• Magazine of the Korean Society of Agricultural Engineers
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• v.36 no.4
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• pp.48-55
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• 1994

This study was performed to evaluate the engineering properties of the lightweight concrete using surlightweight aggregate foaming agent and high performance agent. The following conclusions were drawn. 1. The unit weight of type A, B and C concrete was 0.912t/m$^3$, 1.592t/m$^3$ and 1.070t/m$^3$, respectively. Specially, the unit weight of type A concrete was decreased 42% than that of the type B concrete. 2. The highest engineering property was measured in the lightweight concrete using high performance agent Also, the ratio of tensile and bending strength to compresive streng-th of the lightweight concrete was higher than that of the normal cement concrete. 3. The dynamic modulus of elasticity of the lightweight concrete was in the range of 2.86 x 10 5~9.86 x 10 5 kg/cm$^2$ which was approximately 300% than that of the normal cement concrete. 4. The ultrasonic pulse velocity of the lightweight concrete was in the range 2047~3394 n/sec, which was smaller than that of the normal cement concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.247-248
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• 2010

This study is of manufacturing artificial lightweight aggregates using industrial wastes. The ingredients for manufacturing lightweight aggregate were stone sludge and bottom ash for main materials, and steel slag(SS), glass abrasive sludge(GS) and blast furnace slag(BS) respectively for accessory material. Their precursors were sintered in the range of $1,050{\sim}1,150^{\circ}C$ for 5 min. The sintered results show that the lightweight aggregate with SS had low water absorption ratio and density at $1,150^{\circ}C$. There's a possibility that if GS is used more than the range of this study, GS can be manufactured lightweight aggregate. But it is judged that BS are incongruent to be used for a raw material of lightweight aggregate.

• Computers and Concrete
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• v.19 no.5
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• pp.515-526
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• 2017

Recent trend is to use the lightweight concrete in the construction industry because it has several advantages over normal weight concrete. The Lightweight concrete can be produced from the industrial waste materials. In South East Asian region, researchers are very keen to use the waste materials such as oil palm shell (OPS) and palm oil clinker (POC) from the palm oil producing industries. Extensive research has been done on lightweight concrete using OPS or POC over the last three decades. In this paper the aggregate properties of OPS and POC are plotted in conjunction with mechanical and structural behavior of OPS concrete (OPSC) and POC concrete (POCC). Recent investigation on the use of crushed OPS shows that OPSC can be produced to medium and high strength concrete. The density of OPSC and POCC is around 20-25% lower than normal weight concrete. Generally, mechanical properties of OPSC and POCC are comparable with other types of lightweight aggregate concrete. It can be concluded from the previous study that OPSC and POCC have the noteworthy potential as a structural lightweight concrete.

• Magazine of the Korea Concrete Institute
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• v.9 no.1
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• pp.165-172
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• 1997

Lightweight foamed concrete is a concrete which is lighter than conventional concree by mixing ptetoamed foam in cement slurry. The objectives of this study are to develop optimal prefoarneti lightweight foamed concrete with high lightness. high flowability and enough strength fol special use of structural application by using the polymer foam agent. By mixing the admixtures such as silica-fume and fly-ash and the industrial by-product such as styrofoam for the purpose of practical use of industrial waste, lightweight foamed concrete shich has better lightness. flowability and strength than the conventional prefoamed lightweight foamed concrete is developed. This paper presents extensive data on characteristics of compressive strength and flowability of the concrete manufactured with the different factors in mix design and also presents optimum mix proportion.

• Journal of the Korean Ceramic Society
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• v.46 no.6
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• pp.633-638
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• 2009

Lightweight materials were fabricated using glass abrasive sludge, bottom ash and slag powder in this study. This study tried to draw the correlation between physical properties and internal pore of lightweight material. The content of bottom ash and slag powder was from 10% to 50% and firing temperature from $760{^{\circ}C}\;to\;800{^{\circ}C}$ in rotary kiln. The lightweight material containing bottom ash or slag powder had a specific gravity of $0.21{\sim}0.70$ at particle size $2{\sim}4$ mm. Replacement ratio of the admixture increasing with specific gravity increased. Fracture strength of panel made with various lightweight materials was $32{\sim}55\;kgf/cm^2$ and flexural strength was $11{\sim}18\;kgf/cm^2$. Fracture strength increased by 72% and flexural strength was 63% compared with reference. Thermal conductivities of panel was $0.07{\sim}0.11W/m{\cdot}k$. The water absorption ratios of panel with lightweight materials containing bottom ash were $1.8{\sim}2.8$% and slag powder were $2.65{\sim}2.8$%. Excellent results on resistant of water absorption.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.57-60
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• 2006

This study proposes the physical properties of the hardened lightweight cement using the polyethylene tube and to make the fundamental data regarding a new lightweight concrete development. The aerated concrete is displaying various effects such as lightweight, insulation characteristic and it is coming to be widely applied the slab layer of apartment as an insulating material but currently the aerated concrete has many problems. Therefore, demonstrating similar property of former aerated concrete and improving the defects, developing new hardened cement is needed. In this study, we predict adopting possibility of hollow core polyethylene tube, as a material to make cement hardening containing a lot of void. So we changed the mixing ratio, a diameter and length of the polyethylene tube and improved the compressive strength and unit capacity weight of the lightweight cement hardening body. From the test results, we judge that the aerated concrete is a developmental possibility.

• Computers and Concrete
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• v.7 no.1
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• pp.53-62
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• 2010

Dredged silt from reservoirs in southern Taiwan was sintered to make lightweight aggregates (LWA), which were then used to produce high-performance lightweight aggregate concrete (HPLWC). The HPLWC was manufactured using different amounts of mixing water (140, 150, and 160 $kg/m^3$) and LWA of different particle densities (700, 1100, and 1500 $kg/m^3$) at different W/b ratios (0.28, 0.32, and 0.4). Results show that the lightweight aggregates of dredged silt taken in southern Taiwan perform better than the general lightweight aggregates. In addition, the HPLWC possessed high workability with a slump of 230-270 mm, and a slump flow of 450-610 mm, high compressive strength of over 40 MPa after 28 days of curing, good strength efficiency of cement exceeding $0.1MPa/kg/m^3$, low thermal conductivity of 0.4-0.8 $kcal/mh^{\circ}C$, shrinkage of less than $4.8{\times}10^{-4}$, and high electrical resistivity of above 40 $k{\Omega}-cm$. The above findings prove that HPLWC made from dredged silt can help enhance durability of concrete and provide and an ecological alternative use of dredged silt.

• Computers and Concrete
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• v.19 no.2
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• pp.121-126
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• 2017

This paper presents the effect of aggregate type on high temperature resistance of self-compacting mortars (SCM) produced with normal and lightweight aggregates like expanded perlite and pumice. Silica fume (SF) and fly ash (FA) were used as mineral additives. Totally 13 different mixtures were designed according to the aggregate rates. Mini slump flow, mini V-funnel and viscometer tests were carried out on the fresh mortar. On the other hand, bulk density, porosity, water absorption and high temperature tests were made on the hardened SCM. After being heated to temperatures of 300, 600 and $900^{\circ}C$, respectively, the tensile strength in bending and compressive strength of mortars determined. As a result of the experiments, the increase in the use of lightweight aggregate increased total water absorption and porosity of mortars. It is observed that, the increment in the usage of lightweight aggregate decreased tensile strength in bending and compressive strengths of mortar specimens exposed to high temperatures but the usage of up to 10% expanded perlite in mortar increased the compressive strength of specimens exposed to $300^{\circ}C$.

• Computers and Concrete
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• v.19 no.2
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• pp.203-210
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• 2017

The purpose of this paper is to evaluate the settlement of lightweight coarse aggregate of self-compacting lightweight concrete (SCLC) after placement of concrete on its final position. To investigate this issue, sixteen samples of concrete mixes were made. The water to cementitious materials ratios of the mixes were 0.35 and 0.4. In addition to the workability tests of self-compacting concrete (SCC) such as slump flow, V-funnel and L-box tests, a laboratory experiment was made to examine the segregation of lightweight coarse aggregate in concrete. Because of the difficulties of this test, the image processing technique of MATLAB software was used to check the segregation above too. Moreover, the fuzzy logic technique of MATLAB software was utilized to improve the clarity of the borders between the coarse aggregate and the paste of the mixtures. At the end, the results of segregation tests and software analyses are given and the accuracy of the software analyses is evaluated. It is worth noting that the minimum and maximum differences between the results of laboratory tests and software analyses were 1.2% and 9.19% respectively. It means, the results of image processing technique looks exact enough for estimating the segregation of lightweight coarse aggregate in SCLC.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.257-264
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• 2002

This study presents a life-cycle cost (LCC) effectiveness of a concrete with lightweight aggregate. A number of researchers have made their efforts to develop a lightweight concrete, since it is difficult to apply conventional concrete using general aggregate to heavy self-weight structures such as long span bridges. In this study, an optimum design for minimizing the life-cycle cost of concrete slab bridges is performed to evaluate the life cycle cost effectiveness of the lightweight concrete relative to conventional one from the standpoint of the value engineering. The data of physical properties for new concrete can be obtained from basic experimental researches. The material properties of conventional one are acquired by various reports. This study presents a LCC effectiveness of newly developed concrete, which is made by artificial lightweight aggregate. A number of researchers have made their efforts to develop a lightweight concrete, since it is difficult to apply conventional concrete using general aggregate to heavy self-weight structures such as long span bridges. From the results of the numerical investigation, it may be positively stated that the new concrete lead to, the longer span length, the more economical slab bridges compared with structures using general concrete.