Demolition Waste Materials Research Articles

A Review paper on Durability Studies on Construction and Demolition Waste Material

The global rise in construction and demolition (C&D) waste generation presents significant challenges and opportunities for sustainable construction practices. This study examines the durability performance of concrete made by replacing 30% of natural coarse aggregates with recycled coarse aggregates derived from C&D waste. The research aims to evaluate the feasibility of using recycled materials in structural applications by conducting a series of durability tests, including assessments of resistance to freeze-thaw cycles, sulfate attack, chloride ion penetration, and carbonation. Concrete specimens incorporating 30% recycled coarse aggregates were prepared and tested, and their performance was compared to that of conventional concrete. The results indicate that while there is a noticeable impact on certain mechanical and durability properties, the modified concrete exhibited acceptable performance under specific conditions. Strategies for enhancing the durability of recycled aggregate concrete, such as incorporating supplementary cementitious materials, were also investigated. The findings suggest that partial replacement of coarse aggregates with recycled materials can be a viable solution for sustainable construction, provided that appropriate mix design adjustments are made. This research contributes to understanding the long-term behavior of recycled aggregate concrete and provides a basis for developing guidelines for its use in various construction applications.

Study on the mechanical property and durability of alkali-activated seawater and sea sand recycled aggregate concrete

This study investigates the potential of Alkali-Activated Seawater Sea Sand Recycled Aggregate Concrete (ASSRAC) as a novel sustainable construction material. By utilizing recycled aggregates from construction and demolition waste, seawater, sea sand, and alkali-activated materials such as fly ash and blast furnace slag, this innovative concrete aims to mitigate carbon emissions from cement production and optimize resource usage. The impact of recycled aggregate replacement rate, water-to-binder ratio, and sand type on the compressive strength of ASSRAC was examined through analysis of variance. Cylindrical axial compression and prism flexural tests were conducted to evaluate the long-term performance of ASSRAC under seawater immersion. The results indicate a decrease in compressive strength with higher recycled aggregate replacement rates and water-to-binder ratios, with recycled aggregates being the primary weak link. Additionally, increasing the water-to-binder ratio hampers hydration by diluting alkali activators, weakening polycondensation reactions. Under seawater immersion, ongoing reactions foster denser C-(A)-S-H structures, enhancing compressive strength and elastic modulus over time. Moreover, higher recycled aggregate replacement rates result in improved ductility, attributed to reactions between the old mortar on recycled aggregate surfaces and slag/fly ash at interfaces. For specimens immersed for 0 and 90 days, most theoretical models accurately predict results, except for the CEB-FIP model, which only accurately reflects the stress-strain curve at 180 days. The seawater-sea sand group's flexural strength initially exceeds that of the freshwater-river sand group due to accelerated early hydration, but this advantage diminishes over time due to high salt content.

Sustainable management of construction and demolition waste in Bangladesh to promote resource recycling

ABSTRACT This study conducted during the fiscal year of 2022–2023 endeavors to offer waste generation rates (WGR) for different Construction and Demolition Waste (CDW) materials and analyze the financial and environmental benefits of CDW recycling at a national level. Findings from the study reveal that CDW in Bangladesh mainly consists of concrete (56%), brick (15%), mortar (9%), metal (6%), and ceramics (6%). Additionally, the collective CDW produced in six major cities studied totals 3.71 million tons (MT). The WGR of CDW is assessed through regression analysis. The mean WGR for Construction and Demolition activities in the fiscal year 2022–2023 are notably recorded at 64.68 kg/m2 and 1626.97 kg/m2, correspondingly for the 12 city corporations. The study highlights the potential for entrepreneurial initiatives in recycling materials like concrete, brick, mortar, metal, ceramics, and timber, leading to reduced CO2 emissions and energy consumption. The estimated economic value of recycling concrete, brick, and metals in major cities is approximately 104.5 million USD and 0.45 MT of CO2 reduction from recycling brick and metals from major cities.

Geopolymer-based insulated wall incorporating construction and demolition waste: Experimental assessment of thermo-physical behavior

The benefit of the application of geopolymers in the building sector is nowadays undisputed. In addition to good structural characteristics, these are characterized by interesting thermophysical properties, obtained through a production process, that reduces CO2 emissions and could incorporate recycled material, thus responding to environmental sustainability. However, it is noted the lack of studies regarding the in-field thermal performance. Thus, the aim of the present study is to investigate the thermal performance, under real conditions, of an innovative geopolymer-based insulated wall. It incorporates over 70% of net weight of Construction and Demolition Waste materials. The wall is conceived within the European project called “Green INSTRUCT” aimed to realize modular prefabricated building elements, for retrofitting and new construction of buildings. Two wall prototypes are analysed, which differ for the type of lightweight aggregate of geopolymer matrix, 3% by weight: expanded polystyrene or extruded polystyrene. The study refers to almost one year of continuous monitoring within a full-scale test room located in southern Italy. The method developed consists of 5 different phases and it involves also a normative-insulated reference wall. The results show higher insulation level of the proposed wall package, with a reduction of the heat flux of about 66% and more stable indoor thermal conditions, compared to the reference wall. Also the inertial properties are satisfactory, showing an experimental decrement factor equal to 0.05 and a time-shift of decrement factor higher than 6 h. All told, the experimental results can provide valuable insights into the real impact of innovative technology on energy efficiency and indoor thermal comfort.

Investigation of mechanical, durability, and thermal properties of sustainable self-compacting mortars containing construction demolition waste and supplementary cementitious materials

This study aims to produce sustainable self-compacting mortar (SSCM) to provide solutions to the waste generation caused by the construction industry and to provide alternative solutions to the increasing consumption of natural resources and cement. In SSCM designed as 12 different mixtures; recycled sand (RCS) and pumice were used as aggregate and silica fume (SF) and fly ash (FA) were used as supplementary cementitious materials (SCM). The mechanical, durability, and thermal properties of the produced SSCM were investigated. Compressive and flexural strengths were determined at age of 7, 28 and 90 days. Significant increases in flexural and compressive strengths were observed for 10 % SF and 10 % FA substitutions. After 90 days of water curing, the specimens were exposed to high temperature. A decrease of up to 93.4 % in flexural strength was observed after high temperature effect. Sorptivity, water absorption and porosity values were determined. Thermal conductivity test was also performed on the specimens. Significant changes were observed due to the use of SCM. The global warming potential (GWP), and energy consumption (EC) were considered to evaluate environmental properties. Significant reductions in GWP and EC values were observed for mortar series with 30 % SCM. Significant gains were achieved in economic properties due to the use of SCM, with total costs decreasing by approximately 10 %, especially in series with 30 % SCM. SSCM produced using recycled aggregates and SCMs have provided significant contributions to sustainability.

Development of a 3D Digital Model of End-of-Service-Life Buildings for Improved Demolition Waste Management through Automated Demolition Waste Audit

This paper presents the development of a 3D digital model of end-of-service-life buildings to facilitate a step change in preparation of pre-demolition protocols that can eliminate problems of inadequate documentation and extensive time spent in preparing pre-demolition audits. The 3D digital model consists of the following four main components: (i) digitization of paper-based drawings and their conversion to CAD; (ii) automated generation of a 3D digital model from CAD; (iii) corrections to the 3D digital model to account for changes in the lifetime of a building; (iv) a sub-model for performing pre-demolition audit. This paper proposes the innovative approaches of incorporating a minimal amount of human intervention to overcome numerous difficulties in automated drawing analysis, application of augmented reality (AR) in corrections to the 3D digital model, and data compatibility for pre-demolition audit. These processes are demonstrated using one building as case study. Using the digital model, a pre-demolition audit can be prepared in minutes rather than the many days required in current practice without a digital model. The accurate quantification of the quantities and locations of different demolition waste materials and products in buildings to be demolished will enable a systematic and quantitative evaluation of potentials of material and product reuse and eliminate contamination of different demolition waste streams (which may contain hazardous waste), which is the main cause of environmental degradation and downcycling of demolition waste materials.

Vision-based method to identify materials transported by dump trucks

Construction and demolition waste (C&DW) materials are highly valuable as, in most cases, they can be reused. In other cases, such material can be highly pollutant. Therefore, their traceability becomes very important in the frame of sustainable development. Computer vision-based solutions have the potential to recognize different forms of construction waste material. This study provides a vision-based framework to identify C&DW transported by dump trucks before entering landfills. The proposed framework is composed of two main models: a semantic segmentation model to isolate the content of the dump truck, and a classification model to identify the C&DW in the image patches created by the superimposition of the segmentation mask and the input image. The results of the classification model are used to assess the homogeneity of the content and the main type of waste material contained in the dump truck. The semantic segmentation model achieves an IoU of 0.945 and an average inference time of 0.388s on a CPU, and the classification model achieves a F1-score of 0.965. To validate the proposed framework, various data collection attempts have been conducted in real landfills. The validation tests achieved an average accuracy of 99.0% in identifying the main material in the dump truck and an average accuracy of 94.8% in evaluating its homogeneity. The developed framework performed its inference in 0.899 s on a CPU.

Using construction and demolition waste materials to alleviate the negative effect of pavements on the urban heat island: A laboratory, field, and numerical study

In this study, construction and demolition waste (CDW) materials, including waste clay bricks, concrete, and glass, were used as aggregates of chip seal layers to enhance the reflectivity and reduce the temperature of asphalt pavements as an urban heat island (UHI) mitigation policy. UHI is an urban area that has a higher temperature in comparison to its suburbs. As considerable parts of cities are covered with asphalt pavements, their heat absorption and heat release can directly affect the UHI. Four types of chip seal layers, containing CDW aggregates were prepared in this study. The reflectivity and cooling effects of asphalt pavement coated with the developed chip seals were then evaluated with laboratory, field experiments, and computational fluid dynamics (CFD) simulation. Regarding the laboratory methods, UV-Visible-NIR spectrometer reflectance, a trident thermal properties measurement, and solar simulation cooling effect were used. Besides, the albedo and cooling effects of the developed chip seals were evaluated with a pyranometer and thermocouples through a field experiment. The indoor reflectance test showed yellow and red brick chip seals reflected almost 136 % higher than the aged asphalt pavement, followed by concrete chip seals with 80 % higher solar reflectance. Besides, the surface temperatures of yellow brick, red brick, and concrete chip seals were 23 %, 18 %, and 15 % cooler than the hot mix asphalt (HMA) specimens. More importantly, clay brick chip seals had the lowest nighttime heat release, followed by the concrete chip seal. The field test indicated that the albedo of yellow brick was 2 and 6 times higher than the aged and new HMA, causing 17 % and 27 % lower surface temperatures. The numerical models also revealed that using the yellow brick and concrete chip seals decreased the surrounding air temperature at least by 18 % and 14 % respectively. Overall, the numerical modeling, laboratory, and field tests showed similar results, indicating the benefits of using clay bricks and concrete aggregates for chip seal development, which can mitigate the UHI effectively.

Rheological properties of high-performance SCC using recycled marble powder

Due to the impacts of cement manufacturing and depletion of the natural aggregates for concrete production, recycling of construction and demolition waste materials has become an alternative replacement to natural materials that lower their consumption and satisfy the environment. One of these alternatives is replacing cement with recycled materials from marble, ceramic, granite, and concrete wastes or even replacing the coarse aggregate with crushed marble and other stone wastes. Marble, granite, and natural stone wastes rapidly increase each year due to unmanaged waste disposal processes and the incremental increase in construction potential. Marble slurry, which comes from washing and cleaning marble surfaces, shows a filler effect by giving the concrete a denser and homogenous structure. This study evaluates the marble filler effects on the rheology in the fresh state of self-compacting concrete (SCC) through four SCC mixes by incorporating 10% marble powder (MP) and 33% fly ash (FA) as a partial ordinary Portland cement (OPC) replacement. Tests on paste and mortar were conducted to assess the suitability of the marble dosage on the water content and the superplasticizer amount. Spread flow and V-funnel tests were assessed. The results showed that mixes with MP required additional mixing water to ensure the same workability. Regardless of the high viscosity and air content, the overall developed marble SCC mixes reduced the cement quantity by up to 11% and provided excellent rheological properties like that of the reference mix. Besides the economic benefits, this transformation of waste to valuable materials involves environmental advantages and sustainability promotion.

Using ceramic demolition wastes for CO2-reduced cement production

This study focuses on assessing the pozzolanic potential of two types of ceramic demolition waste, namely terracotta roof tiles and sanitary porcelain, as substitutes for traditional calcined clays in blended and limestone calcined clay (LC3) cement production. Experimental methods employed include the modified Chapelle test and XRD for pozzolanic activity evaluation, flexural and compressive strength tests, capillary absorption measurements, and SEM for microstructure analysis. Mortars containing 10%, 20%, and 30% ceramic powders and 5%, 10%, or 15% limestone filler were tested. The findings showed that porcelain powders exhibited lower pozzolanic activity due to their lower surface area and higher firing temperature of the material. Up to 20% substitution of OPC with terracotta had minimal strength impact, with a 103% strength activity index (SAI) at 90 days. Ultrafine terracotta powder showed promise in LC3 production with up to 30% OPC substitution, achieving a 97% SAI after 90 days. The poor mechanical properties of porcelain-containing mortars were explained by surfactants present in sanitary porcelain. This research informs the cement and processing industries on the potential use of specific ceramic demolition waste materials in eco-cement production, offering insights into blended pozzolanic cements and LC3 formulations, with the goal of reducing the carbon footprint of cement manufacturing.

A life cycle assessment of building demolition waste: a comparison study

Globally, building demolition waste constitutes a considerable environmental problem. The environmental implications are not only associated with volume but also with carbon embodied in the waste. These adverse environmental impacts associated with the generated waste can be minimised through appropriate waste management strategies. This study proposed a mathematical model from the end-of-life perspective to examine two waste treatment methods. The model was illustrated by a case study of three approved building construction systems by a current UK supermarket referred to as construction methods CM1, CM2 and CM3 to assess the construction system with the least carbon dioxide emission. Landfilling and recycling were assumed as waste treatment methods to examine the preferable waste treatment method. Results showed that recycling is the most preferred method of waste treatment method of the supermarket. This was revealed by the amount of demolition waste material recycled (more than 90%) from each of the CM compared with the volume of waste materials landfilled (<10%) and the associated carbon dioxide emissions. Steel has the highest carbon reduction potential contributing ∼80% in each case study compared with concrete ∼1%. Finally, CM1 has the lowest carbon dioxide emission, with both CM2 and CM3 emitting ∼3% more.

Sustainability Assessment of Construction and Demolition Waste Material

Construction and demolition waste (C&DW) constitutes a substantial portion of waste generated during construction activities, ranging from 15 to 30% globally. This waste category poses environmental threats, impacting health and the environment, particularly in Nigeria. This research investigates the environmental and economic implications of C&DW in the Nigerian construction industry, systematically addressing types, causes, and disposal methods. The study explores potential reuse through Circular Economy (CE) strategies. The literature review encompasses CE principles and Construction Waste Management in Nigeria. Employing quantitative research methods, questionnaires were administered to a selected group, revealing respondents' recognition of economic benefits from proper waste management. However, a lack of incentives and facilities for diverse disposal methods emerged as a significant challenge. Recommendations include government regulations, incentives for recycling facilities, and educational initiatives emphasizing the advantages of a circular economy. Emphasis is placed on effective information dissemination to stakeholders. This research contributes valuable insights for industry professionals, policymakers, and government entities, offering a foundation for sustainable waste management practices in the Nigerian construction sector.

An Automated Classification of Recycled Aggregates for the Evaluation of Product Standard Compliance

Nowadays, recycling of construction and demolition waste (C&DW) is a challenging opportunity for the management of such end-of-life (EOL) materials through alternative methods to environmentally unsustainable methods (i.e., landfilling). In order to make recycling processes more effective, quality control systems are needed. In this work, the possibility of developing a sensor-based procedure to recognize different demolition waste materials from a recycling perspective was explored. An automatic recognition of different predefined constituent classes of recyclables (i.e., concrete, mortar, natural stones, unbound aggregates, clay masonry units, bituminous materials) and contaminants (i.e., glass, metals, wood, cardboard, and gypsum plaster), as established by an European standard, was carried out using hyperspectral imaging (HSI) working in the short-wave infrared (SWIR) range (1000–2500 nm). The implemented classification strategies, starting from the collected hyperspectral images of the analyzed constituents, allowed for the identification of the different material categories. Two main models were built for identifying contaminants in recyclable materials and categorizing material groups based on technical specifications. The results showed accurate category identification with Sensitivity and Specificity values over 0.9 in all models. The possibility of performing a full detection of C&DW recycling products can dramatically contribute to increasing the quality of the final marketable products and their commercial value, at the same time reducing the amount of waste and the consumption of primary raw materials.

Applicability of machine learning models for the assessment of long-term pollutant leaching from solid waste materials

Column leaching tests are a common approach for evaluating the leaching behavior of contaminated soil and waste materials, which are often reused for various construction purposes. Standardized up-flow column leaching tests typically require about 7 days of laboratory work to evaluate long-term leaching behavior accurately. To reduce testing time, we developed linear and ensemble models based on parametric and non-parametric Machine Learning (ML) techniques. These models predict leachate concentrations of relevant chemical compounds at different Liquid-to-Solid ratios (LS) based on measurements at lower LS values. The ML models were trained using 82 column leaching test samples for Construction and Demolition Waste materials collected in Germany during the last two decades. R-Squared values measuring models’ performance are as follows: Sulfate = 0.94, Vanadium = 0.97, Chromium = 0.82, Copper = 0.92, group of 15 (US-EPA) PAHs = 0.98 (values averaged over predictive models for LS 2 and 4). Sensitivity analysis utilizing the Shapley Additive Explanation value indicates that in addition to the concentrations of the considered compound at LS<=1, electrical conductivity and pH are the most critical features of each model, while concentrations of other compounds also play a minor role.

Gasified olive stone biochar as a green construction fill material

The rapid growth in biomass waste generation from industrial and agricultural sectors has emerged as a significant global challenge. One potential solution to address this challenge is to utilize biomass waste materials as sustainable construction materials, which can mitigate landfilling concerns, reduce the need for natural materials and ultimately minimize carbon emissions. This study focused on the evaluation of the engineering and environmental properties of olive stone biochar (OSB) as a green construction fill material. OSB is the solid residue resulting from biomass gasification in a waste-to-energy plant. The properties of OSB were compared to those of recycled glass (RG), a mainstream construction and demolition (C&D) waste material in Australia, for benchmarking purposes. Extensive laboratory tests were conducted on unbound OSB, RG and OSB/RG blends. The results indicated that gasified OSB was a stable biomass material and it exhibited good engineering performance when used as a construction fill material. In cases where higher strength was required, OSB can be blended with RG to achieve higher values of California bearing ratio (CBR) and resilient modulus. All OSB/RG blends were found to meet the minimum CBR requirement for subgrade materials as specified by the local road authority. Environmental tests revealed that the application of OSB as a construction fill material would not have any adverse environmental impact. This research highlighted the potential for OSB to replace virgin quarry materials in geotechnical fill and road subgrade applications. The involvement of biochar as a carbon sink in construction works also aligns well with the strategy to manufacture green materials within the construction industry, as it serves the dual purpose of locking carbon in a stable state within infrastructures and boosting waste reutilization rates simultaneously.

CO2 capture using lithium-based sorbents prepared with construction and demolition wastes as raw materials

CO2 capture was tested using lithium silicates prepared with construction and demolition waste materials (CDWM) to climate change mitigation. Four types of CDWM with high silicon and aluminum content were evaluated: sand, block, ceramic sanitary ware (CSW), and concrete wastes. CDWM were characterized by XRF, XRD and SEM-EDS; subsequently, the non-conventional precursors were mixed with LiOH and thermally treated in two stages: at 250 and 550 °C. Li4SiO4 was synthesized using conventional SiO2, applying the same synthesis method, and used as a reference. Li4SiO4, Li2SiO3 and LiAlO2 crystalline phases were obtained from all CDWM. Additionally, Li2CaSiO4 was detected in the case of wastes with high calcium content (block and concrete). The prepared Li4SiO4 samples were evaluated using the TGA technique for CO2 capture in dynamic and isothermal modes. The bulk CO2 adsorption in the Li4SiO4 prepared with CDWM started at a lower temperature (380 °C) than the material prepared with conventional precursors (500 °C). The temperature of CO2 sorption maxima was estimated at around 600 °C, being the Li4SiO4 prepared with block waste the material with the best performance. According to the isothermal analysis, the block-derived lithium silicate achieved a maximum CO2 capture capacity of 183 mg/g at 580 °C with PCO2 = 0.2; the desorption was observed above this temperature. The kinetic results (Avrami Eroffev model) were similar to those of Li4SiO4 prepared with conventional SiO2. Moreover, the stability of the materials was demonstrated during 20 cycles of the sorption-desorption process, displaying a constant sorption capacity of 180 CO2 mg/g.

Geotechnical Characterization of Construction and Demolition Waste Material Blended with Sandy Soil

Geotechnical Characterization of Construction and Demolition Waste Material Blended with Sandy Soil

Use of Recycled Construction and Demolition Waste Material in Soil Stabilization

Abstract: Along with the growth of the construction sector, waste from construction and demolition has steadily increased. The Building Materials Promotion Council (BMPTC) estimates that India generates 1504.444 million tons of construction and demolition waste (C&amp;D) annually. However, the official capacity is 6,500 tons per day (TPD), which is only about 1%. This article investigates the properties of black cotton soil and explores the use of recycled C&amp;D waste from soil to stabilize black cotton soil. This study focuses on the inexpensive and environmentally friendly properties of C&amp;D waste as a soil stabilization additive. Testing was conducted using different percentages of recycled C&amp;D waste at rates of 15%, 20% and 25% to increase the strength of the Black Earth. The California Bearing Capacity Ratio (CBR) is 7.77 % to 12.36%, and the maximum dry density of (MDD) decreased from 2.104 g/cm3 to 1.86 g/cm3 and Optimum Moisture Content (OMC) showed change and increased from 13.15% to 18.04% with the addition of 25% C&amp;D waste.

Using Construction and Demolition Waste Materials to Develop Chip Seals for Pavements

Construction and demolition waste (CDW) materials account for a considerable part of waste materials throughout the world. As these materials are not usually recycled, reusing them in construction projects is of major significance. In this study, recycled concrete, bricks, and glass were used as 100% aggregates of chip seal, which is a corrective or preventive pavement maintenance method. A cationic rapid setting (CRS-2) bitumen emulsion was also used to prepare the chip seal. Different tests, including the sand patch test, sweep test, British pendulum tester (BPT), interface bond, and Vialit test, were conducted. The results of these tests revealed that all these materials had sufficient aggregate embedment for vehicle speeds of more than 70 km/h, and the number of chips was less than 10%, indicating their good performance. All developed chip seals ranked as high skid resistance pavement at ambient temperature. The chip seals developed with concrete and glass showed the best adhesion with an asphalt pavement surface and an aggregate–bitumen adhesion at very cold and ambient temperatures due to the fact of their chemical compositions. Overall, using concrete aggregates to develop chip seals under different traffic loads is recommended. Finally, these findings can provide a novel approach for recycling CDW materials with low costs.

Geothermal Pavements: Experimental Testing, Prototype Testing, and Numerical Analysis of Recycled Demolition Wastes

Geothermal pavements have the potential to reduce the pavement surface temperature by circulating fluid in pipes within the pavement structure. This research investigated an innovative geothermal pavement system with multiple benefits, such as reducing the surface temperature and harvesting heat energy for power generation. This research aimed to provide an understanding of the mechanical properties of geothermal pavements constructed with construction and demolition (C&amp;D) waste materials through large-scale physical testing, experimental testing, small-scale prototype testing, and numerical simulation. The mechanical properties of the geothermal pavement system were assessed under long-term traffic loading conditions using a prototype test system. The repeated load triaxial and repeated-load California bearing ratio tests were also undertaken to evaluate the effect of pipe inclusion on the permanent deformation, stiffness, and strength of the pavement base. A numerical model was subsequently developed and calibrated using the data from small-scale prototype testing. In addition, the effects of the flow rate and pipe materials on the thermal performances of the geothermal pavements were also investigated in this research. The inclusion of pipes in the pavement base layer was found to have negligible detrimental effects on the deformation behavior of RCA. The resilient moduli of recycled concrete aggregate (RCA) samples slightly decreased with the inclusion of pipes. An HDPE pipe reduced the stiffness of the RCA + HDPE mix. On the other hand, a copper pipe’s high stiffness improved the mix’s strength. The numerical simulations indicated that for the HDPE pipe, increasing the flow rate from 500 mL/min to 2000 mL/min reduced the surface temperature by approximately 1.3%, while using the copper pipe resulted in an approximately 4% further decrease in the surface temperature compared to the HDPE pipe.