• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.169-170
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• 2017

In this study, the adequacy evaluation of limestone for exterior use is presented. Major flaws of limestone for exterior use are reviewed. In addition, freezing-thawing test of the limestone specimens were performed. As a result, the limestone specimens was damaged by the freezing and thawing action for 300 cycle.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.163-164
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• 2022

Using the limestone powder as material that can substitute the clinker, it seems to get positive effect as filler and enhance workability of cement but the substitution amount and chemical properties of it can affect mechanical properties of cement. Thus, in this study, the effect limestone powder that has other properties on cement is evaluated. As a result, the workability enhancing effect was confirmed but deterioration of compressive strength was also checked. Later, with the view of workability, the experiment that the possibility of strength compensation by decreasing unit water weight of limestone powder cement is planned when the limestone powder is used.

• Journal of the Korean Recycled Construction Resources Institute
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• v.12 no.1
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• pp.102-109
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• 2024

In order to use limestone powder as a material for concrete, the mechanical and durability characteristics of cement matrices manufactured by varying the substitution rate were evaluated. In general, limestone powder did not contribute to the cement hydration reaction, so as a result of the compressive strength test of cement mortar using it, the compressive strength decreased as the substitution rate increased. However, as a result of evaluating the durability performance of cement mortar using limestone powder, such as chloride ion penetration resistance, carbonation resistance, and chemical attack resistance, small particles of limestone powder showed superior results compared to the unsubstituted control mortar due to the micro-filler effect of filling the fine pores inside the cement matrix. Therefore, limestone powder is expected to be used as an effective method for improving the durability of concrete. In this study, the durability was evaluated by changing the mixing amount of limestone powder to 0 %, 5 %, 10 %, and 15 %, but it is judged that it is necessary to study in more detail the effect on the durability by changing the end and mixing amount of limestone powder to various levels in the future.

• International Journal of Concrete Structures and Materials
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• v.4 no.2
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• pp.97-104
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• 2010

The crushed limestone sand is an abundant material in Tunisia, which induces many environmental problems. Indeed, available stocks of siliceous sand drastically decrease because of its massive use in hydraulic concrete. Some recent research works, carried out in Tunisia, concluded that crushed limestone sand may be used in concrete manufacture instead of siliceous sand traditionally used. In this context, an experimental study was achieved in order to quantify the influence of a partial or total substitution of siliceous sand by crushed limestone sand on hydraulic concrete performances. Preliminary chemical and physical tests on crushed sand indicated that it presented the minimum requirement for its use as aggregate in hydraulic concrete. 79 concretes were then prepared with siliceous sand, crushed limestone sand and a mix of the two sands. Their slump value and compressive strengths were measured on plain concretes. Complementary structural tests on reinforced concrete beam were also performed. The results proved that crushed limestone sand concretes showed workability and mechanical performances closed to those of siliceous sand concretes.

• Economic and Environmental Geology
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• v.13 no.1
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• pp.21-27
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• 1980

${\delta}^{13}C$ and ${\delta}^{18}O$ values were determined for the Paleozoic limestones (Great Linestone Series) from the Taebaegsan region and the age-unknown limestones (Janggun Formation) from the Janggun mine, Korea. Limestones of the Great Limestone Series exhibit a range of carbon isotopic composition from -4.5 +1.3‰ with a mean ${\delta}^{13}C$ value of -1.1‰, relative to the PDB standard, and of oxygen isotpic composition from +8.8 to +23.3‰ with a mean ${\delta}^{18}O$ value of +16.0‰, relative to the SMOW, falling into the normal marine limestone range according to Keith and Weber (1964), and Degens and Epstein(1964). Carbon isotopic composition of limestones of the Great Limestone Series becomes progressively lighter from Pungchon limestone of middle Cambrian age to mid-Ordovician Maggol limestone, possibly due to change in depositional environment in the Taebaegsan basin. Variation in isotopic composition of limestones from Hwajeol to Dumugal formation offers the possibility or deposition in shallow sea environment, in which fresh waters were added in several stages. Janggun limestone of unknown age may be corelated with the Paleozoic limestones of Great Limestone Series as infered from the istopic composition ranging from -2.8 to + 0.7‰ of ${\delta}^{13}C$ and +13.4 to +22.4‰ of ${\delta}^{18}O$.

• Journal of the Korean Ceramic Society
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• v.51 no.2
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• pp.132-137
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• 2014

The study was performed with low-grade limestone, which is used to make cement or is disposed of due to its low CaO content. In this study, the optimal condition of limestone with which to manufacture precipitated calcium carbonate (PCC) and limestone in fiber was determined through in-situ reactions. The best firing condition is with slaked lime with rapid cooling after 2 h of firing at $1000^{\circ}C$. In addition, the content of CaO can be increased by sorting the low-grade limestone using a 200 mesh filter, and the optical quality of old newspaper (ONP) was similar when using both low-grade and high-grade limestone. Also, controlling the particle size of PCC is an important factor pertaining to the optical characteristics of paper.

• Journal of the Korean Ceramic Society
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• v.51 no.6
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• pp.575-583
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• 2014

The flue gas desulfurization (FGD) process is currently the most effective process utilized to remove sulfur dioxide from stack gases of coal-fired plants. However, FGD systems use a lot of limestone as desulfurizing agent. In this study, we use limestone sludge, which is a by-product of the steel industry, to replace the desulfurizing agent of the FGD system. The limestone particle size is found to be unrelated to the desulfurizing rate; the gypsum purity, however, is related. Limestone sludge mixes with limestone slurry delivered at a constant rate in a desulfurizing agent with organic acid are expected to lead to a high desulfurization efficiency and high quality by-product (gypsum).

• Journal of the Korean Society of Environmental Restoration Technology
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• v.22 no.1
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• pp.47-59
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• 2019

This study was composed of four treatments [no treatment, phosphate + limestone layer treatment, phosphate + sodium bicarbonate + cement layer treatment, and phosphate + sodium bicarbonate + limestone layer treatment] for figuring out vegetation effects on the acid drainage slope. Treated acid neutralizing techniques were effective for neutralizing acidity and vegetative growth in order of [first: phosphate + sodium bicarbonate + limestone layer treatment, second: phosphate + sodium bicarbonate+cement layer treatment, third: phosphate + limestone layer treatment and fourth: no treatment] on the acid drainage slope. We found out that sodium bicarbonate treatment was additory effect on neutralizing acidity and increasing vegetaive growth besides phosphate and neutralizing layer treatments. In neutralizing layer treatments, Limestone layer was more effective for vegetation and acidity compared to cement layer treatment. Cement layer showed negative initial vegetative growth probably due to high soil hardness and toxicity in spite of acid neutralizing effect. Concerning plants growth characteristics, The surface coverage rates of herbaceous plants, namely as Lotus corniculatus var. japonicus and Coreopsis drummondii L were high in the phosphate + sodium bicarbonate + limestone layer treatment while Festuca arundinacea was high in the phosphate + sodium bicarbonate + cement layer treatment. We also figured out that soil acidity affected more on root than top vegetative growth.

• Journal of the Korea Concrete Institute
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• v.27 no.1
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• pp.3-9
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• 2015

In this study, hydration properties of ordinary Portland cement were examined, shown from a limestone and blast furnace slag alone or their mixture up to 10% as a minor mineral additives. As of setting time, it was identified that final setting became faster as the amount of limestone mixture increased, which showed limestone accelerated early hydration faster than blast furnace slag. This is because limestone did accelerate the hydration of alite. At the age of 3 days, limestone 5%-blast furnace slag 5% mixture had the highest compressive strength of mortar. It is because hydration acceleration of alite by limestone, and $Ca(OH)_2$ that was additionally formed by hydration acceleration of alite reacted with blast furnace slag, and as a result, additionally created C-S-H hydrate. Regarding the hydration properties by the age of 7 and 28 days, limestone 3%-blast furnace slag 7% of composited mixture showed the largest compressive strength, and in comparison with the 3 days in curing age. This period is when hydration reaction of blast furnace slag is active and the amount of hydrate depends on the amount of blast furnace slag mixture more than that of the limestone mixture. And in order to vitalize hydration reaction of blast furnace slag the amount of $Ca(OH)_2$ created has to increase, and thus, a small amount of limestone is necessary that can accelerate the hydration of alite. Therefore, after the age of 7 days, the fact that there were a large amount of blast furnace slag mixture and small amount of limestone mixture was effective to the strength development of ordinary Portland cement.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.440-448
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• 2023

Utilizing admixture, which is one of the raw material replacement method in the cement industry, is expected to be easily and quickly put to practical use as it is relatively more accessible than other methods. Among cement admixtures, limestone powder is reported to be able to improve cement performance through nucleation effects, chemical effects, and filler effects, so it is a material expected to be suitable as a cement admixture. Meanwhile, as high-quality limestone is depleted around the world, the use of limestone with clay or high magnesia (MgO) content is becoming increasingly inevitable. Therefore, in this study, we attempted to evaluate the suitability of limestone cement as a admixture by measuring the basic properties of limestone cement mixed with limestone of different qualities commonly used in Korea. As a result, the effect of alite reaction promotion was confirmed regardless of the chemical composition of the limestone binder. However, the dilution effect depending on the substitution amount was greater than the chemical composition. It is believed that normal-grade limestone can be used as a mixture as long as the limestone content in cement is within 15 % in this scope of study. In the future, we plan to evaluate the impact of the chemical composition of the limestone mixture through additional experiments depending on the chemical composition of cement.