• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.05a
• /
• pp.131-136
• /
• 2002

In recent year, it has been investigated on the reduction of mass of structures for the purpose of the larger space and the economy with the industry developing very fast and qualitatively. So the purpose of this study is to investigate the manufacture of light weight concrete panel using the artificial light-weight aggregate as a part of the substitution of foamed styrene and polyurethane because of narrow allocable temperature zone in use. The compressive strength, flexural strength, unit weight, absorption test and thermal conductivity were practised at 3, 7 and 28 days after manufacturing the light-weight concrete lot the panel core: the filling ratio of continuous void was defied as 40%, 50%, and 60% and water-cement rate was 35, 40 and 45%. As a result of this, it was revealed that the mixture derived from filling ration of void of 50% and water-cement ratio 40% were developing the best properties of the others.

• Computers and Concrete
• /
• v.14 no.3
• /
• pp.247-262
• /
• 2014

Partial replacement of Portland cement by slag can reduce the energy consumption and $CO_2$ emission therefore is beneficial to circular economy and sustainable development. Compressive strength is the most important engineering property of concrete. This paper presents a numerical procedure to predict the development of compressive strength of slag blended concrete. This numerical procedure starts with a kinetic hydration model for cement-slag blends by considering the production of calcium hydroxide in cement hydration and its consumption in slag reactions. Reaction degrees of cement slag are obtained as accompanied results from the hydration model. Gel-space ratio of hardening slag blended concrete is determined using reaction degrees of cement and slag, mixing proportions of concrete, and volume stoichiometries of cement hydration and slag reaction. Furthermore, the development of compressive strength is evaluated through Powers' gel-space ratio theory considering the contributions of cement hydration and slag reaction. The proposed model is verified through experimental data on concrete with different water-to-binder ratios and slag substitution ratios.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.8 no.3
• /
• pp.43-52
• /
• 1988

In this paper, three kinds of proportioning method on concrete mixes containing fly ash as an admixture were compared and investigated. As the test results for relationships between substitution ratio of fly ash, water-binder ratio, ages and strength besides the proportioning methods and workability of fresh concrete beneficial reference data to estimate quality of domestic fly ash were atained.

• Journal of the Korean Society of Food Culture
• /
• v.33 no.1
• /
• pp.70-77
• /
• 2018

This study examined the quality characteristics of waffles made with coconut extract. Waffles were prepared with the substitution of 25, 50, 75, 100, and 125% of coconut extract. The viscosity of the batter tended to increase with increasing ratio of coconut extract, whereas the spreadability measures were not changed significantly. The baking loss rates tended to increase with increasing ratio of coconut extract while the moisture contents were not changed significantly. The L-value and b-value decreased but the a-value increased. TPA showed that the hardness, springiness, chewiness, cohesiveness, and gumminess tend to increase with increasing amount of coconut extract while the resilience was not changed significantly. The results of the sensory evaluation showed that waffles made with 100% coconut extract were the most preferable in appearance, flavor, taste, texture, and overall acceptability.

• Carbon letters
• /
• v.4 no.4
• /
• pp.175-179
• /
• 2003

It is well established that halogenated fullerene derivatives act as synthetic intermediates for further substitution via replacement with nucleophlies. In the present work, systematic studies were carried out on the synthesis of bromofullerenes under different experimental conditions. The effect of reaction time on the product formed was observed. We observed the formation of new compound of bromofullerenes in a different stoichiometric ratio i.e., $C_{60}Br_{14}$; in addition to previous reported bromofullerenes in the stoichiometric ratio of $C_{60}Br_6$, $C_{60}Br_8$, and $C_{60}Br_{24}$. The new derivative of bromofullerene was isolated and well characterized by various analytical techniques like FT-IR, TGA, DSC, and elemental analysis. In this paper, detail of the synthesis and characterization of the bromofullerene prepared are described. The yields obtained were better than those reported previously.

• Journal of the Korean Ceramic Society
• /
• v.33 no.2
• /
• pp.135-142
• /
• 1996

Fly Ashes which are produced from coal-fired powder plants and classified as general waste can be used as raw materials for bricks and tiles because of their compositional similarity with clays. There was a limit of substituting fly ash for clay because plasticity decreased with increasing fly ash additions. Accordingly this study tried to suggest a feastibility of enhancing the substitution ratio by controlling the interfacial properties of fly ash. The slip with 1:1 volume ratio showed that best dispersive characteristics under the condition of pH 2 Filter pressed cakes made of pH 2 slips also showed better plastickity than those of untreated ones. of pH 2 Filter pressed cakes made of pH 2 also shwoed better plasticity than those of untreated ones.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1996.10a
• /
• pp.148-153
• /
• 1996

Concrete with ground granulated blast-furnace slag can be affected by frost attack because the reaction of hydration is slow at the early age. In this study, therefore, the freezing and thawing test has been carried out to investigate the freezing and thawing resistance on concrete with ground granulated blast-furnace slag. The freezing and thawing test has been performed on concrete a blended cement, which was substituted by ground granulated blast-furnace slag with 4 kinds of ratio (non-admixture, 20%, 40% and 60%). And also tested on concrete added the AE agents to the concrete of same mix proportion to search the improvement effects about the resistance. As a result, the freezing and thawing resistance showed a tendency of reduction in proportion to the increase of the substitution ratio. For non-AE concrete, resistances of the freezing and thawing were very poor as the durability index indicated less than 5.8%. For AE concrte, resistance of the freezing and thawing were excellent as the durability index indicated more than 80.9%.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.05b
• /
• pp.193-196
• /
• 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.

• Journal of Ocean Engineering and Technology
• /
• v.14 no.1
• /
• pp.74-79
• /
• 2000

The purpose of this paper is to recycle coal ash as structural backfill materials from electric power plants. Two million tons of coal ash are produced annually. The laboratory test was executed for the basic compatibility as substitution for structural backfill materials and the optimal mixture ratio(fly ash : bottom ash) was decided. In addition the model test was performed using medium scale earth pressure model with small size earth pressure cells model box data logger and some other apparatuses. Mixed coal ash and excellent backfill materials(coheisonless soil SW) were compared in the view of lateral earth pressure variation depending on wall displacement. The reduction of earth pressure when coal ash was used as a bockfill material was monitored comparing to that of cohesionless soil. the cost and environmental pollutants by treating coal ash can be reduced through developing the recycling technology.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.11a
• /
• pp.805-808
• /
• 2006

At the present time, as part of the movement of natural resource conservation, there have been doing many recycling research works for wasted concrete, etc. In this study, we carried out an experiment for using crushed waste glass as a binder. It dealt with comparative analysis of the engineering properties of mortar containing crushed waste glass through a physical experiment. The experimental variables are the crushed waste glass powder substitution ratio(C-type : $0{\sim}25%$, B-type : $0{\sim}50%$, F-type : $0{\sim}100%$). According to this study, As the substitute of waste glass powder increases, air content and unit weight, the compressive strength decreases exactly proportion to the substitute ratio of waste glass powder. if, when waste glass is substituted as the binder, it is necessary to use an admixture.