• International conference on construction engineering and project management
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• 2015.10a
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• pp.405-410
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• 2015

Today, the booming construction in Ethiopia is leading to an increased demolition of concrete structures whereby these demolished structures are disposed at landfills. The current practice is creating a huge amount of waste which is environmentally unfriendly and is becoming the main source of pollution in communities. This paper discusses the potential use of demolished concrete from site tested specimens as a recycled aggregate material for new structural concrete. The mechanical, physical and chemical properties of RCA are studied to understand the suitability in the production of recycled concrete. Tests including gradation, unit weight, soundness, density, and abrasion will be conducted to assess RCA properties. Since the percentage of RCA govern the strength of concrete, a C25 concrete is mixed by the ratio of 25%, 50% & 100% RCA with and without water reducing admixture and a control mixture composed of natural aggregate. The output of this study will highly impact the growing construction industry and communities in Ethiopia thereby reducing waste, saving cost, conserving natural aggregates, building capacity and setting quality standards.

• Korean Journal of Construction Engineering and Management
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• v.11 no.2
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• pp.45-53
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• 2010

When increasing quantity of construction wastes, how to deal with construction wastes and environmental problems relating to disposal of construction wastes are discussed as social issues, treatment of construction waste and subsidiary issues are raised as important problems. The demolition work produce construction wastes most in construction industry. Various researches on eco-friendly treatment of construction wastes, recycling rates and recycled materials were conducted aspect of sustainability in developed countries, however, domestic remodeling projects were performed demolition work with first-demolition and second-classification method which emphasize productivity focused on efficiency. It caused not only environmental problems, but also economical problems such as increasing disposal cost of construction wastes. Solving these problems, the previous study, suggested the process model of eco-friendly demolition work to recycle materials. This paper applied eco-friendly remodeling process to practical projects and economic feasibility on eco-friendly remodeling process. Moreover these results expect to contribute the revitalization of eco-friendly demolition work in remodeling projects.

• Korean Journal of Construction Engineering and Management
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• v.15 no.6
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• pp.63-70
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• 2014

Deconstruction of the building must be applied firstly in order to improve recycling and reuse of construction wastes. In this study have done a case study for deconstruction of an apartment. All construction waste(CW) which will be generated during deconstruction was examined in each part of the building. Because drawing did not exist in most of the old building, we drew up floor plans of buildings. After analyzing these drawings, estimated quantities of CW. It was measured working time of labor and equipments for deconstruction and general demolition on each building of the apartment. In addition, it was proposed in the volume and weight per unit after analyzing detailed measurement of CW which was generated in the process of deconstruction and traditional demolition. It suggested recovery rate at a site, volume and weight conversion factors, and waste basic unit per area that based on the results of comparative analysis on the amount of CW which is calculated from drawing and generated at a site. These factors will be used fundamental materials for estimating quantities and treatment cost of CW, and scheduling of works.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.634-637
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• 2004

Hereafter, the housing construction industry in a domestic country has to give more relative importance to the redevelopment and the rebuilding of existing housing rather then the housing supply methods by the development of new housing sites, and those tendencies are rapidly spreading out. Also, because apartment occupies $50\%$ over of the existing housing, its maintenance, repair, remodeling and reconstruction got to be necessary area for the slumming prevention of a residential area and the disaster prevention occurred by durability lowering of building. But, as having focused on the housing supply methods by the development of new housing sites, the domestic construction industry has relatively carelessly dealt with deconstruction areas including maintenance, remodeling, redevelopment and reconstruction of old existing housing. Therefore the process of the deconstruction is not well suited to regulations and related technology. This paper suggests the present situation of C&D production and new demolition process through comparative analysis of the present demolition works.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.481-484
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• 2008

Recently, the recycling and reusing of construction and demolition waste concrete is urgently required because waste concrete is greatly increased according to the rapid increasing of urban redevelopment project, but the problem solution for demand and supply unbalance of fine aggregate is urgently required because of the restriction of collecting sea fine aggregate. So the utilization of high quality recycled fine aggregate using construction and demolition waste concrete as new fine aggregate for construction industry is urgently. Accordingly, In this study, As recycled fine aggregate manufacturing technology with exceeding in economical efficiency, reduction efficiency of environmental load and quality improvement effect of recycled fine aggregate, it is to develop dry manufacturing system composed specific gravity separator of high-speed rotation impact type and centrifugal Force Powder Collector, etc. And it is to examine mechanism of recycled sand dry manufacturing system.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.102-105
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• 2001

Gypsum has been known as a prominent material for improving alkali soil, and this material can be supplied easily in large scale by recycling waste gypsum plasterboard from construction and demolition sites in advanced countries. In April 2000, in the part of western Jilin Province in China, where alkali soil spread vastly, we conducted a cultivating experiment of corn and rice after treating with granule recycled waste gypsum at six alkali soil fields which total area were 14000$m^2$. We confirmed that pH of soil decreased in a short period and alkali soil changed soft a desirable condition for farm work, and furthermore, gypsum caused to accelerate the growth of a plant, both corn and rice.

• Advances in concrete construction
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• v.5 no.3
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• pp.201-219
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• 2017

With the rapid growth in construction sector, it becomes all the more important to assess the amount of Construction and Demolition (C&D) waste being generated and analyze the practices needed to handle and use this waste before final disposal. This serves waste management and disposal issues, paving way to waste utilization in construction industry from the sustainability point of view. C&D waste constitutes a major bulk of total solid waste produced in the world. In this work, an attempt is made to study the performance of concrete using water soaked Recycled Coarse Aggregates (RCA) in replacement levels of 0%, 25%, 50%, 75% and 100% to Natural Coarse Aggregates (NCA). Experiments were designed and conducted to study the performance of RCA based concrete. Further suitable performance enhancement techniques to RCA based concrete were attempted, to achieve compressive strength at least equal to or more than that for no RCA based concrete (control concrete). Performance enhancement study is reported here for 50% and 100% RCA based concretes. All four techniques attempted have given favorable results encouraging use of RCA based concretes with full replacement levels, to adopt RCA based concrete in structural applications, without any kind of concern to the stake holder. Further attempts have also been made to use Recycled Fine Aggregates (RFA) with appropriate modifications to serve as fine aggregates in mortar and concrete. Using RFA blended with river sand fractions as well as RFA with Iron Ore Tailings (IOT) fractions, have given good results to serve as fine aggregates to the extent of 100% replacement levels in mortars and concretes.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.544-549
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• 2009

Alongside the increasingly larger domestic construction projects is the gradual rise in construction waste. Consequently, serious environmental problems emerge. The increase in demand for housing remodeling due mainly to the increase in national income and improvement of quality of life is the main reason for the increase in construction waste. This study was conducted as the basic study for the prevention and reduction of construction waste generated by apartment remodeling; it aimed at identifying the remodeling items and reasons. Toward this end, this study targeted apartments at least 15 years old and conducted a questionnaire survey to determine the remodeled sections and remodeling reasons. As a result of the questionnaire survey, the bathroom, floor finishing, and kitchen furniture recorded the highest ratios in remodeling. Old materials, aesthetic motivation, and pleasant living space composition were cited as the major remodeling reasons. This study is significant as a basic study for generating environmental and economic profits through systematic waste management. Further studies should develop guidelines suitable for construction waste reduction and recycling in line with the construction and demolition phases in case of remodeling.

• Journal of Korea Society of Waste Management
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• v.35 no.8
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• pp.785-798
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• 2018

Since the Framework Act on Resource Circulation was enacted in 2018, the government should establish a National Resource Circulation Master Plan every 10 years, which defines mid- to long-term policy goals and directions on the efficient use of resources, prevention of waste generation and recycling of waste. In addition, we must set mid- to long-term and stepwise targets for the final disposal rate, recycling rate (based on sorted recyclable materials and recycled products), and energy recovery rate of wastes, and relevant measures should be taken to achieve these targets. However, the current industrial waste (IW) statistics have limitations in setting these targets because the final disposal rate and recycling rate are calculated as the ratio of the recycling facility input to the IW generation. In this study, the material flow from the collection stage to the final disposal of industrial waste was analyzed based on the generation of 2016, and the actual recycling amount, actual incineration amount, final disposal amount and their rates were calculated. The effect on the recycling, incineration and final disposal rates was examined by changing the treatment method of nonhazardous wastes from the factory and construction and demolition wastes, which were put in landfills in 2016. In addition, the variation of the waste treatment charge was investigated according to the change of treatment methods. The results of this study are expected to be effectively used to establish the National Resource Circulation Master Plan and industrial waste management policy in the future in South Korea.

• Resources Recycling
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• v.17 no.2
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• pp.16-29
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• 2008

According to the statistical data of the Ministry of Environment, 47million tons of construction waste were generated, and 96.7% of them was recycled in 2005. However, the recycled products seem to be remained under low quality. Because mixed demolition and construction waste, so called DC Waste, including concrete, brick, plaster, lumber, plastics building materials, paper and some dirt and stone, is very variable and difficult to estimate its exact composition, it is regarded as having little or no value to the construction industry. 'The Research group on recycling of construction waste' was started by the Housing & Urban Research Institute(KNHC), which is sponsored as a large scale national project by the Ministry of Construction and Transportation. This research group intends to establish recycling system through planing, processing, developing practical technology, and eventually contribute to save natural resource and to vitalize the industry. In this paper an overview of DC waste management and recycling technology is given in some detail. Particularly, "recycling law of construction waste" and recent research trends on recycling of construction waste are discussed.