Construction Demolition Waste Research Articles

A new experimental approach to the improvement of sandy soils with construction demolition waste and cement

Soil improvement has become an important issue on which further investigations should have to be performed in depth as a result of an increasing demand rate on land use in order to compensate increasing population. The main reasons for soil improvement are to decrease plasticity, reduce permeability and compressibility and increase soil strength. Wastes can be used along with some other additive materials such as cement, lime, fly ash, and bitumen in the improvement of soils which are inadequate in terms of engineering properties. In recent years, as a result of increasing rates of earthquakes along with the numbers of constructions which are to be demolished as the updated regulations point out, a great amount of wastes have been accumulating. These wastes are generally referred to as construction demolition wastes (CDW). There exist some methods which are considered for the elimination of these wastes. One of the mentioned methods is to use construction demolition wastes in soil improvement procedures. Within the context of this study, effects of construction demolition wastes (CDW) and cement (CMT) on soil stabilization and engineering properties of sandy soils (SS) were investigated. Parameters such as optimum ratios of CDW and CMT, bearing capacity and settlement values, soil improvement depths, and time factor were analyzed. Consequently, an equation with high-degree correlations was obtained in order to use CDW and CMT efficiently at optimum ratios. It was determined that by using CDW, increments of up to 3.09 times were attained in the values of bearing capacities. The optimum value of improvement depth for sandy soil was obtained as H/D = 0.75 (H: soil improvement depth, D: diameter of the model footing) up to a pressure value of 520 kPa. It was also found that the highest bearing capacity with respect to time was reached at the end of 28 days and a significant increment did not take place in the values of bearing capacities after exceeding the mentioned time period. Therefore, it is proposed that at least 28 days should pass after the completion of any soil improvement procedure before any further construction work is initiated.

The Utilization of Recycled Aggregate in High Performance Concrete: A Review

This paper reviews the use of Recycled Aggregate (RA) that is collected from construction demolition waste in the production of concrete. The paper primarily focuses on the possibility of using RA in High Performance Concrete (HPC). By analytically reviewing previous work, this study reports the mechanical and physical properties of HPC prepared using RA. The study summarizes the results of workability, water absorption, dry density, compressive strength, tensile strength, and flexural strength of HPC prepared with RA as reported in previous works. The paper also addresses the microstructure and durability performance of this concrete. Using RA in concrete production is an environmentally friendly solution to the continuous depletion of natural aggregates. RA could improve the cement matrix mechanical properties. Due to the porosity of RA, they have lower unit weigh than natural aggregates. For the same reason, RA can significantly decrease the workability of concrete. It is reported that using RA increases compressive strength of HPC. Both splitting and flexural strengths are increased with RA, however, they are decreased when the ratios of replacement are increased. The use of RA in the production of HPC seems to be promising. This paper presents some recommendations to further study this topic.

Sustainable management and technologies for recycled construction demolition waste in Vietnam

This study introduces the series of activities and results that are contributing for the CDW recycling industry in Vietnam especially for the implementation of the recently introduced Circular No.08/2017/TT-BXD. The equation for estimation of the amount of CDW generated from building demolition was introduced. New management regulations which are guideline for demolition, sorting, transportation and treatment and new Vietnamese standard for specification of testing and acceptance for CDW recycling materials are highlighted. The properties of recycling concrete from a pilot project were tested. The research designed a circle of recycling business that results from research are contributing for the sustainable management and technologies in Vietnam. These activities and contributions will significantly support for the implementation of Government’s new regulation, reducing the solid waste to meet the National strategies for environment as well as open for a new important recycling industry in Vietnam.

Strength and Drainage Characteristics of Poor Soils Stabilized with Construction Demolition Waste

This paper presents a laboratory investigation on the use of construction demolition waste in poor clayey soil to improve its strength and drainage characteristics. Various laboratory tests such as differential free swell, Atterberg’s limits, compaction, unconfined compressive strength (UCS), California bearing ratio (CBR), and permeability have been conducted on un-stabilized and Construction Demolition Waste (CDW) stabilized clayey soil. The outcomes revealed that the addition of CDW in poor soil reduced both maximum dry density and optimum moisture content. The UCS, CBR, and permeability got improved on adding optimum content of CDW in poor clayey soil. The secant modulus also increased on addition of the CDW in virgin soil. The regression analysis performed for different tests showed good agreement of laboratory results with predicted values. Thus, it can be revealed that using CDW in stabilization of poor clayey soil will not only solve the problem of its disposal but will also be cost effective and protect the environment.

Mechanical Properties of High Calcium Flyash- GGBFS Geopolymer Paste, Mortar and the Effect of Glass Fibre Mesh on the Strength of Geopolymer Mortar Tile

In this paper, a combination of high-calcium fly ash (HCFA) and ground granulated blast furnace slag (GGBFS) was used along with a combination of sodium hydroxide (NaOH) and sodium silicate(Na2SiO3) as alkaline activators (AAs) to produce geopolymer paste and mortar. The alkaline activator ratio (AAR) was maintained at 1.5 apart from their molarity at 10 for the study. A rational method, namely minimum voids approach was used for the mix design. A commercially available glass fibre mesh was used as reinforcement in the geopolymer mortar produced above, to assess its potential for use as a flooring tile. The influence of W/S (water-to-solids) ratio and the influence of various fine aggregates, namely, river sand (R), manufactured sand (M) and construction demolition waste (D) on the various geopolymer system (GP) and on the strength characteristics, are highlighted. A maximum transverse strength (TS) of 6.25 N/mm2 could be attained by the geopolymer tile, using three layers of glass fibre mesh and GP mortar developed. The study indicates that a combination of FA and GGBFS helps us to attain substantial strength under ambient temperature in geopolymer mortar.

Replacement of fine aggregate by using construction demolition waste steel powder in concrete

This paper aims to study experimentally, the effect of partial replacement of fine aggregates by steel powder on the various using slump strength and durability properties of concrete, by using the mix design of M20 grade. The optimum percentage of replacement of fine aggregate by steel powder is found. Workability of concrete gradually decreases, as the percentage of replacement increases, which is found test. Compressive strength, tensile strength, flexural strength and durability tests. The results indicate that for conventional concrete, the partial replacement of fine aggregates by steel powder improves the compressive, tensile and flexural strength. The mass loss in cubes after immersion in acids is found to be very low. Deflection in the RCC beams gradually increases, as the load on the beam increases, for both the replacements.

ANÁLISE DA CORRELAÇÃO DO VOLUME DE RESÍDUOS SÓLIDOS PROVENIENTES DA CONSTRUÇÃO CIVIL COM O PRODUTO INTERNO BRUTO PARA OS MUNICÍPIOS NO ESTADO DE MINAS GERAIS

O provimento de informações bem como a gestão de resíduos da construção civil (RCC) ainda é um desafio no Brasil e em Minas Gerais. O presente artigo aborda o universo da construção civil e o volume de resíduos gerados proveniente de sua atividade, e identifica se existe correlação entre o Produto Interno Bruto (PIB) e a quantidade de resíduos provenientes da construção civil (RCC) em municípios de Minas Gerais, bem como avalia se essa correlação é influenciada pelo tamanho da população. Para atingir os objetivos são utilizados dados do Sistema Nacional de Informações sobre Saneamento (SNIS) para informações sobre coleta de RCC e do PIB e população produzido pelo Instituto Brasileiro de Geografia e Estatística (IBGE). Os dados levantados estão organizados em quatro grupos conforme população, e para os municípios que não informaram o volume de RCC foram desconsiderados da série histórica. Na sequência é avaliada a correlação entre a geração de resíduos e o produto interno bruto por meio de teste estatístico de correlação pela metodologia de Pearson. Os resultados demonstraram uma correlação fraca entre o PIB e a geração de RCC para municípios até 50 mil habitantes e moderada para aqueles superiores a essa população. Quando considerados os valores médios por faixa populacional delimitada no presente estudo a correlação obtida foi muito forte.

Structural Behaviour Fly ash and Ferrochrome ash Based Geopolymer Concrete with Recycled Aggregate

Recycled aggregates are the construction demolition wastes which can be used in concrete industry to reduce the carbon footprint of the environment. This paper deals with the structural behaviour of reinforced concrete beam made with different percentages of recycled aggregate as coarse aggregate on a novel geopolymer concrete consist of fly ash and ferrochrome ash as binder. Structural behaviour of RCC beam with 10% and 20% recycled aggregate in geopolymer concrete are studied and compared to the 100% natural coarse aggregate. Experimental results revealed that the up to 10% replacement of recycled aggregate can achieve strength equal to control concrete and it can be the recommended percentage of RCA for concrete industry.

Mechanical Properties of Fly Ash Based Concrete Aided With Recycled Aggregates and Manufactured Sand

Enhancement of concrete strength to shoot the need, demand and to make sustainable is being studied by bountiful researchers across the globe. Utilization of industrial waste and construction waste is an area being explored in the recent days properties of construction demolition waste is unique in nature and result of one research will not maintain with other due to heterogeneous nature of demolition waste. In this work a special type of demolition waste is obtained from building is utilized in concrete in tandem with fly ash instead of sand cost effective and sustainable mixed sand is used in this study in varying proportions. Four different mixes (M1 M2 M3 M4) is prepared using standard sampling procedures and tested for strength and durability. It is found that M2 shows considerable strength in with increasing curing period and it can be selected as optimum mixture. Graded mixed sand used in this study shows considerable increase in strength in coordination with recycled coarse aggregates.

Investigation of spatial stratified heterogeneity of cemented paste backfill characteristics in construction demolition waste recycled aggregates

This paper discusses the application of construction demolition waste (CDW) in the field of backfill mining as an efficient way of increasing the CDW utilization rate. But much of the research on cemented paste backfill (CPB) with the CDW has been conducted in the laboratory which cannot accurately explain the spatial differentiation characteristics and mechanism of onsite CPB. To this end, this study uses fractal theory, image processing, and scanning electron microscopy (SEM) to analyze the spatial stratified heterogeneity (SSH) of recycled aggregates and the mechanical properties of the CPB under the natural flow of slurry. The spatial distribution mechanism of the CPB’s performances is also explained. The results indicate that the compressive strength reaches a maximum of 4.07 MPa on the top of the upper segment and a minimum of 1.6 MPa on the bottom of the upper segment, with a mean value of 2.4 MPa in the whole tunnel. This satisfies the requirements of field applications. The maximum and minimum mean particle sizes appear on the bottom of the upper segment and the lower segments of the tunnel, and the multifractal parameters are shown to indirectly reflect the distribution of recycled aggregate size. According to the test results of sampling point, the spatial distribution of CPB’s strength and recycled aggregate along the flow direction of slurry are regressed, allowing the tunnel to be divided into five distinct regions. Finally, the PSD of recycled aggregates and microstructures has a profound impact on the mechanical properties of CPB, but the motion characteristics of the recycled aggregates are the main reason for the SSH of the CPB properties.

Behaviour of recycled aggregates RC columns strengthened with CFRP under uniaxial compressive loadings

The recent development in the construction industry has significantly influenced the socio-economic growth and the built environment of the mega cities around the globe. However, these developments have also resulted in millions of tonnes of construction demolition waste, which is mainly dumped, in the already populated landfills. As a result, the construction waste is not only causing a threat to the natural resources but also to the already deteriorating environment. Over recent past, studies have been conducted which investigated the use of concrete based construction waste as recycled coarse aggregates in preparing concrete for structural purposes. Based on these studies, in general it was found that the concrete compressive strength decreases with the increase in the percentage of recycled aggregates. Furthermore, studies have also been carried out in which use of Carbon Fiber Polymers wrapped along the outer surfaces of the structural elements resulted in significant increase of load carrying capacity. Therefore, in this study, investigation aims at the behaviour of reinforced concrete columns made with recycled aggregates and wrapped with Carbon Fiber Reinforced Polymers under uniaxial static compressive loading. For this purpose, 12 rectangular specimens having cross section dimensions of 150mm x 300mm and height of 600mm reinforced both longitudinally and transversely were used. The specimens were made with three different mixes of concrete having 0%, 30% and 50% of recycled aggregates. It was found that the recycled aggregates reinforced concrete specimens wrapped with CFRP exhibited higher compressive loads as compared to their corresponding specimens made with natural aggregates.

Investigation of the Effect of Curing on Improvement of Uniaxial Compressive Strength Properties by Construction Demolition Waste

Investigation of the Effect of Curing on Improvement of Uniaxial Compressive Strength Properties by Construction Demolition Waste

Effect of addition of construction–demolition waste on strength characteristics of high plastic clays

Various wastes have gained attention nowaday as they are widely used in stabilization of expansive soils. The construction–demolition waste has not been widely used in soil stabilization, and its use is still under research. A lot of construction–demolition waste is being produced from old dismantled buildings whose disposal is a major concern due to limited availability of land space. This paper presents a laboratory investigation using consolidated drained triaxial test in order to study the stress–strain and volumetric behavior, shear strength parameters, strength ratio at various strain levels and stiffness of un-stabilized as well as crushed construction–demolition waste (CCDW) stabilized soil. The test results revealed that the addition of CCDW in un-stabilized soil has improved its stress–strain and volumetric behavior remarkably, at all confining pressures. The volumetric strain has been found to be decreased with the addition of CCDW. The inclusion of CCDW in un-stabilized soil has decreased the cohesion value to a limited extent and increased the angle of shearing resistance significantly. An increase in strength ratio as well as the stiffness of un-stabilized soil has also been improved when it is stabilized with CCDW. In the end, a practical numerical example has been solved in order to make the readers understand the significance of the improvement in un-stabilized soil after incorporating CCDW into it. This mixture of CCDW-stabilized expansive soil can be used in construction of low-volume traffic roads and embankment stability.

An experimental study on uplift behaviour of granular anchor pile in stabilized expansive soil

ABSTRACT This paper presents the results of laboratory investigation on model granular anchor pile (GAP) installed in poor clayey soil in terms of their response against pullout forces by varying pile length, diameter, and relative density (RD) of granular material. The laboratory testing was performed for un-reinforced/ reinforced GAP installed in un-stabilized/stabilized soil. The experimental study revealed that increasing the length and diameter of GAP increased the ultimate pullout load for all the cases. The un-reinforced GAP installed in crushed construction demolition waste (CCDW) stabilized soil and geogrid reinforced GAP installed in un-stabilized soil showed improved values of ultimate pullout loads as compared to un-reinforced GAP installed in un-stabilized soil. Further, the ultimate load carried by un-reinforced GAP installed in stabilized and reinforced GAP installed in un-stabilized soil is approximately constant. Increasing RD of granular material enhanced the ultimate pullout load for all cases.

Feasible Construction Applications for Different Sizes of Recycled Construction Demolition Wastes

Although construction and demolition wastes (CDW) has been recycled widely in many industrial countries, such application is still limited in many under development countries. Efficient recycling and more possible applications for different parts of the crushed CDW materials provided more added values to these environmentally harmful wastes and hence encourage their recycling efforts. The main objective of this study is to propose sustainable construction utilizations of common CDW materials usually found in developing countries. The influence of two different crushing techniques, on various particles size’s properties of the recycled CDW samples, was investigated. In addition, performance of some construction materials, made of different particle sizes of the recycled CDW, was studied. Coarse particles of crushed CDW were used as coarse aggregates for concrete and the fine particles were proposed for producing cement bricks. On the other hand, very fine particles were assessed as pozzolanic materials or as mineral filers for asphalt. Jaw technique was found more efficient, to recycle the investigated CDW materials, than hammer technique. On the other hand, proposed optimum construction applications, for different particle sizes of the recycled materials, were ranked based on the performance of the proposed construction materials.

Recycling phosphogypsum and construction demolition waste for cemented paste backfill and its environmental impact

Abstract Solid waste management has become an important global issue, and the collection, recycling, and disposal of solid waste have great environmental impacts. This study investigates the feasibility of recycling two different solid wastes, phosphogypsum (PG) and construction demolition waste (CDW), as cemented paste backfill (CPB). The properties of the CPB were first demonstrated through a slump test, setting time detection and unconfined compressive strength (UCS) tests, and microstructural analysis. The environmental impact of the PG and CDW-based CPB was investigated through a static leaching experiment, a rotary acid leaching procedure, and index detection. A novel backfill system and process was also developed for engineering applications. The results show that (1) the solid concentration of CPB increased from 60 wt% to 70 wt% and the initial/final setting time decreased to 20–30% with the addition of CDW (from 0 wt% to 40 wt%); (2) the UCS of the CPB samples after 28 days of curing reached 1.74 MPa at 40 wt% CDW proportion, a cement/sand ratio of 1:6, and 70 wt% solid concentration; (3) the CPB samples had a high residual strength (80% of the UCS), indicating d and CDW-based CPB can support an underground stope after failure; and (4) the environmental indices for the bleed water and leachates of CPB satisfied the category III requirements of China's environmental standard (DZ/T 0290-2015). The results suggest that the proposed technology is a reliable and environmentally friendly alternative for recycling PG and CDW while simultaneously supporting safe mining.

Concrete recycling life cycle flows and performance from construction and demolition waste in Hanoi

As construction increases through a rise in development in Vietnam, the environmental performance of recycling construction and demolition waste is not well documented. This paper addresses this lack of knowledge, by mapping the current recycling system and estimating recycling performance of a key component in construction and demolition waste in Vietnam, concrete. Primary data were collected directly from six Vietnamese construction enterprises involved in the life cycle of construction and demolition waste management. The results indicated that potential net environmental benefits exist for all impact categories examined if a mechanised plant were considered. Moreover, construction demolition waste may then be used for more permanent applications such as building foundations and in new building materials. The results confirm benefits to technological advancements in concrete recycling in the construction demolition waste sector. Fostering investment and interest in such strategies could be achieved by imposing clear and consistent construction demolition waste classifications, establishing clear lines of responsibility, and coordinating activities amongst key stakeholders to promote the benefits of concrete recycling. These findings consolidate the need of further research in Vietnam and other developing nations, where more detailed life cycle inventory development and stakeholder engagement could help. Then better environmental outcomes through the concrete recycling management may be delivered.

Valorization of Building Retrofitting Waste as Alternative Materials in Gypsums

Introduction:The lack of treatment of construction demolition waste (CDW) is a problem that must be solved immediately. It is estimated that the unused CDW generates an increase in the use of new materials close to 20% of the total materials consumed worldwide. Because of that, the use of CDW in building materials is an interesting alternative to guarantee their application. In the last years, many research works are being carried out in order to analyze the viability of using CDW as a substitute for the traditional raw materials that cause high environmental impact.However, much remains to be done, because these works generally characterize materials but not specific applications that allow the agents of construction to provide assurance required by the projects.Aim:The research group TEMA from the School of Building Construction (UPM) is working on this topic with the University of Seville, University of Burgos and the University of Zaragoza, developing a research project called "Waste to resources (W2R)". The main goal of the project is to develop new materials, elements and construction systems, manufactured with CDW generated in building retrofitting works, to be used in improving the energy efficiency of buildings.Results:In this article, some of the results of the W2R project are presented, namely the identification, quantification and characterization of the types of waste generated in renovation works to improve the energy efficiency of buildings and their possible applications as fillers in plasters to improve the performance of the original materials with a significant reduction in raw material, and thus reduce the environmental impact.Conclusions:Concrete and ceramics are the most commonly generated waste categories in building rehabilitation works to improve the energy efficiency of the buildings. These waste categories are generated during the preparation of the surface prior to the execution of the works. Also, mixed waste from insulation materials can be highlighted due to its volume.

Torrefaction of biomass from municipal solid waste fractions II: Grindability characteristics, higher heating value, pelletability and moisture adsorption

The microwave-assisted torrefaction of woody construction demolition waste (CDW) and grass clippings (GC) from municipal solid waste (MSW) was investigated under nitrogen-activated inert condition with respect to microwave power (250, 500 and 750 W), residence time (15, 30 and 45 min), moisture content (12, 16 and 20% w.b.) for CDW and 64% w.b. for GC. The results show that grinding energy consumption decreases as the microwave power level increases, indicating a significant improvement in the grindability of the material after torrefaction. Depending on the treatment combination, grinding energy savings of about 29–70% and 30–68% resulted after microwave-assisted torrefaction of CDW and GC, respectively. The higher heating value (HHV) increases with increasing microwave power level and torrefaction residence time. For CDW, the HHV increased by about 3–39% having HHV of 25,691 MJ/t. While for GC, the HHV increased by about 8–24%, having HHV of 20,936 MJ/t. This investigation further demonstrates that torrefaction reduced moisture adsorption of CDW and GC, which significantly improves their storage capability in humid locations. The moisture uptake ratios for torrefied CDW were found to be 0.66–0.96 and about 0.92 for torrefied GC, against a moisture uptake ratio of 1.0 for raw CDW and GC. However, biomass subjected to severe torrefaction process conditions produced pellets having poor physical quality. Microwave irradiation can be used effectively for torrefaction of MSW investigated at moderate microwave power level and short torrefaction residence time.

Torrefaction of biomass from municipal solid waste fractions I: Temperature profiles, moisture content, energy consumption, mass yield, and thermochemical properties

In this study, construction demolition waste (CDW) and grass clippings (GC) from municipal solid waste (MSW) were torrefied in a blown glass reactor using microwave irradiation with respect to microwave power levels (250, 500 and 750 W), torrefaction residence time (15, 30 and 45 min), moisture content (12, 16 and 20% w.b.) for CDW and 64% w.b. for GC, under nitrogen-activated inert condition. This investigation reflects that microwave power levels and torrefaction time have positive correlation on the temperature profiles. It shows that higher microwave power level contributed to higher heating rate and final temperature. Microwave power level and torrefaction time have negative correlation with the moisture content of CDW and GC after the torrefaction process. The higher the power level and torrefaction time, the higher the reaction temperature and the lower the moisture content of the torrefied MSW. Increasing the microwave power level and torrefaction residence time resulted to a corresponding increase in the thermochemical properties of the materials. As a result of torrefaction of CDW, elemental carbon increased by 1.3–39% over that of the non-torrefied CDW; while the elemental carbon of torrefied GC increased by 9–21% over that of the non-torrefied GC. The results show that the wetter the sample the less torrefaction energy is consumed and the more efficient the torrefaction process. At 500 W power level and 15 min torrefaction residence time of CDW, torrefaction energy of 4338 MJ/t and 3862 MJ/t were expended for 12 and 20% m.c., respectively.