• Journal of the Korean Geotechnical Society
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• v.19 no.1
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• pp.163-172
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• 2003

The engineering properties of composite silicate grout materials that were developed recently were analyzed. In this laboratory tests, OPC (Ordinary Portland Cement) was mainly used as grout materials. Moreover, the properties of composite silica, silica sol and sodium silicate (No.3) acting as coagulating agent were analyzed and compared with each other. For the purpose of finding the engineering properties of composite silicate grout materials, various physical and chemical tests were performed : naked eye measurement, photographing by using SEM, uniaxial compression test and in-situ application test. A series of test results showed that the strength of composite silicate grout materials was about 3～6 times that of ordinary sodium silicate grout materials in 6～24hr. Especially, based on the evaluation of the application of JS-CGM grout to the construction fields, composite silicate grout would be very effective in reducing the coefficient of permeability.

• Journal of the Korean GEO-environmental Society
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• v.21 no.12
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• pp.35-41
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• 2020

Recently, underground spaces have been developed variously due to the concentration of the building structure in downtown area and reconstruction of the apartment. However, various problems such as differential settlement are occurring in the waterproof and reinforcement construction. In grouting method, which is frequently used for the ground reinforcement, quality control was performed by measuring the injection quantity of grouting materials and performing laboratory tests using boring samples, but it is difficult to determine whether the ground reinforcement has been performed properly during the construction stage. In order to solve this problem, a research is needed to carry out quality control by measuring electric resistivity after grouting is performed using grouting materials mixed with conductive materials. In this research, as a basic study of the new grouting method using conductive materials, uniaxial compression tests were performed using cement specimen with 0, 3, 5, 7% of carbon fiber to evaluate the effect of conductive material on the performance of grouting material. Based on the test results, the uniaxial compressive strength is increased with the mixed proportion of the carbon fiber increase. Furthermore, the carbon fiber can also affect on the early-strength of the grouting materials.

• Journal of the Korean Geotechnical Society
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• v.26 no.7
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• pp.107-115
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• 2010

In this paper, the applicability of cement grout bas been studied as an alternative to bentontite grout to backfill ground heat exchangers. To provide an optimal mixture design, the groutabilty and thermal conductivity of cement grouts with various mixture ratios were experimentally evaluated and compared. The unconfined compression strength of cement grout specimen was measured, which was exposed to cyclic temperature variation ranging from $50^{\circ}C$ to $-5^{\circ}C$. In addition, the integrity of the interface between circulating HDPE pipes and cement grout was evaluated by performing equivalent hydraulic conductivity tests, on the specimen. in which a pipe locates at the center of the specimen.

• Journal of the Korea Institute of Building Construction
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• v.24 no.2
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• pp.215-226
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• 2024

This study presents an experimental investigation into the performance of self-sensing grout formulated with a high volume of ultra-fine fly ash(UHFA). To explore the potential benefits of alternative cementitious materials, the research examined the effect of substituting UHFA with equal parts of blast furnace slag(BFS) fine powder. Both UHFA and BFS are byproducts generated in significant quantities by industrial processes. The evaluation focused on the fresh properties of the grout, including its flow characteristics, as well as the hardened properties such as compressive strength, dimensional stability(length change rate), and electrical properties. The experimental results demonstrated that incorporating UHFA resulted in a substantial reduction in the plastic viscosity of the grout, translating to improved flowability. Additionally, the compressive strength of the UHFA-modified grout surpassed that of the reference grout(without UHFA substitution) at all curing ages investigated. Interestingly, the electrical characteristics, as indicated by the relationships between FCR-stress and FCR-strain, exhibited similar trends for both grout mixtures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.3
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• pp.19-26
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• 2024

In this study, the compressive behavior of a 1/12.5 scale model of a wind tower support structure connection was experimentally analyzed. A high-performance cementitious grout with a compressive strength of 140 MPa was used to fill the connection, and experiments were conducted with shear key spacing, the shape, and connection length as variables. When the number of shear keys in the connection is the same, the smaller the spacing of the shear keys than the length of the connection, the higher the shear strength, and for the same spacing and connection length, the higher the height of the shear keys, the higher the strength. In addition, it was found that the strength showed a linear behaviour until the connection slip reached 1.0 mm, and it reached the maximum strength at 7.0 mm connection slip showing a non-linear behaviour as the load increased. It was found that the failure mode changed from interfacial shear failure to grout failure as the strength increased according to the shape and spacing of the shear key, and brittle failure did not occur due to steel fibers.

• The Journal of Engineering Geology
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• v.12 no.1
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• pp.63-73
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• 2002

To evaluate reinforced region of dike by cement grouting, we investigated both the electrical resistivity and the strength of cement grout having various water-cement ratio with curing time. These investigation results showed that the electric conductivity of grout is much higher than that of water and that the apparent resistivity of grouted region is much lower than that of unoccupied region by grout. It was founded that electrical resistivity survey might be quite effective to detect grout region in dike. As the results of electrical resistivity sounding at three dikes, apparent resistivities after grouting showed several tens to several hundreds of ohm-m which were lower than those of pre-grouting and showed stabilizing trend with curing time. From these results, we could estimate that this behavior of apparent resistivity is due to increasing strength with curing time.

• Journal of the Korean GEO-environmental Society
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• v.22 no.12
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• pp.59-63
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• 2021

This study presented the characteristics and additive effects of the grout with mixing ratio for developing of high-efficiency grouting technology under high depth conditions. The laboratory investigation were conducted with Portland cement (OPC) and micro cement (S8000-E) including viscosity experiments, particle size analysis experiments, Gel-Time experiments and uniaxial compressive strength experiments. As a result of the viscosity experiment, it was shown that OPC is advantageous in terms of viscosity, but S8000-E is suitable when considering the passage of rock joint intervals through particle size analysis. The Gel-Time experiment shows that it is not that difficult with injection as a grout material even when silica fume (SF) was applied. The strength of the cured material is improved as increase in the content of silica fium (SF). Within the range of the study, the optimal mixing ratio obtained through various experiments is S8000-E, w/c=70%, silica fium (SF)=6%, and 7 days.

• The Journal of Engineering Geology
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• v.31 no.1
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• pp.67-81
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• 2021

Grouting is used for reinforcement and waterproofing of soft ground to increase its bearing capacity, reduce the impacts of rising or lowering groundwater levels, and reduce subsidence due to vibration and general causes. This study investigated the enhancement of grout strength and hardening time by the addition of reinforcing fibers, and the development of non-cement grouting materials from blast furnace slag. An experiment was performed to measure the increase in grout strength resulting from the addition of 0.5% increments of aramid and carbon reinforcing fibers. The results show that the uniaxial compressive strength of grout increases with increasing content of reinforcing fiber. Comparison of three admixtures of finely powdered blast furnace slag and 10%, 20%, and 30% calcium hydroxide stimulating agent showed that the uniaxial compressive strength of the mixture increases with increasing content of alkaline stimulant; however, the strength was lower than for 100% pure cement. The reaction of calcium hydroxide with blast furnace slag powder, which increases the strength of the grout, is more effective if injected as a solution rather than a powder.

• Resources Recycling
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• v.27 no.6
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• pp.30-37
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• 2018

A series of experiment was conducted to evaluate basic performances of low-pH, anti-washing grouts incorporating gypsum which applied for reinforcing underwater cavities in limestone- grounds. Various types of mix proportions were designed and the fluidity, strength and environmental impact of these mixtures were evaluated. The flowability was evaluated under two conditions, i.e., flows without and with pressing, respectively. Strength was measured for the hardened mixtures fabricated under conditions of air and water injections. The environmental impacts including the pH of the suspension and the suspended solids concentration for the mixtures were evaluated. The low pH of fresh mixture suspension, below than 10, was achieved by incorporation of gypsum. The mix proportions of cement-quartz powder-gypsum binders and chemical agents resulted in mortar natural flow 7-10 cm and uniaxial compressive strength 4 MPa were derived.

• Journal of the Korea Concrete Institute
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• v.28 no.5
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• pp.519-525
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• 2016

This paper reports on analyzing the free and restrained shrinkage characteristic of ternary grout used cementitious admixture. In this study, the cementitious admixture was used such as fly ash, ziricania silica fume by combination of expansive additive (a, b) and shrinkage reducing agent. And a number of basic performance tests were conducted to investigate bleeding, volume change, fluidity and compressive strength behavior. According to the results, within appropriate mixing ratio, even the fluidity is not influenced by expansive additive and shrinkage reducing agent, the resistant properties of bleeding, volume change, shrinkage and compressive strength are increased. Comparing with plain grout, the free shrinkage reduced by a minimum of 29% which specimens are added expansive additive and shrinkage reducing agent. The combination of expansive additive a and shrinkage reducing agent is the most effective for reduction of shrinkage. And increasing the mixing ratio of expansive additive and shrinkage reducing agent extended cracking time. Nevertheless, combined addition of expansive additive a 2.0% and shrinkage reducing agent 0.50% has best shrinkage reduction behavior and not appeared cracking. From the above, the mixing ratio of 2.0% of expansive additive a and 0.50% of shrinkage reducing agent is high performance ternary grout for PSC bridge.