Construction And Demolition Waste Research Articles

Optimizing waste handling with interactive AI: Prompt-guided segmentation of construction and demolition waste using computer vision

Optimized and automated methods for handling construction and demolition waste (CDW) are crucial for improving the resource recovery process in waste management. Automated waste recognition is a critical step in this process, and it relies on robust image segmentation techniques. Prompt-guided segmentation methods provide promising results for specific user needs in image recognition. However, the current state-of-the-art segmentation methods trained for generic images perform unsatisfactorily on CDW recognition tasks, indicating a domain gap. To address this gap, a user-guided segmentation pipeline is developed in this study that leverages prompts such as bounding boxes, points, and text to segment CDW in cluttered environments. The adopted approach achieves a class-wise performance of around 70 % in several waste categories, surpassing the state-of-the-art algorithms by 9 % on average. This method allows users to create accurate segmentations by drawing a bounding box, clicking, or providing a text prompt, minimizing the time spent on detailed annotations. Integrating this human–machine system as a user-friendly interface into material recovery facilities enhances the monitoring and processing of waste, leading to better resource recovery outcomes in waste management.

Systematic Review of Construction Waste Management Scenarios: Informing Life Cycle Sustainability Analysis

Abstract Purpose Construction and demolition waste (CDW) is increasing due to rapid urbanization. An estimated 35% of CDW is disposed of in landfills worldwide. Thus all available strategies for minimizing the environmental and economic impacts of CDW are explored. This study reviews the use of recycled construction and demolition waste as substitutes for primary materials as well as strategies for the reuse of materials that lead to the circular economy. The aim of this study is to analyse previous literature on CDW that use life cycle analysis and contribute to the circular economy. Methodology A bibliometric analysis and systematic critical review is presented to investigate the contribution of construction materials to life cycle sustainability assessment (LCSA). The Scopus database was the main source of data reviewed. The geographical distribution, main research sources, and keywords co-occurrence were analyzed for 69 peer-reviewed articles and conference papers. Findings Most studies compared the life cycle assessment (LCA) and life cycle cost (LCC) of alternative concrete recycling methods or using waste instead of aggregates in concrete. Recycling or reuse of concrete, bricks, wood, gypsum, and steel are the most common materials studied in previous research. A knowledge gap is proposed for future research. Originality The knowledge gaps identified focus on wood waste and concrete. Currently it is not clear which of the options proposed is the most sustainable.

Risk-averse distributionally robust optimization for construction waste reverse logistics with a joint chance constraint

The uncertainty of the amount of construction and demolition waste (CDW) generation affects the CDW reverse logistics network service level. We investigate a CDW reverse logistics network location-routing problem considering uncertainties. To minimize the total social cost, a two-stage risk-averse distributionally robust optimization model is developed, which aims to optimize the location and number of CDW disposal facilities and the CDW transportation scheme. We introduce the mean-conditional value at risk measure and a joint chance constraint into our model to consider the government’s risk aversion. The above model is approximated as a standard second-order cone programming model (SOCP) considering a special case. To exactly solve the SOCP, we design an outer approximation algorithm. Several performance tests and a case study are proposed, and sensitivity analysis provides helpful managerial insights.

Operational Decisions of Construction and Demolition Waste Recycling Supply Chain Members under Altruistic Preferences

How to efficiently and greenly dismantle abandoned buildings and reuse them is a dilemma facing the building material industry’s low-carbon objective. However, relevant studies ignore the influence mechanism of altruistic preferences of enterprises on green dismantling technology in supply chains. Driven by filling this theoretical gap, this paper firstly integrates reciprocal altruism theory and the Stackalberg game method and constructs a construction and demolition waste (CDW) recycling supply chain system consisting of a recycler and a remanufacturer, in which enterprises’ altruistic preferences are considered. The main theoretical outcomes of this paper are as follows. (1) In the case of unilateral altruism, enterprises’ altruistic preference behaviors help in increasing the green dismantling technological level and the amount of CDW recycling. Under the mutual altruism model, the influence of the recycler’s altruistic preference degree on the amount of CDW recycled hinges on the remanufacturer’s altruistic preference degree. (2) The utility of the enterprises and the green dismantling technological level are optimized under the mutual altruism model. (3) In a system of unequal power, unilateral “goodwill” by the follower will have a negative effect on their own interests; the leader plays a crucial role in facilitating equal cooperation and realizing win–win situations. This paper enriches the reciprocal altruism theory in waste management. It also helps in providing guidance for the recycler and remanufacturer in making operational decisions.

Life Cycle Carbon Assessment of Mortars with Carbonated and Non-Carbonated Recycled Aggregates

Global warming is one of the most important issues that the world is currently facing. The cement industry accounts for around 7% of total global CO2 emissions. According to the 13th United Nations Sustainable Development Goals, cement plants must become carbon neutral by 2050. This neutrality may be achieved by a reduction in CO2 emissions complemented with carbon capture, utilization and storage (CCUS) technologies. In accordance with these sustainable goals, several approaches have been studied. This paper investigates life cycle carbon of mortars produced with carbonated recycled aggregates. In previous works, the carbon dioxide capture capacity of construction and demolition waste (CDW) was analysed, and mortars with CDW recycled aggregates submitted to high levels of CO2 were evaluated in terms of their mechanical performance. This paper focus on the life cycle carbon impact assessment (LCCA) of industrial mortar formulations in a cradle-to-gate boundary. This assessment is carried out through a global warming potential environment impact assessment, since it represents the amount of CO2 equivalent that is sent to the atmosphere and contributes to the “greenhouse effect”. This LCCA includes the impacts associated with the treatment and additional transportation routes of the recycled aggregates. With this work, it was found that mortars with carbonated recycled aggregates have a considerably lower global warming potential impact than mortars without recycled aggregates. The mortars with recycled aggregates presented lower CO2 emissions of up to 6.31% for 100% incorporation of non-carbonated recycled aggregates. These values were incremented with the carbonation of the recycled aggregates, achieving a reduction of CO2 emissions of up to 36.75% for 100% of incorporation.

Microstructural behavior of mortars containing thermo-activated crushed demolition residue (TCDR)

The construction industry has been constantly expanding and is, consequently responsible for a high consumption volume of natural raw materials and for generating large amounts of waste. In detriment of this scenario, this research proposes the reuse of Construction and Demolition Waste (CDW), especially that from plaster for making mortars. The residue was thermo-activated at 650 °C for a period of 2h, a heating rate of 10 °C/min, it was crushed in a jaw crusher and passed through an ABNT N° 16 sieve. The mortars were prepared with a (cement:sand) ratio of 1:6 by mass, the sand was partially replaced by the residue in proportions of 0, 10, 20 and 30%, using Ordinary Portland Cement (OPC). Tests were carried out on consistency index, mass density, incorporated air content, isothermal calorimetry, water retention, mass density in the hardened state, flexural strength, compressive strength, water absorption and void index, in addition to testing techniques characterization, such as laser granulometry, pozzolanic activity using the Modified Chapelle method and Lúxan method, X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) as well as Mercury Intrusion Porosimetry (MIP). It was possible to observe that the residue has amorphous phases, through XRD and heterogeneous nucleation of smaller particles, proven by the calorimetry test, contributing to the increase in mechanical strength. The results indicate that the mixture with 30% replacement achieved a greater increase in mechanical strength, lower absorption rates and consequently, a reduction in the distribution of pore sizes.

Optimisation of the performance of alkali-activated mortars using CDW binders from different sources

This study investigates the fresh-state properties and the hardened-state physical and mechanical properties of a total of 64 alkali-activated mortars incorporating different wastes as binders, such as fly ash (FA), recycled concrete (RC), recycled brick (RB), and recycled tile (RT). These waste materials were activated using sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). Linear regression analysis was employed to evaluate the impact and significance of Na2O concentration (9 % or 15 %), modulus of silica (0.5 or 1), curing time in the oven (24 or 48 h), and temperature (50 °C or 70 °C) on the properties of the mortars. The results, analysed using ANOVA, indicate that all properties were affected by these parameters, except for the initial curing time in the oven for mortars made with construction and demolition waste (CDW), which showed no significant differences between periods of 24 and 48 h. Compared to mortars produced with RC, the contribution of these parameters to mechanical properties was more prominent in the mixes with RT and RB. The highest compressive strength at 28 days, for the mortars with CDW binders, was obtained by incorporating RT with 12 % of Na2O, modulus of silica of 1 and 70 °C for 48 h of initial curing, reaching 12.5 MPa. This value is 2.1 times higher than the strength obtained in mixes with RB or RC. The results also show that the performance of the mortars is highly related to the reactivity of the waste material (mortars with RT performed better) and prove that each raw material has its own optimum criterion.

Numerical study on the anti-collision performance of recycled foam concrete beam guardrail under vehicle collision

Recycled foam concrete (RFC) possessed excellent energy absorption capabilities and could be used in the anti-collision field. To address the insufficient anti-collision performance of existing guardrails, this paper presented a novel RFC beam guardrail by combining RFC with box-shaped steel shells. The quasi-static compressive tests and drop hammer impact tests were applied to analyze the static and dynamic mechanical characteristics of RFC with different densities and sand-cement ratios. Then, the vehicle collision performance of the RFC beam guardrail (RBG) and standard beam guardrail (SBG) was tested by LS-DYNA. The results showed that, compared with SBG, RBG had better guiding and energy absorption effects, reduced the peak vehicular acceleration by 44.15 % and the maximum guardrail displacement by 73.22 % during vehicle collisions, and mitigated the damage to the vehicle. Therefore, it is a viable way to utilize RFC to fabricate RBG, which could not only repurpose the construction and demolition wastes (CDW) but also acquire guardrails with enhanced anti-collision performance.

WITHDRAWN: From Debris to Innovation: Unveiling a New Frontier for Alkali-Activated Materials

Alkali-activated materials (AAMs) play a crucial role in addressing the environmental challenges of traditional construction binders by offering a lower carbon footprint alternative. Industrial by-products are utilized, reducing waste and energy consumption associated with lime and cement production. AAMs represent a sustainable innovation in the construction industry, promising significant reductions in CO2 emissions and resource utilization. This review aims to meticulously analyze the existing body of research on the potential of Construction and Demolition Waste (CDW) as an alternative precursor for producing AAMs. This review study introduces a novel angle by critically evaluating advancements in CDW processing techniques for AAM production, alongside assessing the environmental and mechanical outcomes. It pioneers bridging the gap between innovative recycling methods and sustainable construction practices. The ultimate goal is to synthesize findings into a comprehensive framework to guide future research toward optimizing CDW utilization in AAM production, thereby contributing to sustainable construction practices and the circular economy. This study stands out for its in-depth examination of CDW's role in mitigating the environmental impact of conventional construction materials, offering novel insights into the path toward sustainability in the construction industry. By critically assessing the latest advancements in CDW processing techniques and their environmental and mechanical implications, the study not only underscores the potential of CDW in revolutionizing the construction industry but also sets a new precedent in sustainability research. It bridges the crucial gap between theoretical innovation and practical application, offering actionable insights for optimizing CDW utilization in AAM production. This comprehensive analysis signifies a pivotal step towards integrating sustainable practices within the construction sector, advocating for a paradigm shift towards a circular economy that prioritizes resource efficiency and environmental stewardship.

Valorization of Fine-Fraction CDW in Binary Pozzolanic CDW/Bamboo Leaf Ash Mixtures for the Elaboration of New Ternary Low-Carbon Cement

This paper presents the characterization of a binary mixture of construction and demolition waste (CDW) and bamboo leaf ash (BLAsh) calcined at 600 °C (novel mixture) and the study of its pozzolanic behavior. Different dosages in a pozzolan/Ca(OH)2 system were employed. The aim is the valorization of fine-fraction CDW that achieves a more reactive binary mixture and allows an adequate use of CDW as waste, as CDW is a material of limited use due to its low pozzolanic activity. The pozzolanic behavior of the mixture was analyzed using the conductometric method, which measures the electrical conductivity in the CDW + BLAsh/CH solution versus reaction time. With the application of a kinetic–diffusive mathematical model, the kinetic parameters of the pozzolanic reaction were quantified. This allowed a quantitative evaluation of the pozzolanic activity based on the values of these parameters. To validate these results, other experimental techniques were used: X-ray diffraction, thermogravimetry and scanning electron microscopy. Also, mechanical compressive strength assays were carried out. The results show an increase in the pozzolanic activity of binary mixes of CDW + BLAsh for all the dosages used in comparison to the pozzolanic activity of CDW alone. The quantitative assessment (kinetic parameters) shows that the binary mixture CDW50 + BLAsh50 is the most reactive (reaction rate constant of 7.88 × 10−1 h−1) and is superior to the mixtures CDW60 + BLAsh40 and CDW70 + BLAs30. Compressive strength tests show higher strength values for the ternary mixes (OPC + CDW + BLAsh) compared to the binary mixes (OPC + CDW). In view of the results, the binary blend of pozzolans CDW + BLAsh is suitable for the manufacture of future low-carbon ternary cements.

Coevolution Mechanism of Remanufacturer–Construction Enterprise–Public in Construction and Demolition Waste Resource Utilization Projects under Green Value Co-Creation

The utilization of resources plays a crucial role in mitigating the environmental pollution issue that improper disposal of construction and demolition waste (CDW) causes. However, the slow growth of the recycled building materials market limits the development of CDW resource utilization. Green value co-creation among remanufacturers, construction enterprises, and the public in CDW resource utilization projects is an effective way to address the issue. This study, based on the theory of value co-creation, uses the evolutionary game method to construct an evolutionary game model for CDW resource utilization projects. The main conclusions are as follows: (1) When the degree of green value co-creation is 0.1 or 0.5, the remanufacturer, the construction enterprise, and the public cannot maintain a state of green value co-creation; when the degree of green value co-creation is 0.9, the remanufacturer, the construction enterprise, and the public in the CDW resource utilization project finally reach a stable state of green value co-creation. (2) When the degree of green value co-creation is 0.5, enhancing the green value co-creation willingness of the remanufacturer or the public can lead other CDW resource utilization project stakeholders to participate in green value co-creation. This study contributes to the promotion of stakeholder cooperation in CDW resource utilization projects, thus providing implications for the promotion of CDW resources.

Optimal Replacement Ratio of Recycled Concrete Aggregate Balancing Mechanical Performance with Sustainability: A Review

Significant construction and demolition waste (CDW) is produced by many useless concrete buildings, bridges, airports, highways, railways, industrial mining, etc. The rising need for new construction has increased the use of natural materials, impacting the ecosystem and incurring high costs from mining natural aggregates (NA) and processing CDW. The concept and implementation of recycled aggregate concrete (RAC) offer a sustainable solution for the concrete industry. Crushed concrete, made from recycled concrete, can be used instead of natural aggregates in structural concrete. This sustainable byproduct, recycled concrete aggregate (RCA), has the potential to replace natural aggregate. This paper examines the benefits of RAC from economic, social, environmental, and technological perspectives and discusses the replacement ratio (RR)—the weight percentage of natural aggregate replaced by recycled aggregate—which is crucial to RAC performance. A collection of used data on mechanical properties and economic performance, national specifications, standards, and guidelines is reviewed to determine the optimal replacement ratio for RCA, which was found to be 20%. Finally, we discuss the challenges and future of using RAC in structural concrete.

Eco-recycled cement's effect on the microstructure and hygroscopic behaviour of compressed stabilised earth blocks

Recycled cement (RCP) retrieved from old cement waste aims to replace carbon-intensive ordinary Portland cement (OPC) in earth stabilisation, improving the mechanical performance and durability of earth construction, without significantly compromising its ecological character and thermophysical properties. This study analyses the microstructure and hygroscopic behaviour of compressed earth blocks (CEB) stabilised with RC. In addition, soil was partially replaced with construction and demolition waste (CDW) to further improve the CEB sustainability. To this end, the sorption-desorption isothermal behaviour of CEB with different soils, types and contents of stabiliser (0–10 % RCP or OPC), and varying percentage replacements of OPC with RCP (20, 50, 100 %) or soil with CDW (0, 15, 25 %) was analysed and related to their microstructure, which was characterised in terms of scanning electron microscopy, mercury intrusion porosimetry and nitrogen adsorption analysis. Unstabilised and OPC CEB were considered for comparison purposes. The microstructure of CEB was refined after RCP stabilisation, which influenced their hygroscopicity and adsorption-desorption hysteresis. Depending on the clay content of the soil, stabilisation reduced or increased the hygroscopic capacity of CEB. After stabilisation, the water adsorption decreased up to 25 % in CEB with clayey soil and increased up to 22 % in CEB with sandy soil. However, the hygroscopic behaviour was not significantly affected by the type of stabiliser. The substitution of OPC with RCP increased the volume of water adsorption up to 3 %, due to its slightly finer porosity. RCP has proven to be effective as an earth stabiliser, leading to CEB with adsorption-desorption properties similar to those of OPC CEB.

The potential of processed mineral construction and demolition waste to increase the water capacity of urban tree substrates - A pilot scale study in Munich

Construction and demolition waste (CDW) represents one of the most significant waste streams worldwide. Due to a high brick content, CDW amended soil substrates are expected to improve water retention, benefitting urban trees.In this two-year field study evaluating the effects of CDW on the water holding capacities of urban tree substrates, six substrate mixtures are tested. Three test substrates contained a standard CDW mixture with 30 % and three 60 % bricks. Soil water contents were monitored and plant available water contents (PAWC) were analysed. From soil water contents and PAWC, the relative extractable water contents (REW), and subsequently the number of days with REW < 40 % and water stress intensity (WSI) are calculated.The substrates with enhanced brick content showed higher PAWC. However, the effect of brick on PAWC was only significant at a minimum of 30 % bricks in the substrate. Pore size distribution of the brick fraction confirmed the assumed relationship between addition of brick and increased PAWC. Substrates with an enhanced brick content showed reduced numbers of days with REW < 40 % and a reduction in WSI.Our findings demonstrate that CDW has potential to foster water holding capacities of urban tree substrates.

Mechanical properties and repairing mechanism of recycled cement stabilized macadam for road base based on microbial induced carbonate precipitation technology

The utilization of recycled coarse aggregate derived from construction and demolition waste (CDW) in the construction of road cement stabilized macadam base could effectively alleviate the shortage of natural sand and aggregate resources. To explore the repairing effect of microbial induced carbonate precipitation (MICP) on recycled cement stabilized macadam (RCSM), the physical, mechanical, and microscopic properties of recycled concrete aggregate under different precipitation precursor concentrations were researched in this paper. The mechanical properties of RCSM with varying contents of recycled concrete aggregate were analyzed before and after repairing. Based on scanning electron microscopy (SEM) and mercury intrusion porosimeter (MIP) tests, the microstructure and pore structure parameters of recycled concrete aggregate were explored, and the repair mechanism of MICP on RCSM was revealed via the performance analysis of recycled concrete aggregate and RCSM. The results show that MICP could effectively reduce the water absorption of recycled concrete aggregates, while simultaneously enhancing its apparent density and crushing resistance. In a certain range, the higher the concentration of the precipitation precursor, the better the repairing effect on the performances of recycled concrete aggregates. However, while the concentration of urea or calcium source concentration exceeding 1.0 mol/L, the activity of urease would start to be inhibited. The unconfined compressive strength of RCSM after MICP repairing could be increased by 22.7 % with a maximum extent compared with that before repair, while the maximum increase of indirect tension strength and flexural tensile strength was 15 % and 8.2 %, respectively. The biological CaCO3 generated by MICP reaction could fill the micro-cracks and pores of the recycled concrete aggregate efficaciously. Besides, it could also optimize the pore parameters and pore size distribution parameters, and enhance the adhesive strength of interfacial transition zone (ITZ) between cement and recycled concrete aggregates, which could improve the mechanical properties of RCSM.

Alternative concrete aggregates - Review of physical and mechanical properties and successful applications

Concrete is one of the most widely used construction materials, yet its production is associated with significant environmental impacts. One approach to mitigate such impacts is to use alternative aggregates. However, the limited knowledge about the availability and benefits of these unconventional materials, as well as concerns about their quality and performance, have hindered their adoption. This paper aims to analyse the potential benefits and limitations of using alternative aggregates in concrete by reviewing examples from three primary sources: construction and demolition waste (CDW), end-of-life materials (i.e., tyre rubber, glass, and plastic), and forest and agricultural waste (i.e., rice husk, wood, and hemp). First, the main sources and treatment needs are analysed. Then, a comprehensive macro analysis is provided on the physical and mechanical properties of concrete materials, discussing the results in terms of the aggregate nature and substitution ranges. The collected experimental data are also compared with estimations based on different models from two published codes, suggesting that more specific design-oriented models need to be developed to relate concrete's physical and mechanical properties using different waste-type aggregate replacements. Selected data analyses are presented to help the readers obtain the optimum content for specific structural or non-structural applications. Examples of successful application of alternative aggregates in construction projects and products are also provided and discussed.

Optimal supply chain performance: risk aversion to green innovation

PurposeAlthough many countries are focusing on the management of construction and demolition waste (CDW) resource utilization, the effect of risk aversion of the green innovation-led enterprise on the performance of the CDW resource utilization supply chain is unclear when considering different green innovation contexts (green innovation led by the building materials remanufacturer or by the construction waste recycler). This study aims to investigate how the level of risk aversion of the green innovation-led enterprise affects CDW resource utilization under different green innovation contexts based on contingency theory.Design/methodology/approachUsing Stackelberg game theory, this study establishes a decision model consisting of a building materials remanufacturer, construction waste recycler and CDW production unit and investigates how the level of risk aversion of the green innovation-led enterprise under different green innovation contexts influences the performance level of the supply chain.FindingsThe conclusions are as follows. (1) For the green innovation-led enterprise, the risk-averse behaviour is always detrimental to his own profits. (2) For the follower, the profits of the construction waste recycler are negatively correlated with the level of risk aversion of the green innovation-led enterprise in the case of a small green innovation investment coefficient. If the green innovation investment coefficient is high, the opposite result is obtained. (3) When the green innovation investment coefficient is low, the total supply chain profits decrease as the level of risk aversion of the green innovation-led enterprise increases. When the green innovation investment coefficient is high, total supply chain profit shows an inverted U-shaped trend with respect to the degree of risk aversion of the green innovation-led enterprise.Originality/value(1) This study is the first to construct a green innovation context led by different enterprises in the CDW resource utilization supply chain, which provides a new perspective on green management and operation. (2) This study is the first to explore the operation mechanism of the CDW resource utilization supply chain based on contingency theory, which provides new evidence from the CDW resource utilization supply chain to prove contingency theory. At the same time, this study examines the interactive effects of the green innovation cost coefficient and the degree of risk aversion of green innovation-led enterprises on the performance of supply chain members, expanding the contingency theory research on contingencies affecting enterprise performance. (3) This study will guide members of the CDW resource utilization supply chain to rationally face risks and achieve optimal supply chain performance.

Mechanical strength of an hot-mix asphalt using recycled concrete aggregate: mass and volume proportioning

The generation of solid waste produced by the construction sector is considered a major problem worldwide. Several studies have been conducted to evaluate the use of construction and demolition wastes (CDW) in pavements. Within CDW, one material with great potential for use is recycled concrete aggregate (RCA). The present study evaluated the mechanical performance of a hot-mix asphalt (HMA) that used RCA as a partial substitute for the coarse fraction of the natural aggregate – Nag (particle size retained on 1/2” and 1/2"+3/8” sieves). The substitution was performed in a conventional way by mass and also by volume. To evaluate the performance under monotonic loading, the stability/flow ratio (S/F) of the Marshall test and the Indirect Tensile Strength (ITS) were measured on dry (ITSd) and conditioned (immersed in water, ITSw) samples. The tensile strength ratio (TSR) was calculated to evaluate the resistance to moisture damage. Under cyclic loading, tests of resilient modulus – RM (three temperatures and three loading frequencies), permanent deformation, and fatigue resistance under controlled-stress were performed. Cantabro tests were performed to measure the resistance to abrasive wear. Conventional characterization tests and imaging processing in a scanning electron microscope (SEM) were carried out on particles of RCA and Nag. A Life Cycle Cost Analysis (LCCA) was performed with the results obtained. The general conclusions were as follows: (i) RCA increases the asphalt content in the mixes, however, volume substitution could help to decrease it; (ii) the mixes with RCA met the volumetric and strength parameters established by the Colombian specification (especially for roads with low traffic volumes); (iii) mixes with RCA undergo better mechanical performance in all tests performed, however, resistance to moisture damage may be compromised when dosing by volume and asphalt content decreases; (iv) substitution by mass or volume did not generate clear trends in the results, but better overall performance is reported in mixes dosed by volume. It is recommended to carry out more studies where Nag is replaced by RCA in volume.

Technosol made with urban and industrial waste: Potential for improving soil quality and growing tree seedlings

This study evaluated the use of waste materials to produce Technosol, a "tailor-made" soil consisting of construction and demolition waste (CDW), solid waste from stone mining (WSM), natural soil (NS), and compost from plant pruning (CPP), for improving soil quality in forest recovery projects. Samples of CDW were characterized using X-ray fluorescence and X-ray diffraction. The potential of the Technosol as a substrate was assessed using a mixture of "Class A" CDW, WSM, NS, and CPP in the following proportions: (a) 10 % CDW + 42.5 % WSM + 42.5 % NS + 5 % CPP, (b) 20 % CDW + 37.5 % WSM + 37.5 % NS + 5 % CPP, and (c) natural soil as a control. A randomized block design was used with nine treatments and three replications using 5.5 L pots. The experimental treatments consisted of two proportions of mixtures, natural soil, and three tree species: pioneer, Cecropia pachystachya, secondary, Handroanthus impetiginosus and climax, Copaifera langsdorffii. The activity of the enzymes β-glucosidase and arylsulfatase was determined in the Technosol and natural soil at the end of the experiment. During 180 days, the height of the plants and the diameter of the stem were determined at intervals of 30 days and, at the end of the experiment, the aerial part dry mass (leaves and trunk) and roots were evaluated. The Technosol constructed from the mixture (a) proved to be viable for improving soil quality, as indicated by a greater enzymatic activity compared to other soils, and for the growth of H. impetiginosus seedlings, showing the capacity to gain plant height over 180 days after planting.

Reuse of construction and demolition waste (CDW) fines as plant-growing substrate

Reuse of construction and demolition waste (CDW) fines as plant-growing substrate