• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.561-564
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• 2008

Concrete is considered to be one of the excellent and versatile shielding material and is widely used for the radiation shielding material. Specially, heavyweight(or high density) concrete is used in counter weights of bascule and lift bridges, but it is generally used in radiation shielding structures and differ from normal weight concrete by having a higher density and special compositions to improve its attenuation properties. Thorough examination and evaluation of heavyweight aggregate sources are necessary to obtain material suitable for the type of shielding required. Therefore, this paper aims to study mechanical properties of heavyweight concrete by using normal cement, natural and heavyweight aggregate.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.577-580
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• 2008

This paper was discussed about in-site application of heavyweight(or high density) concrete. Heavyweight concrete was placed with the method of conventional. Placement of conventionally mixed heavyweight concrete is subject to the same considerations of quality control as normal density concrete, except that it is far more susceptible to variations in quality due to improper handling. It is particularly subject to segregation during placement. Segregation of heavyweight concrete results not only in variation of strength but, far more importantly, in variation in density that are intolerable for work this type, since this adversely affects shielding properties. Heavyweight concrete materials and heavyweight concrete should be sampled and tested prior to and during construction to insure conformance with applicable standards and specifications.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.345-352
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• 2017

Heavy weight concrete can be used in marine concrete structure to improve resistance against high wave energy. However, heavy weight aggregate, which is an indispensable material for heavy weight concrete, is difficult to be supplied in large quantities because its use is limited due to its high cost. In this work, the applicability of heavy weight by-products, copper and 3 month aged steelmaking slags, were evaluated as sources of heavy weight aggregate for marine concrete structures. Experimental results showed that copper slag was found to be a stable material for marine concrete structure. However, 3 month aged steelmaking slag showed significant expansion by $80^{\circ}$ water immersion test and ASTM C 1260 test. In addition, depth of chloride ion penetration in concrete was higher at which steelmaking slags were located. It was associated with porosity of steelmaking slag, and for this reason, steelmaking slag was not found to be suitable for marine concrete structure.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.785-788
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• 2008

This study is focused on applying heavyweight concrete to ballast used to have stability of a ship. Generally, heavyweight concrete is made from a high density aggregate like magnetite or limonite. However, these materials are hard to obtain them from relevant companies and so expensive. Therefore, this study plans to product heavyweight ballast concrete which is easy to obtain by recycled iron slag. Heavyweight ballast concrete isn't required to meet some compressive strength in use, but it is required to have high flowable and 2.7t/m3 of bulk density to fill the ballast tank densely. The designed field mix proportion of concrete based on the results of pre-experiment shows it can control the temperature crack and has superior chloride corrosion resistance after conducting chloride corrosion experiment. Also, it is prefer that before airtightness voltile corrosion inhibiter(VCI) is added in airtight space of shipyard.

• Journal of the Korea Institute of Building Construction
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• v.17 no.6
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• pp.483-492
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• 2017

Recently, the coastal area has become the popular place for infrastructure development. To provide a beautiful scenary of costal area to nearby facilities without any hinderance, and also to protect those facilities from the sea water overflow, it is necessary to develop a new type of wave dissipating block, which is a turning wave block. It is noticeable that the top of the turning wave block is flat and thus can provide spaces for various purposes. However, the unit weight of the block decreases due to the presence of pipeline that is installed for turning the direction of the waves. In order to mitigate such problem, a heavyweight concrete needs to be used to increase the resistance against tidal waves. The copper slag and magnetite were used as a source of fine and coarse aggregate, respectively. The 28 day compressive strength of concrete incorporating ordinary and heavyweight aggregate did not show significant differences. It should be noted that the chloride ion penetration resistance was evaluated using NT-BUILD 492 rather than ASTM C 1202 method because concrete incorporating magnetite as a coarse aggregate showed excessive current flow by ASTM C 1202 method. According to the results from NT Build 492 method, which uses the penetration depth of chlorine ions to obtain chloride ion diffusivity, the heavyweight concrete incorporating the copper slag and the magnetite showed the best resistance against the chloride ion penetration. Therefore, it is reasonable to say that heavyweight concrete made with copper slag and magnetite can be used for production of turning wave block.

• Journal of the Korea Concrete Institute
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• v.25 no.4
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• pp.439-446
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• 2013

The objective of this study is to evaluate the workability and various mechanical properties of heavyweight magnetite concrete and examine the reliability of the design equations specified in code provisions. The main parameters investigated were the water-to-cement ratio and substitution level of normal-weight coarse aggregate (granite) for magnetite. The oven-dried unit weight of concrete tested ranged between 2446 and $3426kg/m^3$. The measured mechanical properties included compressive strength development, stress-strain curve, splitting tensile strength, moduli of elasticity and rupture, and bond stress-slip relationship of concrete. Test results revealed that the initial slump of heavyweight magnetite concrete increased as the substitution level of normal-weight coarse aggregate increases. The substitution level of normal-weight coarse aggregate had little influence on the compressive strength and tensile resistance capacity of heavyweight concrete, while it significantly affected the modulus of elasticity and stress-strain curves of such concrete. The design equations of ACI 349-06 and CEB-FIP provisions mostly conservatively predicted the mechanical properties of heavyweight magnetite concrete, but the empirical equations for modulus of elasticity and splitting tensile strength need to be modified considering the unit weight of concrete.

• Magazine of the Korea Concrete Institute
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• v.2 no.3
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• pp.81-88
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• 1990

For the protectioon of radioactive leakage, the quality control of main concrete structure in nuclear power plants is very important. So, this studey is designed to analyze the influence of kind of cement and aggregate on the mechanical properties of high density concrete. Test results of this study are as follows; 1)The slump of magnetite aggregate concrete(MAC) is found half value of nat.ural aggregate concrete (NAC). 2)As the effect of cement, the compressive strength of concrete using moderate heat cement is found higher 5-19 % than that of ordinary portland cement. 3)As the effect of fine aggregate, t.he compressive strength of MAC is found higher than that. of NAC below 340kg/$cm^2$ and lower t.han NAC above 340kg/$cm^2$. 4)As the effect of coarse aggregate, the compressive strength of MAC is found higher 17-22% than that of NAC.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.191-192
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• 2010

This study is a field application of high density concrete for a radiation shield at Korea Atomic Energy Research Institute. There are each process of investigation of using materials, producing arrangements, and field application products to satisfy presented specifications.

• 레미콘
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• no.1 s.86
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• pp.65-72
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• 2006

• Journal of the Korea Concrete Institute
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• v.28 no.4
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• pp.435-444
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• 2016

In Korea, approximately 48% of all households live in apartments, which are a form of multi-unit dwellings, and this figure increases up to 58%, when row houses and multiplex houses are included. As such, majority of the population reside in multi-unit dwellings where they are exposed to the problem of floor impact noise that can cause disputes and conflicts. Accordingly, this study was conducted to manufacture a high-weight, high-stiffness foamed concrete in order to develop a technology to reduce the floor impact noise. For the purpose of deriving the optimum mixing ratio for the foamed concrete that best reduces the floor impact noise, the amounts of the foaming agent, lightweight aggregate and binder were varied accordingly. Also, the target characteristics of the concrete to be developed included density of over $0.7t/m^3$, compressive strength of over $2.0N/mm^2$ and thermal conductivity of under 0.19 W/mK. The results of the experiment showed that the fluidity was very excellent at over 190 mm, regardless of the type and input amount of foaming agent and lightweight aggregate. The density and compressive strength measurements showed that the target density and compressive strength were satisfied in the specimen with 50% foam mixing ratio for foamed concrete and in all of the mixtures for the lightweight aggregate foamed concrete. In addition, the thermal conductivity measurements showed that the target thermal conductivity was satisfied in all of the foamed concrete specimens, except for VS50, in the 25% replacement ratio case for Type A aggregate, and all of the mixtures for Type B aggregate.