• Magazine of the Korea Concrete Institute
• /
• v.21 no.2
• /
• pp.22-28
• /
• 2009

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.11 no.4
• /
• pp.509-516
• /
• 2023

The use of sulfur(S) in concrete has been variously studied as a way to improve salt resistance in concrete. However, sulfur is a solid material and is difficult to powder, which has disadvantages in its usability as an admixture or mixture for cement and concrete. For these problem, polymers such as dicyclopentadiene have been used to modify sulfur, but this also exists in a sticky state after modifying and does not improve the fundamental problem. So, reforming sulfur with slaked lime and the effect on cement hydration was examined by reforming sulfur with slaked lime, and the following conclusions were obtained. Depending on the reaction conditions, slaked lime modified bio-sulfur exists in a slurry state containing unreacted sulfur, unreacted slaked lime, calcium-sulfur(Ca-S) compounds and water. When slaked lime modified bio-sulfur is used as a cement mixture, salt resistance of concrete with slaked lime modified bio-sulfur is to be superior to that of plain concrete. This is believed to be because structure of cement hydrates with slaked lime modified bio-sulfur is to be more dense to that of plain cement hydrates by the continued presence of ettringite and can be used as a cement mixture in concrete.

• Environmental Engineering Research
• /
• v.24 no.4
• /
• pp.630-637
• /
• 2019

The present study aimed to investigate the potential of Enterococcus faecalis (E. faecalis) and Bacillus cereus (B. cereus) in improving the properties of bio-concrete. E. faecalis and B. cereus strains were obtained from fresh urine and an acid mire water at cell concentration of 1.16×10¹² and 1.3×10¹² cells mL^-1, respectively. The bacterial strains were inoculated in a liquid medium into the concrete with 1, 3 and 5% as replacement of water cement ratio (w/c). The ability of E. faecalis and B. cereus cells to accumulate the calcite and the decrement of pores size within bio-concrete was confirmed by SEM and EDX analysis. The results revealed that E. faecalis exhibited high efficiency for increasing of compressive and splitting tensile strength than B. cereus (23 vs. 14.2%, and 13 vs. 8.5%, respectively). These findings indicated that E. faecalis is more applicable in the bio-concrete due to its ability to enhance strength development and reduce water penetration.

• Journal of Environmental Impact Assessment
• /
• v.20 no.6
• /
• pp.815-821
• /
• 2011

This study aims to estimate the biological decomposition capacity of MPC(Microorganism Porous-Concrete). MPC has specific surface area formed by inside pores, and bio compound was added to those pores to reduce pollutants loading. To evaluate the water purification capacity of MPC, we carried out the comparative studies using different media types [GPC(General Porous-concrete), CPC(Compound porous-concrete), LPC(Lightweight aggregate porous-concrete)] under the condition of CFSTR, and different retention times (30, 60 and 120 min). We also estimated the purification capacity of MPC under different concentrations of pollutant loadings. The MPC showed higher efficiency in water purification function than other conventional porous concretes with efficient decrease rates of SS, BOD, COD, and nutrient concentrations. In the comparison experiment for different retention times, MPC showed the highest removal efficiency for all tested pollutants in the longest retention time(120 min). In the long period test, the removal efficiencies of MPC concrete were high until 100 days after the set up of the operation, but began to decrease. Outflow flux was invariable compared with inflow flux so that extra detention time for media fouling such as back washing is not needed. But the results suggested that appropriate management is necessary for long-term operation of MPC. As the final outcome, MPC using bio organisms is considered to be efficient for stream water purification when they used as substrates for artificial river structure.

• Korean Journal of Agricultural Science
• /
• v.38 no.3
• /
• pp.541-547
• /
• 2011

Korean building industry was developed by concrete and steel construction. However, concrete and steel have some problems which low carbon storage capability and difficulty of recycling. According to many studies, timber has high carbon storage capability, high recycling capability and sustainable supporting capability. Focus on this factors of timber, make new wall structure as Green Timber Wall panels and check the shear performance to use wall system in housing construction such as light-weight timber construction and nondearing wall on other construction. In the results, B-4-B and B-4-S show similar modulus of shear stiffness on the table. GH-4-GH has slip shape failure mode between Green Timber Wall boards. GH-4-GV has most stable characteristic curve than other specimens.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.7 no.4
• /
• pp.316-322
• /
• 2019

A probabilistic approach considering uncertainties was employed to investigate the effects on the material characteristics and strength of nuclear bio-logical shield concrete walls, when exposed to long-term radiation during the entire service life. Time-dependent compressive and tensile strengths were estimated by conducting the neutron fluence analysis. For the contaminated concrete, individual compressive and tensile failure probabilities can be possibly evaluated by not only establishing limit-state function withthe predefined critical values but also performing Monte Carlo Simulation. Nuclear power plant types similar to the Kori Unit 1, which was shut off permanently in 2017 after the 40-year operation, were herein selected for an illustrative purpose. Consequently, the probability-based performance assessment and prediction of contaminated concrete walls were well demonstrated.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.15 no.4
• /
• pp.119-132
• /
• 2012

The unmanaged abandoned concrete roads are vulnerable toward the issues on soil and water pollution, which requires flexible managing method such as eco-corridor after the process of ecological restoration. Among various alternations of abandoned concrete-paved roads, ecological restoration technique may be the most suitable method in sites including high quality of natural environment. Therefore, as in Young dong province, GyungBu express highway (227.24~229.04km), which is near to Hwang-gan IC, the survey to measure its effect of soil under the paving and water pollution by abandoned concrete roads was discussed. Then, the restoration method of plantings of landscape trees and hydro-seeding methods of artificial soil media was appraised through consecutive monitoring. The soil adequacy analysis shows lower percentage of heavy metal substance in each depth level compared to standard limit stated by the Ministry of Environment, along with low concerns raised after the analysis on heavy metal content of the spilled water on the concrete roads. Meanwhile, Korean Weigela (Weigela subsessilis L.H. Baily) was found to be withered in small-scale landscape trees planting sites. Among the seeding plants. the family of leguminosae, Silene armeria, Dendranthema boreale, Caryopteris incana and Aster yomena show good establishment results. Overall studies on planting of small and large landscape trees, planting method of container plants, planting method of ground cover plants, and germination and development trend of seeding plants of the experimental restoration site on abandoned concrete roads are revealing specific trends in the way landscape woody plants establishment and growth. Finally, this study suggests further studies and survey on varied plant restoration methods on abandoned concrete-roads for developed design guidelines of their methods.

• Journal of the Korea Concrete Institute
• /
• v.28 no.6
• /
• pp.703-711
• /
• 2016

The present study is mainly aimed at securing adequate pores which are applicable to the aquatic environment and satisfying the required strength of porous concrete as a structure by substituting pumice for crushed stone which is usually used for the fabrication of porous concrete. Accordingly, in order to deduce the optimum mixing conditions applicable to the aquatic environment, we sought to evaluate the porosity, coefficient of permeability and compressive strength of porous concrete based on the target porosity and the mixing factors for pumice. By examining the porosity and coefficient of permeability of porous concrete and the physical properties of its compressive strength based on the target porosity and the mixing factors for pumice, it is judged that the optimum mixtures for porous concrete applicable to the aquatic environment which satisfy both the necessity of securing adequate pores and the required strength for porous concrete as a structure are PC I I-10-0, PC I I-10-5 and PC I I-10-10.

• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 1997.11a
• /
• pp.20-26
• /
• 1997

The design or analysis of beehouse inside temperature environment based on steady heat transfer theory causes much deviation and theoretically it is impossible to control the inside temperature lower than the outside temperature under the condition that the bee produces heat and no cooling equipment is installed. But in practical use of beehouse, the inside temperature is somehow lower than the outside temperature because of the heat inertia of concrete floor. (omitted)

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.10
• /
• pp.668-676
• /
• 2018

Most reservoirs in Korea have a low water depth and are small in size. Water pollution of the reservoir is serious because of the organic matter flowing from livestock wastewater, domestic sewage, and farmland. In this study, an attempt was made to improve the water purification effect by replacing the secondary dam installed in the depression area of the agricultural reservoir with the riprap dam. To evaluate the long-term performance, a riprap dam was installed in a reservoir in Gyeonggi province and water purification effect for 36 months was measured. The field test results showed that COD was 14.6%, SS 38.6%, T-N 9.5%, and T-P 11.2%. The concentrations in the influent water exhibited a significant change according to season, and the water purification effect increased with increasing concentration of influent water. The pollutant flowing into the lake from the depression area can be blocked effectively if the secondary riprap dam for water purification is installed in the agricultural reservoir.