• Explosives and Blasting
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• v.38 no.4
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• pp.46-52
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• 2020

Although anti-washout grouts are used extensively in underwater targets, major constraints continue to be associated with their use. These include poor bonding strength, poor pumpability, and loss of high strength in everyday engineering applications. In this study, based on the literature pertaining to self-compacted, non-dispersive, anti-washout grouts, a review of research trends in anti-washout grouts for underwater construction and sealing of karst cavities was carried out in order to determine the problems faced in this field. Grouts used under water suffer a loss of strength and bonding strength in comparison to grouts cast in air. Researchers are designing high-viscosity grouts to overcome the inrush of water and seal karst cavities; however, in doing so, they have inadvertently caused serious problems pertaining to the pumpability of these grouts and concretes in deep target locations. Thus, the majority of the anti-washout grouts and concretes that have been developed are not applicable to deep target environments, instead being suitable for only near-surface targets.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.141-146
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• 1999

An experimental study is carried out to estimate the effects of mixing and placing condition on the mechanical properties of anti-washout concrete. According to the test results, mixing method and placing temperature do affect the characteristics of rrsh concrete, while they do not affect the strength development of anti-washout concrete. But, concrete strength was greatly affected by the placing condition and placing height. Concrete strength decreases linearly as the placing height increased. Compared to the normal concrete, the increase in strength is not associated much with an increase in the elastic modulus of anti-washout concrete.

• Applied Chemistry for Engineering
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• v.23 no.5
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• pp.480-484
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• 2012

Concrete, the mixture of cement, sand, gravel and water, is a suspension substance extensively used to construct building materials. When a concrete mortar is applied to the underwater construction, the rheology of concrete is of great importance to its flow performance, placement, anti-washout and consolidation. In this research, the anti-washout and rheological properties of concrete have been investigated with concrete admixtures prepared by adding anionic surfactants, cationic surfactants, and polymeric thickeners. The concrete mortar formulated by pseudo-polymeric systems with the electrostatic association of anionic and cationic surfactants, showed high viscosities and suitable anti-washout properties, but poor pumpabilities. The addition of poly methyl vinyl ether to the mixed surfactant system exhibits synergistic effects by improving the concrete mortar properties of the concrete mortar such as fluidity, visco-elastic property, self-leveling, and anti-washout.

• Journal of the Korean Geosynthetics Society
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• v.12 no.2
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• pp.25-33
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• 2013

This study introduces strength characteristics of the anti-washout grouting material using viscous modifiers and its characteristics mixed with coarse materials. Especially, this study focused on the strength characteristics of the grouts mixed with sea water. It is found that the anti-washout grout mixed with sea water has enough strength and good resistance to segregation just like that with fresh water. Also, a small scale test was performed to evaluate the solidification characteristic of the anti-washout grout mixed with coarse fill materials. It is also found that the strength of anti-washout grout mixed with coarse fill materials is greater and better segregation resistance than those of conventional grout with fill materials.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.267-270
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• 1998

Recently, underwater concrete constructions are increasing. Therefore it is considered important to control the quality of underwater concrete. In this paper, we have an intention of evaluating fundamental properties of underwater concrete using the anti-washout admixtures. Thus, it has been investigated that the setting slump flow of the concrete, pH value and suspended solids in solution, compressive strength on both of specimens made above and under water. Also the percentage of fine aggregate has been found to alter the compressive strength in underwater concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.366-372
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• 1996

This paper persents the characteristics and properties of the five domestic and foreign-made anti-washout admixtures commercially available in Korea. These admixtures have been analysed by experiments to compare among others specifically on the following items : air content, slump-flow, hardening time, pH, filling condition, turbidity, content of chloride, compressive strength of underwater concrete and ratio of ambient / underwater concrete compressive strength. The mix design for comparison has been set according to the Japanese practicesince there is still no guideline concerning underwater concrete available domestically.

• Journal of Ocean Engineering and Technology
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• v.19 no.6 s.67
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• pp.29-34
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• 2005

This paper describes the effect of fly ash replacement on seawater resistance of anti-washout underwater concrete, which was replaced cement by fly ash from $0\%$ to $50\%$. The experimental work was performed to find out the variations of length and weight of specimens, using a chloride acceleration test in $40\^{\circ}$C The results shaw that the admixture using fly ash on an anti-washcout underwater concrete in the sea environment makes it more durable for the attacks of chloride by seawater. Also, the length of specimens of anti-washout underwater concrete, at age 180 days, increased substantially, compared with normal concrete; however, the mixture in which cement was replaced $50\%$ of fly ash shows $93\%$ reduction of the expansion, compared with the normal anti "washout underwater concrete specimen.

• Tunnel and Underground Space
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• v.26 no.5
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• pp.418-430
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• 2016

In this study, experimental study on cement grout materials containing anti-washout admixtures or accelerators in grout column for reinforcement technology in groundwater-saturated mining cavity was conducted. As a result, the cement milk containing anti-washout admixtures was suitable for mixed aggregates, and the cement mortar containing anti-washout admixtures and the cement milk containing accelerators were suitable for crushed stone aggregate in terms of forming grout column. Especially, in the case of crushed stone aggregate injecting the cement milk containing accelerators, the diameter of the grout column was greatest and the void of the crushed stone aggregate was filled with grout materials. Therefore the case of crushed stone aggregate injecting the cement milk containing accelerators is considered for optimal grout materials and aggregate.

• Journal of the Korean GEO-environmental Society
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• v.15 no.9
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• pp.59-67
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• 2014

With increasing underwater structure construction, there is high interest in offshore foundation and underwater grout and various study has been done in this area. For grout materials constructed underwater, it may be washed away by water or easily disturbed and material separation phenomenon during curing period always happens. As a result, it is difficult to ensure construction quality and this has a significant influence on the design strength of structure. In this study, to understand application effects of anti-washout admixture for the preplaced construction method, where grout is injected in monopile after filled with aggregates, laboratory tests on bleeding and compressive strength of anti-washout admixture were performed under various test conditions varying size of aggregate, water and cement ratio and admixture, and test results were compared and evaluated.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.152-155
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• 2009

Purpose: The most widely accepted tool for follow up management of thyroid cancer patients is serum thyroglobulin (Tg) measurement, but its value is limited by the interference of anti-thyroglobulin antibodies (anti-Tg Ab). Recently thyroglobulin measurement in the wash out of fine-needle aspiration biopsy specimens (Tg-FNAB) is frequently used for differential diagnosis of recurrences/metastases. The aim of this study was the investigation of the diagnostic utility of Tg-FNAB compared with serum Tg. Materials and Methods: We enrolled 41 consecutive patients with thyroid cancer who were evaluated for Tg-FNAB between January 2007 and February 2008 retrospectively. We ruled out 6 patients who anti-Tg Ab positive (${\geq}$100 U/mL) in the RIA (BRAHMS anti-Tgn RIA 100Det; BRAHMS Aktiengesell schaft, Berlin, Germany). Serum Tg and Tg-FNAB were measured by immunoradiometric assay (BRAHMS Tg pluS RIA 100 Det; BRAHMS Aktienge sellschaft, Berlin, Germany). We evaluated for Tg-FNAB compared with serum Tg and corresponding cytological smear. To compare the values of the two the t-test was used. Results: Tg-FNAB values were significantly higher (median 1,060 ng/mL, range 0.2~434,000 ng/mL) than serum Tg (median 2.5 ng/mL, range 0.9~131 ng/mL) (p=0.0394). The rate of correspondence with Tg-FNAB between cytological result was 87.9% and 65.9% in the case of serum Tg. Tg-FNAB was positive in 28 (24 with positive and 4 with suspicious cytology). Of the remaining 13 patients with negative Tg-FNAB, 1 had suspicious and 12 had unsuspicious cytology. serum Tg was positive in 26 (17 with positive and 3 with suspicious and 6 with unsuspicious cytology), Of the remaining 15 patients with negative serum Tg, 8 was positive in cytological result and 1 had suspicious and 6 had unsuspicious cytology. Conclusions: Tg-FNAB measurement is more accurate with high sensitivity (87.9%) than serum Tg (65.9%). The Tg-FNAB was a useful predictor for detecting recurrences/metastases with serum Tg.