• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.713-718
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• 1998

This paper deals with the consistency of fresh lightweight polyester mortars as high-performance or multifunctional building materials. Fresh lightweight polyester mortars using an unsaturated polyester resin, lightweight fillers and aggregate are mixed with various mix proportions, and tested for slump-flow and slump as a measure of consistency. At 10, 20 and 3$0^{\circ}C$, the influences of mix proportioning factors on the slump-flow and slump of the lightweight polyester mortars are examined, and the empirical equations for the slump predictions are successfully proposed.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.255-256
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• 2010

I think application properties to lightweight concrete of Chinese lightweight Aggregate will be considered according to the Grain Size, and shows by a reference data for efficient utilization of Chinese lightweight Aggregate to settle the problem that self-weight of concrete is excessive.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.05a
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• pp.91-96
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• 2002

This study is to investigate the insulation performance of lightweight concrete using recycled lightweight aggregate, to develop lightweight concrete products which have an excellence on the insulation performance are satisfied with properties of building materials. As a result of this study, recycled EPS aggregate is considered to have an independent pores which is closed by dense partitions. So, it is showed that the insulation performance of lightweight concrete using recycled EPS aggregate are excellent. Especially, in the case of lightweight concrete under conditions of replacement ratio over 100%, it is considered that insulation performance is very excellent as thermal conductivity is showed about 0.2kcal/mh$^{\circ}C$. According to considering the relation between ultrasonic pulse velocity, unit weight and thermal conductivity through the graph, the result of relation between ultrasonic pulse velocity, unit weight and thermal conductivity on the graph expressed their high interaction shown as direct proportion on the graph. So that it is possible to extract the insulation performance of lightweight concrete using recycled EPS aggregate by ultrasonic pulse velocity and unit weight.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.04a
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• pp.67-70
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• 2007

As construction industry is requiring competitive power and technique in national construction market with rapid fluctuation of construction environment and development, requirements upgrading performance in construction materials are increasing. But, national lightweight aggregate and lightweight concrete's inappropriateness when produced are also increasing. And there are not international standard of aggregates in using these construction materials because standards and characteristics of aggregate in each countries are different. Therefore, in this study, lightweight aggregate acquired due to wide range of use is tested and mixed for concrete to gain practicality and set the authorized manual in international. Also, basic data will be proposed to set a standard for concrete by analyzing lightweight aggregate characteristics. When lightweight aggregate absorptivity is high, concrete shows low strength and when it's density is low, concrete shows low weight of unit volume. Furthermore, compressive strength of lightweight aggregate is steep in first and longtime material age is tendency to cause low strength increasing rate.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.179-180
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• 2016

This study has a purpose of producing precast concrete for rapid construction of urban railway system. However, previous precast concrete has problem of its weight itself and there has been a keen interest in effect of carbon emission reduction and eco-friendly in our society. Therefore, in order to solve these two problems, we are about to produce precast concrete using lightweight aggregate and eco-lightweight concrete, with which much mineral had been replaced. As a result, we could confirm that it was possible to produce RMC B/P production satisfying the requirement performance of eco-lightweight concrete, which is replaced with a great amount of mineral for reduction of precast concrete's weight and environmental performance. Also, by confirming the possibility of producing precast concrete which lightweight concrete is used, if producing precast concrete by using eco-lightweight concrete, it would be effective to avoid destruction of environment and much useful to use multiple tower crane when constructing. Afterward, we will proceed our study by constructing precast concrete at which eco-lightweight concrete is used for continuous quality improvement.

• Journal of the Korea Institute of Building Construction
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• v.13 no.3
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• pp.202-208
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• 2013

The method used to test lightweight aggregate concrete for its resistance to freezing and thawing is different in each country. In Korea, the method of KS F 2456 on normal concrete is adopted for lightweight aggregate concrete, while the testing method of ASTM C 330 lightweight aggregates for structural concrete is used in the majority of overseas countries. In this study, we identified differences between KS F 2456 and ASTM C 330 in terms of the testing method for freezing and thawing resistance, and we studied the influence of this on the freezing and thawing resistance of lightweight aggregate concrete. The results of this study were as follows: Blocked lightweight aggregates had a slight collapse of shape and lost weight by repeated freezing and thawing, but unblocked lightweight aggregates were badly collapsed. And while the freezing and thawing resistance tests of normal concrete showed similar results despite the difference in the KS and ASTM testing method, the results for lightweight aggregate concrete were very different. So the KS test method shows evaluation results that are much lower than the ASTM test method.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.559-566
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• 2010

Fifteen lightweight concrete mixes were tested to evaluate the effect of maximum size of coarse aggregate and the replacement level of natural sand on the various properties of fresh lightweight concrete. The different properties, such as water absorption against the elapsed time, pore size distribution and micro-structure of lightweight aggregates used, influencing on the workability of fresh concrete were also measured. Test results showed that the initial slump of lightweight concrete decreased with the increase of the replacement level of natural sand. The slump of all-lightweight concrete sharply decreased by around 80% of the initial slump after 30~60 minutes. The air content and bleeding rate of lightweight concrete were significantly affected by the replacement level of natural sand as well as the maximum size of coarse aggregates. Empirical equations recommended in ACI 211 and Korea concrete standard specifications underestimated the air content of the lightweight concrete, indicating that the underestimation increases with the decrease of the replacement level of natural sand. In addition, equations to predict the air content and bleeding rate of lightweight concrete were proposed based on the test results.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.5
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• pp.551-557
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• 2010

The purpose of this study is to estimate experimentally the flexural behavior, capacity and validity of existing regulation of net tensile strain in lightweight concrete beams and polymer modified lightweight concrete beams. One normal weight concrete beam and four lightweight concrete beams, three polymer modified lightweight concrete beams were constructed as same figure and attempted to evaluate the difference of strength and ductility in specimens of different net tensile strain in extreme tension steel. Test results are indicated in terms of load-deflection behavior and ductility index. As the value of net tensile strain increased, the flexural strength and stiffness of specimen decreased but ductility index increased in both of lightweight concrete beams and polymer modified lightweight concrete beams. It is considered that to achieve similar ductility index of normal weight concrete, net tensile strain in extreme tension steel should exceed 0.005 for lightweight concrete beam and polymer modified lightweight concrete beam.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.141-142
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• 2015

This literature study is focused on the improvement of lightweight concrete in perspective of foaming agent. Lightweight concrete is the cured concrete as putting required amount of foaming agent to slurry which is a mixture of a certain amount of cement, sand, and water. It has lower density than general concrete, because foaming agent disintegrates numerous bubbles evenly and independently. Thus, it is capable of lightening the weight and great for sound absorption and insulation, In foreign countries, studies for structural lightweight concrete mainly of tunnel grouting and weight lightening of heavy structures are going along actively. Domestically, exterior panel and ALC blocks are alternatively used for flooring. Therefore, this research consider improvement of lightweight concrete in perspective of foaming agent with foundation study.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.640-643
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• 2004

Synthetic lightweight aggregates are manufactured with recycled plastic and fly ash with 12 percent carbon. Nominal maximum-size aggregates of 9.5mm were produced with fly ash contents of 0 percent, 35 percent, and 80 percent by total mass of the aggregate. An expanded day lightweight aggregate and a normal-weight aggregate were used as comparison. Mechanical properties of the concrete determined included density, compressive strength, elastic modulus, and splitting tensile strength. Compressive and tensile strengths were lower for the synthetic aggregates; however, comparable fracture properties were obtained. Relatively low compressive modulus of elasticity was found for concretes with the synthetic lightweight aggregate, although high ductility was also obtained. As fly ash content of the synthetic lightweight aggregate increased, all properties of the concrete were improved.