results indicate that the replacement of fine natural aggregate (NA) with fine RCAs or RBAs has a negligible impact on density, while the partial replacement of coarse NAs with RAs yields modest reductions in compressive strength. Notably, the bond strength between steel rebar and concrete is influenced by the type and content of RA, with specimens containing RCAs exhibiting a higher bond strength than those with RBAs. Empirical models used to predict bond strength generally align with experimental results, with conservative predictions by some models, such as ACI 318, and overestimation by others, such as models proposed by AS-3600 and CEB-FIB. The flexural tests of beams highlight the variation in stiffness and load-bearing capacity with the proportion of NAs replaced by RAs. While beams with 50% NA replacement demonstrate comparable performance to control beams, those with 100% RA replacement exhibit lower cracking and yielding stiffness. Cracking patterns in beams with RAs differ from control beams, with RA-containing beams showing more cracks and an altered crack distribution. The findings underscore the feasibility of using recycled aggregates in construction, with partial NA replacement offering a balance between sustainable material usage and desired structural properties.

Chloride ion permeability of concrete containing recycled composite powder from building demolition waste

Buildings in the marine environment are vulnerable to chloride ion erosion, which threatens the service life of concrete structures. To facilitate the application of concrete containing construction demolition waste in the marine environment, recycled composite powder concrete (RCPC) was prepared using recycled composite powder as cement substitute. The chloride ion permeability of RCPC was evaluated by chloride ion diffusion test and rapid chloride ion migration test (RCM). The chloride ion permeability of RCPC continued to enhance with growing content of recycled composite powder. During the immersion age, the surface chloride ion content of the samples containing recycled composite powder increased by an average of 18.3–65.3% over the control group, with a corresponding average increase in chloride ion diffusion coefficients ranging from 17.0% to 31.5%. The chloride ion migration coefficients in the RCM test raised by 9.5–24.7%. A series of microscopic tests such as nuclear magnetic resonance (NMR), X-ray diffraction (XRD) and scanning electron microscope-energy dispersive spectrometer (SEM-EDS) suggested that the total porosity increased by 11.9–29.5% with the addition of recycled composite powder. The chloride ion diffusion coefficients exhibited a linear increase with growing total porosity and porosity of capillary pores, whereas an exponential increase with the porosity of transitional pores. The poor reactivity of the recycled composite powder resulted in a looser microstructure and weakened chloride binding capacity, and these factors boosted chloride ion transport. A chloride ion diffusion model of RCPC considering the time dependence of chloride ion transport was developed, and the reliability of the model was verified by experimental data.

Performance Study of Sustainable Concrete Containing Recycled Aggregates from Non-Selected Construction and Demolition Waste

In the present study, we investigated the mechanical performance of concrete composed of non-selected construction and demolition waste (C&DW) sourced from both old and new sections of an inactive waste landfill site in Karaj, Iran. Initially, we determined the composition of the coarse and fine C&DW used in concrete production. Subsequently, we meticulously examined the physical and chemical properties of both the C&DW and virgin materials to enable thorough comparisons of the results. We then conducted experimental analyses on 33 concrete mixtures containing recycled C&DW, utilizing various tests, including a compressive strength test (CST) for cylindrical and cubic samples, modulus of elasticity (MOE), wide wheel abrasion test (Capon test), British pendulum number (BPN), and ultrasonic pulse velocity (UPV) test. We considered both non-separated fine and coarse C&DW at different replacement ratios in the recycled concrete (RC). Our findings indicate that using non-separated coarse and fine C&DW in concrete yielded satisfactory results, leading to significant savings in virgin materials required for concrete preparation and promoting sustainable development. Furthermore, non-selected C&DW proved to be a viable sustainable material for similar concrete applications. The results revealed a decrease in brick material consumption in various constructions over the past 20 years in Karaj, contributing to the enhanced strength of C&DW concrete. However, the presence of clay minerals in aged landfill sites can adversely affect concrete performance as a potential destructive factor. Despite the possible negative impact of incorporating fine recycled C&DW materials on concrete mechanical performance, the Capon test results demonstrated that the presence of coarse C&DW can enhance concrete’s wear resistance.

ВЛИЯНИЕ МИКРОБНОЙ КАРБОНАТНОЙ БИОМИНЕРАЛИЗАЦИИ НА ПРОЧНОСТЬ ЦЕМЕНТНОГО КАМНЯ

An intensive urbanization, renovation of housing stock, emergencies and natural disasters lead to difficulties arise in the management of concrete waste. In this regard, recycling construction and demolition waste is an effective solution for saving material and energy resources in the construction field. The article discusses the possibility of optimizing the structure and increasing the strength characteristics of concrete by selecting the grain composition of the aggregate based on recycled concrete scrap and the use of microbial carbonate biomineralization. The distribution of aggregate grains (0.315–5 mm), which is crushed ordinary stone SKTs, into fractions has an impact on the nature of the formation of contact zones between the cement matrix and the aggregate. This determines a decrease in strength characteristics according to the following relationship: with a decrease in the size of the aggregate, the strength of cement concrete increases. The addition of a biomineralizing solution to the cement mixture leads to improved adhesion of the cement paste to the surface of the aggregate due to the formation of additional crystallization centers in the area of the contact layer, clogging of the pore space with induced new formations, which increases the strength of concrete, both at brand age and in the forecast period.

Solar radiation powered biodiesel synthesis using C&D waste catalyst – a novel approach

A significant amount of construction and demolition waste is generated in India every year. The proper management of this waste has become a crucial concern due to fast urban growth, building projects, and increased construction work. The volume of this waste is substantial, which can harm the environment, deplete resources, and pose health risks if not handled well. This study presents an innovative method for biodiesel synthesis, addressing the challenges of construction and demolition (C&D) waste management and renewable energy integration. The research introduces a novel catalyst derived from C&D waste through a calcination process, offering an eco-friendly solution for waste repurposing. This catalyst demonstrates potential for sustainable biodiesel production, marking a significant advancement in waste management practices. Furthermore, a pioneering solar-powered reactor is utilized for biodiesel synthesis, achieving an impressive 92.2% conversion rate under specific conditions. The system's energy efficiency, calculated as [Formula: see text], surpasses conventional methods, highlighting its potential for reducing energy consumption and environmental impact. Moreover, the produced biodiesel meets ASTM D6751 standards, ensuring quality and compatibility with industry requirements.

Highly efficient activation of peroxymonosulfate by calcinated construction & demolition waste powder with free radical generation for organic pollutant degradation

BackgroundA simple, efficient and cost-efficiency peroxymonosulfate (PMS) oxidation process for organic pollutant removal is expected. This research aims to investigate the feasibility of construction & demolition waste (C&D waste) as recycled material for organic pollutant degradation. MethodsC&D waste was novelty introduced into the advanced oxidation process for organic pollutant removal. Taking phenol as the target pollutant, the effects of C&D waste loading, PMS concentration, particle diameter and solution pH were all investigated in this study by a series of batch tests and spectrometry measurements. Significant findingsBoth the intrinsic oxidation power of PMS and the adsorption of the pretreated C&D waste were negligible under this CDW/PMS system. However, calcinated C&D waste, with calcium silicate generation, enhanced the degradation efficiency of target organic pollutant by promoting the decomposition of PMS to generate •OH and SO4•−. Both •OH and SO4•− had been detected through the free radicals quenching tests and electron paramagnetic resonance (EPR) spectrometry. Except for high temperature pretreatment, the micro C&D waste after mechanical treatment could also improve the organic pollutant degradation efficiency with a high kinetic rate as a bonus especially for the introduced powder at low doses.