Construction Disposal Research Articles

Experimental investigation of face mask fiber-reinforced fully recycled coarse aggregate concrete

To address the challenges associated with the disposal of construction and demolition waste (C&DW) and discarded personal protective equipment, this study investigates the feasibility of using face mask (FM) fibers to enhance fully recycled coarse aggregate (FRCA) concrete. The current study uses six FM fiber volume fractions (0, 0.1 %, 0.2 %, 0.3 %, 0.4 %, 0.5 %) for FRCA concrete reinforcement. According to the mechanical performance test results, adding FM fibers can enhance the splitting tensile strength (up to 8.22 % contents 0.1 % FM fiber) and flexural strength (up to 26.92 % contents 0.2 % FM fiber) of FRCA concrete. While excessive FM fibers (over 0.3 %) affect compressive strength negatively, the damaged concrete retains integrity due to the bridging action of FM fibers combined with scanning electron microscopy (SEM) analysis. Comparatively, the hydrophilic inner layer of disposable medical masks features a better microstructural fiber arrangement, increasing tensile strength by 14.51 % and 111.68 % compared to the filter and outer layers, respectively, making it ideal for enhancing FRCA concrete. All samples achieved a "Good" rating in the UPV tests, confirming the feasibility of FM fiber-reinforced FRCA concrete. The calculation method for FRCA concrete mechanical properties prediction considers the contribution of fibers in addressing the disparate effects of FM fiber incorporation, with correlation coefficients of 0.904 and 0.827 for splitting tensile strength and flexural strength, respectively. Environmental and economic impact analysis indicates that FM fiber-reinforced FRCA concrete can reduce carbon emissions by 71.25 % and save 29.05 % of economic costs.

Eco-friendly concrete: Combining treated wastewater and recycled aggregates.

The concrete industry is a significant consumer of drinking water and natural aggregates, such as sand and gravel. However, the scarcity of water and aggregate resources and the challenges associated with the disposal of construction and demolition waste prompted the exploration of alternative materials. This study investigates the feasibility of incorporating secondary treated wastewater from UASB reactors followed by trickling filters and mixed recycled aggregates as potential alternatives. To assess the viability of these alternatives, the study considered the replacement of 100% potable water with treated wastewater, as well as varying proportions of recycled gravel (20, 40, 60, 80, and 100%) and recycled sand (10, 20, 30, 40, and 100%). Physical and mechanical properties were negatively affected, but it was possible to reach compressive results over 40 MPa and splitting tensile strength over 4 MPa for almost all mixes. Regarding physical properties, the use of alternative materials caused poorer outcomes for density, water absorption, and air-void ratio. The limited magnitude of these detrimental effects indicates the potential of manufacturing concrete with the addition of combined treated wastewater and recycled aggregate as a viable strategy while enhancing reuse practices.

ENERGY SYSTEM DECARBONIZATION AND CIRCULAR ECONOMY: "BYPASS EMISSION HOTSPOTS"

For the first time, quantitative evidence has been obtained of the relationship between circular economy statistics and greenhouse gas emissions (GHG) from the energy sector. The developed approach makes it possible to find "hot spots of emissions" and visualize problem areas that impede the reduction of GHG. Correlation coefficients for GHG emissions/production, transmission, and distribution of electricity, and circular economy factors were calculated in accordance with this approach. It has been established that the disposal of construction and demolition waste is one of the main issues for EU countries, whereas municipal waste reuse and material reuse in energy production rank fairly well in 18 of the 27 EU countries.

Durability of concrete incorporating recycled coarse aggregates: carbonation and service life prediction under chloride-induced corrosion

The use of recycled aggregates (RA) is growing due to the environmental problems associated with extracting natural aggregates (NA) and the disposal of construction and demolition waste (CDW). However, the service-life prediction of recycled coarse aggregate concretes remains incipient. Thus, this study aimed to evaluate the effects of different replacement contents of NA by RA (25, 50, and 75 wt%) on physical (water absorption, porosity, and bulk density), mechanical properties (compressive strength and modulus of elasticity), microstructure (evaluated by X-ray microtomography), accelerated carbonation, and chloride penetration of concrete. A service life prediction analysis of RA concretes was conducted based on the chloride profile obtained and considering the application of different concrete surface treatments. The RA contents evaluated increased the carbonation and chloride diffusion coefficients by 75.7% and 43.0%, respectively, compared to the reference concrete. Nevertheless, reductions of approximately 50% on the critical chloride concentration depth of RA concretes are estimated considering the application of acrylic-based surface treatment. Therefore, applying surface treatments is promising to increase RA concretes' durability and service life, contributing to its wide use and dissemination feasibility.

Systematic comparison of different recycled fine aggregates from construction and demolition wastes in OPC concrete and PPC concrete

River sand is widely used as fine aggregates in concrete. Several countries have prohibited the use of river sand in construction owing to the devastating effects of excessive river sand mining. Hence, the need for alternative fine aggregates is substantially enhanced in the construction sector. The disposal of construction and demolition wastes into landfills is a major concern due to the stringent environmental regulations. Using recycled fine aggregates from construction and demolition wastes as alternative fine aggregates is an environmentally viable solution for excessive river sand mining. Although numerous previous studies on recycled fine aggregates are available, a comprehensive review of the comparative assessment of different recycled aggregates derived from construction and demolition wastes is highly limited. Therefore, the potential reuse of various types of recycled fine aggregates from construction and demolition wastes such as concrete, brick, ceramic and marble wastes as fine aggregates in ordinary concrete and PPC concrete is presented in the review. The influence of recycled fine aggregates on fresh properties such as workability, air content and density is presented. Besides, compressive strength, tensile strength, flexural strength, water absorption, carbonation and shrinkage of recycled fine aggregates used in ordinary concrete and PPC concrete are methodically compared. High water absorption of the recycled fine aggregates lowers the workability of concrete. Reduction in the density of concrete is observed due to the increased porosity while replacing river sand with recycled fine aggregates. Increase in the carbonation depth, air content and shrinkage are witnessed for all types of recycled fine aggregates incorporated concretes.

Construction and Destruction Waste Management Practices to Reduce Environmental Impact in Bangladesh

Bangladesh is a fast-growing developing country and Buildings of Mymensingh city areas are increasing rapidly in last five years. The management of construction and demolition trash is an issue given the dramatic increase in 20-building construction. Environmental contamination has risen recently due to a lot of development and demolition trash. Building materials, collection techniques, recycling and disposal should all be evaluated to assess this problem. This article demonstrates the Reuse, Recycling and Disposal of Construction and Demolition waste as a way for environmental protection, and Construction and Demolition waste management. The investigation was based on field visits, interviews, secondary data sources, and conceptual methods. We surveyed 300 construction sites (buildings) in Mymensingh city as a new city corporation of the country. We found 31% materials are reused, 26% are recycled and rest of the materials is nominated as construction waste. This paper also examines the management practices for evaluating the result. Different methods could be used to reduce waste and increase profits through recovery, reuse, and recycling of construction and demolition waste. For proper reuse and recycling of Construction and Demolition waste, waste management strategies, reliable and tested case studies are necessary.

Life cycle assessment of three typical recycled products from construction and demolition waste

Environmental issues caused by the disposal of construction and demolition waste (CDW) is a worldwide problem. However, current studies lack a unified assessment of the reuse of CDW for quantifying the benefits in terms of the environment, economy, and carbon emissions. This study conducts a life cycle assessment on three typical recycled products manufactured from CDW: masonry bricks, permeable bricks, and thermal insulation blocks. The functional unit is 1 ton of CDW utilisation, and the system boundary is “cradle to gate”. The results indicate that the freshwater ecotoxicity, marine ecotoxicity, human carcinogenic toxicity, and human non-carcinogenic toxicity are the key categories of environmental impact. The mixing process is the key impact process, which accounts for more than 70% of each key environmental impact category. The cement and adhesive glue are the key impact materials. When considering the benefits of construction waste replacing traditional building materials, CDW recycled products can achieve significant environmental benefits and carbon reduction effects, which is decreased by at least 1.3 of normalised environmental impact and 15.6 kg CO2e under per functional unit.

Estimated cost of transporting construction and demolition waste in Recife, Pernambuco, Brazil

The construction sector has grown significantly in the last decade, also expanding the environmental damage inherent to the activity, especially the production of solid waste, with an annual estimate of over 760,000 tons for the municipality of Recife. Proper disposal of construction and demolition waste (RCD) should be technically and economically feasible, where the collection and disposal process results in an additional cost for any building work, and transportation is a relevant stage of this, where its value is determined by variables such as distance, traffic and access road conditions. This study aims to analyze the variation in the cost of transportation of RCD in Recife, starting with a survey of the destination points on the CPRH page, delimiting three coverage areas, and calculating the minimum mean transport distances (DMT). and maximum in the demarcated regions, being observed the variations of the DMTs in each area, through the Tukey test. As a price reference, the SINAPI table was used, calculating the minimum and maximum costs for each area. Finally, a considerable variation in the minimum cost was observed in one of the areas, while no relevant disparities in the maximum price were detected.

Effect of lime filler on RCA incorporated bituminous mixture

The use of Recycled concrete aggregate (RCA) obtained from construction and demolition waste not only reduces the need for virgin aggregates but also solves the problems associated with the disposal of construction and demolition (C&D) waste. Despite being a promising prospect, field utilization of RCA in bituminous mixes is limited due to the problems like lower strength and higher moisture susceptibility. To solve these issues present study aims at examining the effect of lime filler on RCA incorporated bituminous mixes. In the present study, RCA was obtained by mechanically treating C&D waste in a Los Angeles abrasion machine. Bituminous mixes were prepared by using 10%–50% of RCA. Additionally, 2% lime was added to the RCA incorporated mixes, and the parameter like optimum bitumen content, Marshall stability, Marshall quotient, Indirect tensile strength, Retained Marshall stability and Tensile strength Ratio were compared with the control mix to examine the effect of RCA and lime on mix properties. The inclusion of RCA was found to adversely affecting the properties of the mix whereas the inclusion of lime improved the properties. To provide a clear understanding of the environmental and economic benefits of utilizing RCA in bituminous mixes, economic and environmental assessment was also done. Based on different test results and analysis it was concluded that with the use of lime fillers it is possible to produce economical and environmentally friendly RCA incorporated bituminous mixes having properties comparable/better than conventional hot mix asphalt (HMA).

Geographic Information Systems supported by multi-criteria decision analysis to indicate potentially suitable areas for construction and demolition waste disposal

In Brazil, the disposal of construction and demolition waste (CDW) quite often occurs in inadequate places, resulting in social, economic, and environmental problems. This reflects the need for selecting appropriate areas for the disposal of this type of waste. These areas must follow local standards and regulations to protect human health and the environment. Considering that, this study is intended to indicate potentially suitable areas for CDW landfill deployment, known as Class A landfill in Brazil, supported by a GIS-MCDA based model. The GIS-MCDA technique, used as a basic tool to identify potentially suitable areas, has several advantages, such as low cost, reduced spatial data subjectivity, and fast decision-making process. The place chosen for this study is the Urban Central Core of the Metropolitan Area of Curitiba. By integrating GIS with MCDA techniques in this research study, it was possible to indicate potentially suitable areas for CDW disposal in this region.

Demolished building waste management: a review

Construction and demolition waste are the major issue as a direct consequence of increased global urbanization. It impacts the environmental efficiency of the construction industry, contributing to 35% of the global landfill. This research considers the two main fundamental factors affecting the demolished building waste management, which are the management hierarchy including the 3R strategies and the project life cycle and management tools. The inappropriate treatment and disposal of Construction and demolition waste give rise to the environmental pollution, land price, and natural resource consumption. This paper scrutinizes the concept of Construction and demolition waste management and review the extant studies in the managerial areas of Construction and demolition waste. These findings are aimed at clarifying the current and future practices of Construction and demolition waste management practices with an understanding for the sustainable governance.
 Keywords: Construction and demolition waste, management, review.

Mechanical Properties of Concrete Using Recycled Aggregates Obtained from Old Paving Stones

Nowadays, construction, maintenance, reparation, rehabilitation, retrofitting, and demolition from infrastructure and buildings generate large amounts of urban waste, which usually are inadequately disposed due to high costs and technical limitations. On the other hand, the increasing demand for natural aggregates for concrete production seriously affects mountains and rivers as they are the source of these nonrenewable goods. Consequently, the recycling of aggregates for concrete is gaining attention worldwide as an alternative to reduce the environmental impacts caused by the extraction of nonrenewable goods and disposal of construction and demolition waste (C&DW). Therefore, this article describes the effect on the mechanical properties of new concrete using recycled aggregates obtained from old paving stones. Results show that replacing 50% by weight of the fine and coarse aggregate fractions in concrete with recycled aggregate does not meaningfully affect its mechanical behavior, making the use of recycled aggregates in new precast paving stones possible. Therefore, the latter can reduce environmental impacts and costs for developing infrastructure and building projects.

Effect of pozzolan slurries on recycled aggregate concrete: Mechanical and durability performance

Disposal of construction and demolition wastes (C&DW) has been deemed as a major concern all over the world due to their disposal crisis that often adversely affect the environment. Several efforts are being made to recycle and manage such wastes for using them in the different building materials production. Using recycled concrete aggregate (RCA) as a partial or full substitution for normal aggregate (NA) in cement concrete is becoming a desirable solution to handle the huge amount of (C&DW). However, RCA possesses relatively higher porosity due to the adhered mortar, which often impedes its application in the construction industries. This paper proposes an economic and environmental approach to optimize the recycled aggregate concrete (RAC) performance. Outcomes showed that the modified RAC exhibited better mechanical strength and higher chloride ion migration resistance than untreated RAC. Compared with normal concrete (NAC), the loss in compressive strength was between 4.5 and 18%, flexural strength 3–18.5%, and elastic modulus 8–22% for the modified RAC at 28-days age. The numerical simulation model to analyze the chloride migration process for the treated RAC showed a good convention with the experimental test results. X-μCT images demonstrated that the untreated RCA sample has larger pores and air voids than the treated RCA samples. The proposed strengthening technique improved the micro-structure of the ITZ for RAC, making it denser and reduced the micro-cracks when compared with the untreated RAC. This technique provides the possibility to use 100% RCA in concrete and address the long-term environmental, waste disposal, and economic goals.

BIM-based information system for econo-enviro-friendly end-of-life disposal of construction and demolition waste

Increasing quantities of Construction and Demolition Waste (CDW) have caused serious resource shortages and environmental damage, resulting in the requirements of scientific disposal technologies and methods. In this study, based on the 3R principle, a Building Information Modeling (BIM)-based CDW information system is established using Revit software to reduce the CDW, which overcomes the obstacles of BIM adoption and displays information directly related to CDW. A Reverse Logistics (RL) network is then proposed to regulate the end-of-life disposal of CDW, after which mathematical formulas are introduced to calculate the disposal costs and carbon emissions, to achieve environmental and economic balance. The results showed that the methodology was successfully applied, with precise CDW information obtained for the disposal cost and emission estimations, and high recovery of CDW was guaranteed to achieve sustainable waste development. Efforts can be made on CDW 3D visualization interfaces and the social benefits consideration in future research.

Effect of Crushed Glass on Behavior of Crushed Recycled Pavement Materials Together with Crumb Rubber for Making a Clean Green Base and Subbase

AbstractOne of the most destructive environmental issues around the world is the disposal of construction and demolition (C&D) wastes such as recycled concrete aggregate (RCA), crushed rock (CR), w...

Influence of fluidity on mechanical and permeation performances of recycled aggregate mortar

Abstract The use of recycled fine aggregates in making mortar is an effective measure to increase the social and ecological values these days due to the pressing issues associated with the over-exploitation of natural sand as well as disposal of construction and demolition wastes. To counteract the synergetic effects of W/C ratio, recycled fine aggregates quality and its content, fluidity was considered as parameter to formulate the recycled aggregate mortar. The experimental results of this investigation elucidate the effectiveness of fluidity on mechanical and permeation performances of recycled aggregate mortar. A comparison with the outcomes of conventional mortar is also presented. The experimental outcomes reveal that, recycled aggregate mortar requires additional amount of water to attain the same fluidity of controlled mortar due to inferior characteristics of RFA, such as high initial water absorption and volume of voids with in mortar. The setting characteristics of recycled aggregate mortar were influenced by the fluidity, recycled fine aggregates quality and its content and their setting times were earlier than that of controlled mortar. However, recycled aggregate mortar corresponding to the fluidity of 110 ± 2.5 mm and 160 ± 2.5 mm attained lower strength characteristics, lower pulse velocity value, higher permeable void content, higher water absorption by immersion and higher sorptivity than those associated to the fluidity of 135 ± 2.5 mm. Therefore, recycled aggregate mortar associated to the moderate fluidity of 135 ± 2.5 mm is feasible and exhibits better mechanical and permeation performances.

Long-Term Performance Evaluation of Concrete Pavements Containing Recycled Concrete Aggregate in Oklahoma

To overcome the challenges associated with natural aggregate shortage and the disposal of construction and demolition waste, recycled concrete aggregate (RCA) has been increasingly used in Portland cement concrete (PCC) pavement as a virgin aggregate replacement. The work in this study involved conducting a performance evaluation of the existing RCA-PCC pavements in Oklahoma from different aspects, including: laboratory determination of mechanical properties; a petrographic examination of the concrete; a field evaluation using a falling weight deflectometer (FWD) testing; and distress surveys to assess pavement behavior. The laboratory testing of the field cores confirmed that the addition of RCA into PCC causes a reduction in the modulus of elasticity and tensile strength; the reclaimed mortar was found to be the primary weak zone through which cracks pass. The surface condition survey data and analysis of the FWD results match each other, indicating that the RCA joined plain concrete pavement (JPCP) section exhibited lower performance compared with the control JPCP section. But this trend was not as definitive for continuously reinforced concrete pavement (CRCP). The relatively good performance of the RCA CRCP results from the section being rested on a stronger asphalt concrete base layer. Additionally, the inherent stiffness fundamental to the behavior of CRCP provides a superior level of protection of the base from erosion damage compared with a jointed pavement. The findings indicate that erosion-resistant base support and good load transfer are essential design considerations for JPCP made of RCA-PCC. CRCP appears to be more suitable for the use of RCA-PCC.

Developing an RFID-based tracking system to improve the control of construction surplus soil disposal in Taiwan

ABSTRACTThe current tracking system for construction surplus disposal soil report system (CSRS) in Taiwan is labor-intensive and prone to human error, with its accuracy and effectiveness often questioned. Radio-frequency identification (RFID) is a wireless sensing technology that uses radio waves and signals to wirelessly transmit, retrieve, and store data to identify the status of objects and contents. It can be read at long ranges and be operated in extreme environments. This paper has improved the existing construction surplus soil tracking system by developing an integrated RFID-based tracking system (RFID-CSRS). To accommodate the characteristics of the domain problems, RFID-CSRS integrates RFID technology with Internet infrastructure, cameras, and signal controlling units. The proposed system reduces human errors, such as incorrect manual recording and identification, inaccurate monthly reports and audits, and improper picture-taking of trucks. RFID-CSRS was also assembled and tested in two surplus soil disposal cases in Taiwan. The results demonstrated the soundness of the system and its capability to improve the effectiveness of the current system in tracking the disposal of construction surplus soil.

Organizational and technological cycle of life of a construction object

During the life cycle, the state of an object is modified. The information for stepwise and phased study of innovation processes is characterized as local and torn in time, while the life cycle approach regards the process of creating and developing technological innovations as a dynamically synchronized system. The development of organizational and technological systems is being implemented in two directions: the improvement of basic and the creation of fundamentally new technologies. The life cycles of all objects, processes and systems are built on one info graphic model: any life cycle begins with the birth, passes through the stages of growth, maturity, decay and decline. Therefore, it is advisable to consider the innovative investment and construction life cycle of an object as a combination of a series of successive stages (cycles). They are sub-cycles during the period from the beginning of the idea of the initial design and construction of an object until the demolition, complete disassembly, disposal of construction and demolition waste (CDW) and non-recyclable parts of them.

Co-benefits of urban concrete recycling on the mitigation of greenhouse gas emissions and land use change: A case in Chongqing metropolis, China

Rapid urbanization drives massive construction, which, in return, leads to ever increasing urban metabolism challenges on the provision of raw materials, as well as the disposal of construction and demolition waste. Due to its large volume, the transporting and processing of these materials cause considerable greenhouse gas emissions and land use change. With this circumstance, shortening the supply chains of urban construction by efficient recycling of construction and demolition waste becomes a frontier field for the circular transition of cities. It is particularly important in current China, where the concrete recycling is still rare. This paper aims to map the opportunities and potentials of concrete recycling on the mitigation of greenhouse gas emissions and land use change, with an integrated material flow analysis and life cycle assessment for the case study city – Chongqing, China. For the baseline year 2015, four scenarios representing various recycling routes in Chongqing have been explored: (1) improving brick manufacturing; (2) recycling on-site for road base filling; (3) recycling aggregate for prefabricated concrete component and (4) recycling concrete aggregate for structure use. Results highlighted that different technological routes have different potentials to increase recycling rates but all generate co-benefits on greenhouse gases mitigation and land transformation reduction. Recycling of stony construction and demolition waste for high value concrete aggregate has the biggest potential to bring the co-benefits on greenhouse gases mitigation and land use reduction. Besides, on-site recycling for road-base aggregates also presents a high performance, especially on greenhouse gases mitigation in transport. Based on the sensitivity analysis, policy implications were discussed, highlighting the necessity of to develop the recycling routes that substitute primary gravel with aggregates recycled from the stony waste; unlocking the existing recycling capacity and restricting landfilling.