• Journal of the Korean GEO-environmental Society
• /
• v.1 no.1
• /
• pp.19-26
• /
• 2000

This study is and experimental study to investigate the possibility of the utilization of paper ash as the cover and liner materials in the waste disposal landfill and other construction materials. A series of tests were performed to evaluate basic properties, compaction, compressive strength, consolidation, permeability, and CBR of paper ash. The sample used in these tests was obtained from four paper mills which are located in near Ch$\hat{o}$ngju. Bentonite and lime were used as addictives to improve permeability properties of paper ash. It was found that the maximum dry unit weight increases with the increase of the bentonite and lime contents. The results of unconfined compression tests show that paper ash meets the criteria of the unconfined compression strength. It is recognized that the permeability coefficient decreases as increasing bentonite content and the percentage of bentonite needed to make the permeability coefficient below $1{\times}10^{-7}cm/sec$ was 30%.

• Journal of the Korea Concrete Institute
• /
• v.26 no.4
• /
• pp.465-474
• /
• 2014

This is a comparative study that shows the overall environmental impacts from concrete structures when different compressive strength of concrete applied to structural systems having the same reference flow with different durability. A total of 24 MPa, 40 MPa and 60 MPa cases is analyzed to define the characteristic using end-point perspective LCA methodology including the stages of production, construction, maintenance and disposal. As results, global warming, non-renewable energy and respiratory inorganics problems are the major issues for assessing environmental impacts of concrete products.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.5 no.3
• /
• pp.305-312
• /
• 2017

This paper presents a laboratory investigation into the effects of fillers using industrial by-product such as coal ash, IGCC slag on properties of hot-mixed asphalt concrete variation with filler content. For comparison, existing mixture with lime and dust have also been considered. Marshall and flow test has been considered for the purpose of mix design as well as evaluation of mixture. Other performance tests such as indirect tensile strength test, tensile strength ratio(moisture susceptibility), dynamic stability have also been carried out variation with filler content. It is observed that the mixes with industrial by-product exhibit conform with quality standard. Therefore, it has been recommended to utilize industrial by-product based on fly ash wherever available, not only reducing the produce cost but also partly solve the industrial by-product utilization and disposal problem.

• Korean Journal of Construction Engineering and Management
• /
• v.14 no.1
• /
• pp.63-70
• /
• 2013

A judgment on the redevelopment projects' predicted profitability is an essential decision-making element for the success of the redevelopment projects. It is necessary to review the literature on profitability of redevelopment project and draw risk factors that could affect profitability through the risk analysis based on surveys. It is also necessary to judge profitability prediction toward the business value of the redevelopment project in the planning phase according to the risk analysis results which can affect the profitability prediction. In order to prevent the growing difficulties in executing the projects, a profitability prediction model is proposed using the method of management and disposal based on a proportional calculation that can estimate the share of expenses in order to judge profitability in the planning phase. With the improvement of profitability prediction models, it is possible to appropriately judge profitability in the planning phase in order to allow the prevention of suspension, reduction of project term, reduction of cost, and making of rational decisions.

• Journal of the Korea Institute of Building Construction
• /
• v.14 no.6
• /
• pp.523-529
• /
• 2014

Large amounts of waste shells have been produced each year from shellfish raising industries located in Korean costal areas. Due to the limited space for the waste shell disposal, the related environmental problem has been a serious issue. It is believed that using the waste shells as a source of aggregate for mortar, concrete or bricks can be a good solution. In this research, possibility of utilizing waste shells as an aggregate of mortar is investigated. Waste shells of manila clam, cockle, clam, sea mussel, and oyster were properly crushed, sieved, and sorted to meet the requirements of the grading of standard fine aggregate. After that, the waste shells were used as partial and total replacement of the fine aggregate, and their absorption and 28-day compressive strengths of mortar were measured. In general, replacement of waste shells increased the absorption and decreased the strength. However, one specimen with cockle increased compressive strength as replacement ratio increased. Mortar with cockle of 50% and 100% replacement showed higher compressive strength than that of control mortar. This increase of compressive strength was found to be affected by the strong interfacial bonding properties of the cockle and a cement matrix.

• Journal of Soil and Groundwater Environment
• /
• v.15 no.2
• /
• pp.47-54
• /
• 2010

Although the demands for the dredging work have been increasing due to social and industrial reasons including national plan for restoration of four major rivers, environmental standards or management guidelines for the dredged river sediment are limited. The suggested environmental standard for the beneficial use of dredged river sediment consists of two levels, recyclable and concern, and includes eight contaminants such as metals and organic contaminants. The systematic approach to remediate dredged river sediment is also suggested. The system consists of both washing and stabilization processes with continuous multi particle separation. In the early stage, the sediments are separated into two particle sizes. The coarse-grained sediment over 0.075 mm, generally decontaminated with less trouble, follows normal washing steps and is sent for recycling. The fine-grained sediments under 0.075 mm are separated again at 0.025 mm. The particles bigger than this second separation point are treated in two ways, advanced washing for highly contaminated sediments and stabilization for less. The lab test results show that birnessite and apatite are most effective stabilizing agents among tested for Cd and Pb. The most fine residues, down-sized by continuous particle separation, are finally sent for disposal. The system is tested for metals in this study, but is expected to be effective for organic contaminants included in the environmental standard, such as PAH and PCE. The feasibility test on the field site will be followed.

• Journal of the Korea Institute of Building Construction
• /
• v.18 no.5
• /
• pp.499-506
• /
• 2018

The number of demolition work is rapidly increasing because the middle- and high-rised buildings constructed over the rapid industrialization and urbanization have been deteriorated in social and structural aspects. However, theoretical approaches or studies related to the demolition cost prediction are still insufficient. Thus, this study derived and analyzed important factors affecting the fluctuation of the building demolition costs. 14 factors was derived through literature reviews and experts' interview, and the importance of each factor was analyzed to the each work(temporary work, structure demolition, and waste disposal) and the entire demolition work by using descriptive analysis. The survey results showed that the demolition costs was greatly influenced by environmental properties of the site. The results of this study can be used as a basis for estimating the approximate cost of the demolition work.

• Journal of the Korean Society of Safety
• /
• v.25 no.6
• /
• pp.115-122
• /
• 2010

The importance of the life cycle cost (LCC) analysis for bridges has been recognized over the last decade. However, it is difficult to predict LCC precisely since the costs occurring throughout the service life of the bridge depend on various parameters such as design, construction, maintenance, and environmental conditions. This paper presents a methodology for the optimal life cycle cost design of a bridge. Total LCC for the service life is calculated as the sum of initial cost, damage cost, maintenance cost, repair and rehabilitation cost, user cost, and disposal cost. The optimization method is applied to design of a bridge structure with minimal cost, in which the objective function is set to LCC and constraints are formulated on the basis of Korean Bridge Design Code. Initial cost is calculated based on standard costs of the Korea Construction Price Index and damage cost on damage probabilities to consider the uncertainty of load and resistance. Repair and rehabilitation cost is determined using load carrying capacity curves and user cost includes traffic operation costs and time delay costs. The optimal life cycle cost design of a bridge is performed and the effects of parameters are investigated.

• Journal of the Korea Institute of Building Construction
• /
• v.15 no.2
• /
• pp.153-160
• /
• 2015

The marble powder is a by-product that can be freely collected during the manufacturing process of marble, such as sawing, shaping, and polishing. Disposal of this waste powder is one of the environmental problems worldwide today. Therefore, this study investigated to solve this problem by consuming the waste marble powder in high fluidity concrete, as a pore filler. For this purpose, the waste marble powder was used as a binder replacing 5%, 10%, 15%, and 20% of cement in high fluidity concrete. After mixing, slump flow test, time-to-reach the slump flow of 500mm test, O-lot test and U-box test were conducted with fresh concrete. For the hardened concrete, compressive strength was determined at the age of 28 days. According to the test results, the workability of high fluidity concrete increased with the powder of 15% replacement, and the compressive strength of high fluidity concrete also increased with the same amount of powder.

• Journal of the Korea Institute of Building Construction
• /
• v.10 no.1
• /
• pp.147-153
• /
• 2010

The recycling of demolished concrete as an alternative source of coarse aggregates for the production of new concrete can help to solve the growing waste disposal crisis and the problem of the depletion of natural aggregates. The purpose of this study is to investigate the chloride migration of recycled aggregate concrete containing pozzolanic materials by the chloride migration coefficient. The specimens were made with recycled coarse aggregate at various replacement ratios (10, 30, 50%) and metakaolin, blast furnace slag, and fly ash is replaced for recycled concrete with a mixing ratio of 20%. The major results are as follows. 1) The compressive strength of recycled aggregate concrete containing pozzolanic materials increases as the curing age and chloride diffusivity decreases. 2) When the replacement ratio of recycled coarse aggregate is 30%, the chloride migration coefficient of recycled concrete containing blast furnace slag or metakaolin that shows a value similar to or lower than that of plain concrete at all ages.