• Advances in concrete construction
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• v.5 no.6
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• pp.575-586
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• 2017

The disposal of polythene waste and fly ash is causing serious threat to the environment. Aim of this study is to decrease environmental pollution by using polythene waste and fly ash in concrete. In this study, cement was partially replaced with 0%, 5%, 10%, 15% and 20% fly ash (by weight) and plastic waste was added in shredded form at 0.6% by weight of concrete. The specimens were prepared for the concrete mix of M25 grade and water to cementitious material ratio (w/c) was maintained as 0.45. Fresh concrete property like workability was examined during casting the specimens. Hardened properties were found out by carrying out the experimental work on cubes, cylinders and beams which were cast in laboratory and their behavior under test were observed at 7 & 28 days for compressive strength and at 28 days for density, flexural strength, dynamic modulus of elasticity, abrasion resistance, water permeability and impact resistance. Overall results of this study show that addition of 0.6% (by weight of the concrete) plastic waste with 10% (by weight of cement) replacement of cement by fly ash result an improvement in properties of the concrete than conventional mix.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.99-100
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• 2012

Aggregate thermal properties and cooling methods are most important to evaluate the residual mechanical properties of concrete. In this study, we evaluate the residual mechanical properties of concrete according to the aggregate type and cooling method. We use the normal weight aggregate and light weight aggregate which have different thermal properties. After heating to the target temperature, we evaluate the mechanical properties according to the slow and fast cooling condition. As a result, normal weight aggregate concrete has higher effectiveness of cooling conditions than light weight aggregate concrete.

• Journal of Ocean Engineering and Technology
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• v.4 no.1
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• pp.71-80
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• 1990

We experimented the physical property of the porous concrete by changing the water cement ratio, when the aggregate ratios are 1:5 and 1:7 separately. And then we received the results as follows. The bigger, the coarse grading of the porous concrete is, the more sensitive to the water cement ratio, the porous concrete becomes. And if we think over its compressive strength, the coarse aggregate which has 5-15mm width is most appropriate. So we concluded that when its compressive strength, permeability coefficient and its unit weight are $50kg/cm^{2}3cm/sec$ and $1900kg/m^{3}$ respectively, the water cement ratio which has 35-37% width is most appropriate, too. And its compressive strength and unit weight show that they are about a quarter and three quarters respectively about the conventional concrete.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.4
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• pp.75-81
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• 1997

This study was performed to evaluate the engineering properties of surlightweight polymer concrete using synthetic lightweight aggregate. The following conclusions were drawn; 1. The unit weight was in the range of 0.849~0.969t/$m^3$, the unit weights of those concrete were decreased by 58 ~ 63% than that of the normal cement concrete. 2. The highest strength was achieved by $P_1$, and compressive strength was increased by 93% and bending strength by 364% than that of the normal cement concrete, respectively. 3. The ultrasonic pulse velocity was in the range of 2, 346~2, 702m/s, which was low compared to that of the normal cement concrete. 4. The dynamic modulus of elasticity was in the range of $1.561{\times} 10{^5}~1.916{\times} 10{^5}kgf/cm^2$, which was approximately 52~98% of that of the normal cement concrete. 5. The compressive and bending strength were increased with the increase of unit weight. But, the dynamic modulus of elasticity and ultrasonic pulse velocity were decreased with the increase of unit weight.

• Structural Engineering and Mechanics
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• v.62 no.5
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• pp.651-661
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• 2017

This paper presents an experimental study of bond-slip behavior of reinforced lightweight aggregate concrete (LC) and normal weight concrete (NC) with embedded steel bar. Tests were conducted on tension-pull specimens that had cross-sectional dimension with a reinforcing bar embedded in the center section. The experimental variables include concrete strength (20, 40, and 60 MPa) and coarse aggregate type (normal-weight aggregate and reservoir sludge lightweight aggregate). The test results show that as concrete compressive strength increased, the magnitudes of the slip of the LC specimens were greater than those of the NC specimens. Moreover, the bond strength and stiffness approaches zero at the loaded end, or close to the central anchored point of the specimen. In addition, the proposed bond stress-slip equation can effectively estimate the behavior of bond stress and steel bar slipping.

• Proceedings of the Korean Institute of Building Construction Conference
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• v.y2004m10
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• pp.59-63
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• 2004

In recent days. it is necessary to find environment-friendly way of diposing industrial waste and reclying system. So this study will analyze the property of Porous concrete improved by concrete waste powder and recycled lightweight aggregate and then suggest the ways of reclying. The method deals with experimenting unit weight of capacity. thermal conductivity, compression and ultrasonic pluse velocity. Considering the relation between ultrasonic pluse velocity and unit weight & thermal conductivity through the graph. the result of relation between ultrasonic pluse velocity and unit weight & thermal conductivity on the graph expessed their high interaction shown as direct proportion on the graph. Recycled Porous concrete merits lightweight and adiabatic. Therefore. we will expect that the current using ALC and Recycled Porous concrete has be similar thermal conductivity.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.177-180
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• 2008

Recently, the research of FRP bar as an alternative reinforcing material in reinforced concrete structures has increased to get an innovative solution to the corrosion problem. In addition to the noncorrosive nature of FRP materials, they also have a high strength-to-weight ratio. Therefore, when light weight concrete reinforced with FRP bar is used in marine environment, for instance floating structures, some advantages can be expected. But researches for the light weight concrete structure using FRP bar as a flexural reinforcement are limited to date. In this paper, the concrete shear contribution of the light weight concrete beam reinforced with GFRP bar was studied. Experiment for beams varying concrete compressive strengths and flexural reinforcement ratios was conducted and analysed. The test results showed that 75% of values obtained from proposed equation in preceding research were well agreed with the test results and were better results than the one predicted by the ACI 440.1R-06 code.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.416-421
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• 1997

This study was conducted to evaluate durability of high-strength light-weight aggregate concretes which are increasingly demanded recently. Two different artificial light-weight aggregates were used and two levels of high-strength concretes were made using w/c of 33% and 37% for target strength of 500kg/$\textrm{cm}^2$ and 400kg/$\textrm{cm}^2$, respectively. Cylinder specimens($\phi$=10cm and h=20cm) were made and treated with freezing-and-thawing(F/T) cycle at $-18^{\cire}C$ and $4^{\cire}C$. Dynamic modulus of elasticity and surface condition were evaluated with F/T cycle increase. The results showed that durability of the light-weight aggregate concretes was worse than that of conventional concrete, and the light-weight high-strength concrete with w/c=37% had the better durability than the one with w/c=33%.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.205-206
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• 2011

Inorganic Polymer Concrete, a type of Alkali activated cement and concrete, is known for various excellent performances, especially for better performance in the area of high temperature heat resistance(thermal characteristic) than portland cement concrete.In this study, light weight concrete panel was manufactured using this Inorganic Polymer Concrete and then evaluated for fire resistance with a small-scale heating furnace. Since the result showed excellent fire resistance, it is considered usable for manufacturing fire resistant concrete panel wall.

• Computers and Concrete
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• v.29 no.6
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• pp.361-374
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• 2022

On the premise of ensuring that the automatic and quantitative discharging function of concrete conveyors is met, the accuracy of the weight forecast by the mathematical model of the screw conveying volume is improved, and the error of the weight of the concrete parts and the accumulation thickness is reduced. In this paper, the discrete element method (DEM) is used to simulate the macroscopic flow of concrete. Using the concrete discrete element model, the size of the screw conveyor is set, and establish the response model between the influencing factors (process and structure) and the concrete mass flow rate according to the design points of the screw discharging experiment. The nonlinear data fitting method is used to obtain the volumetric efficiency function under the influence of process and structural factors, and the traditional screw conveying volume model is improved. The mass flow rate of concrete predicted by the improved mathematical model of screw conveying volume is consistent with the test results. The model can accurately describe the conveying process of concrete and achieve the purpose of improving the accuracy of forecasting the weight of discharged concrete.