• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.107-110
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• 1999

The objective of this study is to obtain characteristics of early age pore-structure and carbonation of concrete using ground granulated blast furnace slag (GGBFS). The durability of GGBFS concrete should be evaluated for wide use of the GGBFS. As for that evaluation, an analysis on early age pore-structure characteristics of GGBFS concrete are very important, Carbonation depths of GGBFS concrete, which are known to be larger than that of OPC, are different according to replacement ratios and fineness of slag. Because sea sand as fine aggregate is much used recently, it is also necessary to analyze characteristics of carbonation of GGBFS concrete. In this study, The micro-pore structure formation characteristics of GGBFS concrete are obtained through the test of GGBFS mortars with different fineness and replacement ratio of GGBFS. The carbonation of GGBFS concrete is also investigated by acclerated carbonation test for early age GGBFS concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.185-188
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• 2006

During the carbonation process in concrete, the rate of carbonation depends on porosity and moisture content of the concrete. For underground reinforced concrete structures, the interior concrete surface may be exposed to carbonation and the exterior concrete surface exposed to moisture due to wet soil or underground water. In this study, the permeability coefficients in mortar partially carbonated is derived as a function of carbonation depth and porosity of mortar by applying the so-called micro pore structure formation model (MPSFM) which was developed for the modeling of early-aged concrete. The permeability coefficient obtained from the micro-level modeling of carbonated mortar is verified with the results of accelerated carbonation test and water penetration test in cement mortar.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.193-196
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• 2005

In this study, the purpose is to suggest the data on mixing ratio which effects on the carbonation of concrete by replacing various admixture such as silica fume, fly ash, slag powder. Thus, we have experimented the accelerated test on the carbonation related to hardened body of the concrete which was admixed by slag powder, silica fume, fly ash and it was cured for 4 weeks in carbonation accelerator after 28 days curing water. The result of this experiment showed that carbonation speed increased highly when admixtures be used to replacing by growing of admixture ratio. especially, the test sample which was replaced with silica fume 15$\%$ and slag powder 40$\%$, was promoted highly to carbonation.

• 한국산업융합학회 논문집
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• 제23권6_2호
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• pp.1111-1117
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• 2020

In this study, the carbonation characteristics of concrete according to the mixture of OLED waste glass were evaluated. Replacement capacities of OLED waste glass were 0%, 10%, 20%, and 30% of cement, and they were named OG 0, OG 10, OG 20, and OG 30. As a result of the compressive strength test, OG 0 without replacing OLED waste glass showed high intensity until the 14th. However, the higher the replacement rate of OLED waste glass, the higher the compressive strength of 28 days. In addition, the speed of carbonation was faster with the higher the replacement rate of OLED waste glass, and the accelerated carbonation experiment was about three times faster than the natural carbonation test. In conclusion, the carbonation characteristics of OLED concrete are expected to be positive in terms of atmospheric CO2 absorption.

• 도시과학
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• 제11권1호
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• pp.21-28
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• 2022

Raman spectroscopy is effective to investigate functional groups via molecular vibration. The technique offers the structural information of compounds including subtle changes in the chemical composition of local atomic coordination without critical damage. Thus, the effect of carbonation on the hydration characteristics of Portland cement under pre-curing conditions for carbonation was investigated via Raman spectroscopy in the present study. Gaseous CO₂ was injected within 60 seconds, and the reaction time was varied from 0 minute to 90 minutes. The test results indicated that the Ca/Si ratio of C-S-H reduced immediately after mixing and then the C-S-H with a relatively high Ca/Si ratio coexisted as the reaction time increased. The calcium carbonates formed in the present study included calcite and amorphous calcium carbonates. The test results via Raman spectroscopy provide valuable information about the carbonation characteristics of OPC under pre-curing conditions for carbonation.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.783-786
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• 1999

The compressive strength of concrete is one of the most important properties in concrete structures. There are, two methods for the testing of concrete compressive strength in structure ; coring and nondestructive testing. The latter is more often used than the former in a view of time and expenses. The Nondestructive test methods used nowadays include Rebound Hammer test and Ultrasonic Pulse Velocity test. Carbonation through aging makes changes of the interior structure and the properties of concrete. It is well-known fact that the surface hardness of concrete is increased by its carbonation. This fact makes it difficult in estimating the compressive strength of concrete using Rebound Hammer test. This study aimed to quantitatively analyzed the effects of carbonation on results of the Rebound Hammer test.

• 콘크리트학회논문집
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• 제24권5호
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• pp.577-584
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• 2012

알칼리 활성슬래그(AAS)는 $CO_2$ 배출 부하가 큰 보통포틀랜드시멘트(OPC)의 가장 확실한 대체 재료로써 구조재로 이용하기 위해서는 내구성 평가 및 검증이 필요하다. 내구성 평가지표의 큰 비중을 차지하고 있는 것이 탄산화저항성인데, 알칼리 활성슬래그는 낮은 칼슘 함유량 때문에 OPC보다 탄산화 저항성이 약한 것으로 알려져 있다. 이 연구에서는 알칼리 활성슬래그의 모재료인 고로슬래그의 염기도(CaO/$SiO_2$)를 메카노-케미컬 합성법에 의해 조정하고, 조정된 염기도에 따라 수화생성물의 구성변화와 탄산화 전 후의 물리적 특성이 어떻게 변하는지 살펴보았다. 실험 결과 염기도가 높을수록 강도 증가와 탄산화 저항성이 향상되고, 탄산화 후 강도 저하가 개선되었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.89-91
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• 2012

The purpose of this study is to investigate the mechanical property and carbonation resistance of concretes using surface treated lightweight aggregate. In order to evaluate mechanical property and carbonation resistance, slump, compressive strength, and carbonation depth are tested. Slump of concretes using surface treated lightweight aggregate measured 120~125mm, which are lower than slump of NWAC. Compared to compressive strength of NWAC, compressive strength of concretes using surface treated lightweight aggregate showed a level of 82.8~95.9%. In carbonation resistance test, carbonation depth of concretes using surface treated lightweight aggregate measured 10.2~11.3mm, which are lower than carbonation depth of NWAC. As a result, it is found that compressive strength is decreased slightly but carbonation resistance is improved, in case of using surface treated lightweight aggregate.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.30-31
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• 2019

Carbonation of the root concrete reduces the durability of the reinforced concrete, and it is important to check the carbonation resistance of the concrete to ensure the durability of the reinforced concrete structure. In this study, a basic study on the prediction of carbonation progress was conducted by considering the mixing conditions of concrete using deep learning algorithm during the theory of artificial neural network theory. The data used in the experiment used values that converted the carbonation velocity coefficient obtained from the mixing conditions of concrete and the accelerated carbonation experiment into the actual environment. The analysis shows that the error rate of the deep learning model according to the Hidden Layer is the best for the model using five layers, and based on the five Hidden layers, we want to verify the predicted performance of the carbonation speed coefficient of the carbonation test specimen in which the exposure experiment took place in the real environment.

• 한국안전학회지
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• 제29권4호
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• pp.103-109
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• 2014

In this study, two types of water-soluble sulfur, LSA and LSB, were developed and the influence of the water-soluble sulfur on the mechanical properties and durability of concrete were experimentally evaluated. In order to evaluate mechanical properties and carbonation resistance of concrete with water-soluble sulfur, compressive strength test, flexural strength test, bonding strength test, and carbonation resistance test were performed. Compressive strength of only concrete with 1% LSA was increased while that of concrete with LSB was proportionally increased with the higher LSB dosage. On the other hand, flexural strength of concrete with LSA and LSB was increased by 12-41% and 36-74%, respectively. Carbonation resistance of concrete with water-soluble sulfur were increased by 25-66%. As a result, it should be noted that the water-soluble sulfur can not only solve the demerit of sulfur concrete but also offer the durability of sulfur concrete.