• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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• pp.230-231
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• 2017

The addition of a limestone filler(LF) to fill into the voids between cement and aggregate particles can reduce the cementitious paste volume. This paper aim to evaluate the influence of LF contents on the hydration kinetics and compressive strength. Hydration kinetics were evaluate using heat of hydration, ignition loss and thermal analysis. The heat of hydration was measured using Isothermal Calorimetry. The degree of hydration was measured using ignition loss. Hydration product analysis was carried out by Thermal Gravimetric and Differential Thermal Analysis. The results show that the addition of LF reduces not only the initial setting time and heat of hydration peak, also degree of hydration and rate of strength development at early age increase with the addition of LF. It can be concluded the LF fills the pore between cement particles due to formation of carboaluminate, which may accelerate the setting of cement pastes.

• Bulletin of the Korean Chemical Society
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• 제33권2호
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• pp.426-432
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• 2012

The activity of an antimicrobial peptide, protegrin-1 (PG-1), on lipid membranes was investigated using solidstate NMR and a new sampling method that employed mechanically aligned bilayers between thin glass plates. At 95% hydration and full hydration, the peptide respectively disrupted 25% and 86% of the aligned 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphotidylcholine (POPC) bilayers at a P/L (peptide-to-lipid) ratio of 1/20 under the new experimental conditions. The kinetics of the POPC bilayers disruption appeared to be diffusioncontrolled. The presence of cholesterol at 95% hydration and full hydration reduced the peptide disruption of the aligned POPC bilayers to less than 10% and 35%, respectively. A comparison of the equilibrium states of heterogeneously and homogeneously mixed peptides and lipids demonstrated the importance of peptide binding to the biomembrane for whole membrane disruption.

• 한국건축시공학회지
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• 제20권4호
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• pp.321-330
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• 2020

지오폴리머의 반응성은 원재료의 구성성분 및 Si/Al비, Na/Al비, 물-결합재비, 비정질 요소 등을 고려하여 명확한 메커니즘을 규명하는 것은 매우 중요하다. 따라서 원재료 및 알칼리 활성화제의 구성성분을 고려한 %Na₂O, M_s는 반응성을 결정하는 중요한 요소가 된다. 하지만 다수의 연구에서는 알칼리 활성화제의 농도와 양생 조건 등의 기본적인 요소만을 고려하는 한계점을 나타내고 있다. 따라서 본 연구에서는 %Na₂O, Ms 및 고로슬래그 미분말의 혼입량에 따른 지오폴리머 페이스트의 강도특성, 반응열, 길이변화, 미세구조 분석을 실시하였다.

• Computers and Concrete
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• 제11권4호
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• pp.271-289
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• 2013

In this research, a developed microstructural model of cement particles was presented to describe the cement hydration procedure. To simplify the hydration process, the whole hydration was analyzed in a series of sub-steps. In each step, the hydration degree, as well as the microstructural size of the hydration cell, was calculated as a function of the radius of the unreacted cement particles. With the consideration of the water consumption and the reduction of the interfacial area between water and hydration products, the micro-level expressions of the cement hydration kinetics were established. Then the heat released and temperature history of the concrete was carried out with the hydration degree obtained from each sub-steps. The equivalent age method based on the Arrhenius law was introduced in this research. Based on the equivalent age method, a maturity model was applied to describe the evolution of the mechanical properties of the material during the hydration process. The finite element program ANSYS was used to analyze the temperature field in concrete structures. Then thermal stress field was calculated using the elasticity modulus obtained from code formulate. And the risk of thermal cracking was estimated by the comparison of thermal stress and concrete tensile strength.

• 한국세라믹학회지
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• 제31권5호
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• pp.538-542
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• 1994

The kinetics and mechanism on the hydration of granulated blastfurnace slag-sodium silicate systems were studied by ignition loss, unreacted slag determination, XRD, DTA and SEM(EDS). From this experiment the following results were obtained. The amount of slag reaction was increased with the content of sodium silicate and also C-S-H, C4AH13, and C2ASH8 were formed to be the main products up to 28 days of hydration. Sodium silicate was not only an activator for slag hydration but also a binder in the hydration. The amount of slag reaction activated by sodium silicate was a nearly same for Ca(OH)2 activated slag, but it was smaller one than that activated by NaOH. However there was no difference in hydration products.

• 한국식품조리과학회지
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• 제7권2호
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• pp.25-40
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• 1991

Five-brown-rice-variety, Akibare, Odaebyeo, Taebaegbyeo, Nonglim Na 1 and Hankangchalbyeo, was prepared and examinated the hydration kinetics and the cooking qualities. Before the hydration the L/W ratio of raw Taebaegbyeo was the biggest value among the five brown rices. The water uptake was directly proportional to the square root of soaking time. During the hydration water uptake of high yielding brown rices was bigger than those of traditional brown rices among the nonglutenious varieties but waxy brown rices were not. Generally volume increase constant was directly proportional to the water uptake constant, which were different a little with brown rices was hydrated which was inversed proportional to the water uptake degree. According to the instrumental result using the rheometer of cooked brown rice with increased soaking times that was decreased the hardness and was increased the adhesiveness. The sensory evaluation test indicated that the hardness and the stickiness value of cooked brown rices were proper after 15-hour-soaking time and it was identical result to the instrumental result using the rheometer.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.834-839
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• 2003

Previous research has been conducted on an ultrasonic wave reflection method that utilizes a steel plate embedded in the concrete to measure the reflection loss of shear waves at the steel-concrete interface. The reflection loss has been shown to have a linear relationship to compressive strength at early ages. The presented investigations continue this research by examining the fundamental relationship between the reflection loss, measured with shear waves, and the hydration kinetics of Portland cement mortar, represented by dynamic elastic moduli, compressive strength and degree of hydration. Dynamic elastic moduli are measured by fundamental resonant frequency and degree of hydration is determined by thermogravimetric analysis. The water/cement ratio was varied for the tested mixture compositions. The results presented herein show that compressive strength, dynamic shear modulus and degree of hydration have a linear relationship to the reflection loss for the tested mortars at early ages.

• Advances in concrete construction
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• 제6권6호
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• pp.659-677
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• 2018

The use of some superplasticizers in the production of mortar or concrete influences the hydration kinetic and the amount of total heat. This results in a modification of some properties, namely mortar workability, mechanical strength and durability. Three superplasticizers were used; a polynaphthalenesulfonate (PNS), a melamine resin (PMS) and a polycarboxylate (PC). They have been incorporated into various amount in a standardized mortar based on limestone cement. The aim of this study was to evaluate the rheological, mechanical and Calorimeters properties of this mortar. This will select the most compatible product and more able to be used depending on the climate of the country and the cement used. The PNS is incompatible with this type of cement registering a decrease of strength but the PMS and the PC modify the kinetics of hydration with significant heat generation and improved mechanical strength. The measured heat flow is significantly influenced by the type and dosage of superplasticizer especially for low dosage. Hydration heat and compressive strength of the different mixtures can be evaluated by determining their ultimate values and ages to reach these values where the correlation coefficients are very satisfactory.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 추계총회,초청강연,특별강연,연구발표회
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• pp.60.2-60
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• 2000

• 한국식품과학회지
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• 제15권2호
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• pp.136-140
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• 1983

도정수율별 보리의 수화특성(水和特性)을 $20{\sim}60^{\circ}C$ 범위에서 조사하고 속도론적으로 해석하였다. 흡수량(吸水量)은 수화시간(水和時間)의 평방근에 비례하였으며 흡수양상(吸水樣相)은 흡수량(吸水量) $0.45{\sim}0.55g\;H_2O/g$ solid 이후에서 변화하였다. 수화속도(水和速度)는 도정수율 50>70>95>90%>무도정맥의 순서였으며 수화온도(水和溫度)가 높을수록 증가하였다. 이 때 곡립내부(穀粒內部)로의 물의 확산도(擴散度)는 Arrhenius방정식에 의거하여 변화하였으며 활성화에너지는 도정맥의 경우 $6.9{\sim}9.5Kcal/mole$, 무도정맥의 경우 11.6Kcal/mole이었다.