• Journal of Soil and Groundwater Environment
• /
• v.20 no.7
• /
• pp.90-102
• /
• 2015

To understand the hyrogeochemical variation of bedrock aquifer during underground space construction, various graphical methods including multiple-component plots and chemical trends were used to estimate the mixing rate between seawater and freshwater and to investigate the evolution of water quality. The water chemistry and mixing rate between fresh and sea waters, which are generally localized in the construction area (MW-7, in land), shows typical characteristics of freshwater that doesn’t affect its validity as seawater intrusion. Especially, the water chemistry of a MW-4 (coastline) was classified as Na-Cl type, Na-HCO₃ type, and Ca-Cl type due to the influence of the seawater intrusion. And hydrogeochemical and isotopic data show that local freshwater is subjected to geochemical processes, such as reverse ion-exchange. Throughout the Chadha’s diagrams, four different case histories with the temporal and spatial variation of groundwaters in the study area were proposed, which is recommended to interpret the hydrogeochemical reactions effectively.

• Geomechanics and Engineering
• /
• v.19 no.4
• /
• pp.307-314
• /
• 2019

Light construction waste (LCW) particles are pieces of light concrete or insulation wall with light quality and certain strength, containing rich isolated and disconnected pores. Mixing LCW particles with soil can be one of the alternative lightweight soils. It can lighten and stabilize the deep-thick soft soil in-situ. In this study, the unconfined compressive strength (UCS) and its mechanism of Construction Waste Stabilized Lightweight Soil (CWSLS) are investigated. According to the prescription design, totally 35 sets of specimens are tested for the index of dry density (DD) and unconfined compressive strength (UCS). The results show that the DD of CWSLS is mainly affected by LCW content, and it decreases obviously with the increase of LCW content, while increases slightly with the increase of cement content. The UCS of CWSLS first increases and then decreases with the increase of LCW content, existing a peak value. The UCS increases linearly with the increase of cement content, while the strength growth rate is dramatically affected by the different LCW contents. The UCS of CWSLS mainly comes from the skeleton impaction of LCW particles and the gelation of soil-cement composite slurry. According to the distribution of LCW particles and soil-cement composite slurry, CWSLS specimens are divided into three structures: "suspend-dense" structure, "framework-dense" structure and "framework-pore" structure.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.8 no.1
• /
• pp.41-48
• /
• 2013

Waste Stone and Waste Stone Powder are recycling some cyclic aggregate only. And the greater part of Waste Stone and Waste Stone Powder are reclaining or neglecting. To solve this problem, the government is proceeding development of cementitious scagliola using waste stone and waste stone powder. However, quality standard for cementitious scagliola using waste stone and waste stone powder has not been established. So cementitious scagliola using waste stone and waste stone powder has problem of quality assurance. Therefore in this study, developed standard for Evaluating Performance of cementitious scagliola using waste stone and waste stone powder through survey of international standard.

• Magazine of RCR
• /
• v.4 no.3
• /
• pp.7-14
• /
• 2009

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2007.04a
• /
• pp.75-78
• /
• 2007

The recycling program about waste concrete is being progressed to national research. But research on waste concrete powder which is occurred in control process of concrete powder is not enough. Waste concrete powder includes in $SiO_2,\;Al_2O_3$, and CaO so that the create of tobermorite is possibile through Hydrothermal Syntesis Reaction. Tobermorite have an advantage of high strength, sulphuric acid resistance and the lower drying shrinkage. Accordingly, this study investigate in properties of light-weight foamed concrete made with waste concrete powder. As a results, light-weight foamed concrete made with waste concrete powder is the higher than stone powder sludge of density and porosity, and the tower compressive strength. Therefore, it is thought that light-weight foamed concrete using waste concrete powder is possible.

• Geomechanics and Engineering
• /
• v.28 no.6
• /
• pp.559-571
• /
• 2022

Deep soil mixing, DSM technique has been widely used to improve the engineering properties of problematic soils. Due to growing urbanization and the industrial developments, disposal of brick dust poses a big problem and causes environmental problems. This study aims to use brick dust in DSM application in order to minimize the waste in brick industry and to evaluate its effect on the improvement of the geotechnical properties. Three different percentages of cement content: (10, 15 and 20%) were used in the formation of soil-cement mixture. Unlike the other studies in the literature, various percentages of waste brick dust: (10, 20 and 30%) were used as partial replacement of cement in soil-cement mixture. The results indicated that addition of waste brick dust into soil-cement mixture had positive effect on the inherent strength and stiffness of loose sand. Cement replaced by 20% of brick dust gave the best results and reduced the final setting time of cement and resulted in an increase in unconfined compressive strength, modulus of elasticity and resilient modulus of sand mixed with cement and brick dust. The findings were also supported by the microscopic images of the specimens with different percentages of waste brick dust and it was observed that waste brick dust caused an increase in the interlocking between the particles and resulted in an increase in soil strength. Using waste brick dust as a replacement material seems to be promising for improving the geotechnical properties of loose sand.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2015.11a
• /
• pp.49-50
• /
• 2015

Recently, by-products from concrete industry are generated in large quantities because of urban redevelopment. Accordingly, waste concrete powder(WCP) inevitably generated in the course of crushing, screening, and separating the waste concrete also show high emission and be increasing gradually, but which is mostly buried with waste concrete aggregate. This is a basic research to increase the value added utilization rate of WCP. We have examined strength characteristic of extruding panel with WCP, depending on the curing methods. The result of study shows similar strength to the base specimen in autoclave curing condition. And in autoclave curing condition, the specimen with WCP of 20% and 30% satisfy the target strength of 14MPa.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2014.05a
• /
• pp.252-253
• /
• 2014

This study is to XRD and image analysis of low carbon type recycled cement from waste concrete powder and cement raw materials. Waste concrete powder possible to low carbon type recycled cement in small part of additive materials. Also, low carbon type recycled cement using waste concrete powder is suitable for ordinary portland cement.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2003.05a
• /
• pp.81-87
• /
• 2003

The purpose of this study is the development of a recycling process to recover the hydrated ability of cement hydrate which accounts for a large proportion of cementitious powder by concrete waste in order to recycle cementitious powder by concrete waste as recycle cement. Therefore, after having theoretical consideration based on the properties of high-heated concrete, we consider the properties of hydration of cementitious powder in hardened mortar under various temperature conditions. As a result of experiment, it is revealed that an effective development of recycling cement is possible since the cementitious powder by concrete waste recovers a hydraulic property during burning at $600^{\circ}C$ or $700^{\circ}C$. And it is shown that the fluidity of mortar decreases rapidly as the burning temperature of recycle cement increases. however, the improved effect of fluidity is predominant if adding the additive such as fly-ash or blast furnace slag.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2016.05a
• /
• pp.191-192
• /
• 2016

Recently, there have been many studies about recycling cementitious powder from concrete waste, generated after recycle aggregate production. Previous studies showed that when the heating process of waste powder in paste is dehydrated making possible the restoration of hydraulic properties. Thus the purpose of this study is to make an experimental review on properties of concrete products made vibration-compressive according to waste concrete powder.