• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.9 no.3
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• pp.161-169
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• 1980

In order to enhance the thermal energy storage capacity of cement mortar and to improve the effective thermal conductivity of paraffin waxes, cement- sand- paraffin wax mixture was investigated. By means of finite difference method, the transient temperature distribution in a hollow cylinder with phase change using average composite properties was obtained, and compared with experimental results. It was shown that the heat absorbed by mixture with $25\%$ paraffin fraction was as much as $50\%$ more than either a concrete mortar or pure paraffin wax in the case of ${\Delta}T=\;18.25^{\circ}C$.

• Environmental Engineering Research
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• v.21 no.3
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• pp.241-246
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• 2016

This paper discusses the influence of organic matter contained in aggregate on the emission characteristic of ammonia ($NH_3$) from cement mortar. $NH_3$ can be released to indoor-outdoor environment through diffusion in mortar (or concrete) and have resulted in the increasing air pollution, and especially well known as a harmful gas for the human body. The concentration of $NH_3$ released from cement concrete was then compared to the contents of organic matter contained in the aggregate. The result indicates that the contents of organic matter in the aggregate significantly differ with types of aggregate from different areas of production. The organic matter becomes organic nitrogen through the process of microbial breakdown for a certain period and pure ammonium ion ($NH_4{^+}$) is produced from the organic nitrogen. The $NH_4{^+}$ was reacted with alkaline elements in the cement and released as $NH_3$ from cement concrete through a volatile process. The released $NH_3$ was proportional to the contents of $NH_4{^+}$ adsorbed in the aggregate from different areas of production and the concentrations of $NH_3$ emission from cement mortar according to the aggregate differ by more than 4 times.

• Advances in concrete construction
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• v.6 no.6
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• pp.611-629
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• 2018

The objective of present study is to investigate the effect of granulated blast furnace slag (GBS) as partial substitution of natural sand on behaviour of cement mortar. For this, the methods of factorial design with water cement (w/c) ratio and incorporation percentages of GBS as replacement of natural fine aggregate i.e., GBS(%) as factors are followed. The levels of factor w/c ratio are fixed at 0.4, 0.45, and 0.5 and the levels of factor GBS(%) are kept fixed as 0%, 20%, 40%, 60%, 80% and 100%. The compressive strength (CS) of mortar after 3, 7, 14, 28, 56 and 90 days, and water absorption (WA) are chosen as responses of the study. Analysis of variance (ANOVA) of experimental results has been carried out and those are illustrated by ANOVA tables, main effect and interaction plots. The results of study depict that the selected factors have substantial influence on the strength and WA of mortar. However, the interaction of factors has no substantial impact on CS and WA of mixes.

• Journal of the Korea Institute of Building Construction
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• v.23 no.4
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• pp.359-367
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• 2023

This experimental study investigates the replacement of conventional Portland cement and sand with non-sintered cement and ferro-nickel slag to formulate eco-friendly cement mortar. The examination aimed to understand the strength properties of non-sintered cement mortar using ferro-nickel slag as fine aggregate by classifying mortar production types, fine aggregates, and curing methodologies. From flexural and compressive strength tests, it was observed that non-sintered cement mortars, incorporating ferro-nickel slag as fine aggregate, exhibited superior strength when compared to both plain mortar and steam-cured non-sintered mortar. This increased strength is attributed to the influence of the particle size, density, and absorption capabilities of the ferro-nickel slag. Furthermore, X-ray Diffraction(XRD) analyses of the mortars verified the presence of MgO, a component of ferro-nickel slag, in the form of a composite oxide. This finding substantiates the consistent strength manifestation of non-sintered cement mortars utilizing ferro-nickel slag as a fine aggregate.

• Journal of the Korea Institute of Building Construction
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• v.19 no.2
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• pp.105-112
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• 2019

Fine aggregate made of ferronickel slag(FNS) is similar to natural fine aggregates and is used in concrete structures both domestically and abroad, but its applications and research areas are limited. In this research, in order to expand the availability of FNS and improve the performance of cement mortar products, the applicability of FNS on dry mortar for floor was examined. Experimental results show that FNS improves flow of cement mortar because it has low absorption rate, spherical shape, and glassy surface. Also, the high stiffness of the FNS aggregate itself is considered to contribute to the improvement of cement mortar quality such as crack reduction by improving the compressive strength and shrinkage reducing. In addition, when FNS fine aggregate is applied, it was possible to secure the impact sound insulation performance equal to or higher than that of mortar using natural fine aggregate.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.93-102
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• 1995

In this study the characteristics of adiabatic and lightweight of cement mortar was improved by using porous Bottom ash which was industrial waste. when a foaming agent was added, the characteristics of mortar using sand and Bottom ash were compared. From the empirical results the heat-transfer ratio for the mortar using Bottom ash only was shown the lower values than that for a general mortar, and the lightweight concrete with unit weight of 1.5t/$\textrm{m}^3$ could be made. When the foaming agent of 0.25% and 0.5% in usage of cement was added to that, the compressive strength scould be measured as 5 and 8times of the general mortar respectively. Also, the characteristics of adiabatic for that mortar was great improved so that the heat-transfer ratio was fallen to 0.172kcal/$mh^{\circ}C$.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.1
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• pp.55-62
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• 2003

This study has investigated physical and chemical properties of FRP waste, has manufactured polymer cement mortar using a crushed waste with sand and has evaluated its capability to develop the economical waste recycling technology. The study has investigated tension strength, hardness test and impact test as physical properties and also thermogravimetric characteristics and analyzed infrared spectroscope as chemical properties. Then the study has manufactured polymer cement mortar and has analyzed how the FRP waste fine aggregate replacement ratio has an effect on compression strength. Noticing admixture can complement strength drop occurred by the FRP waste fine aggregate replacement, the study examined an optimum rate of admixture addition and its reaction through electron microscope photos.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.138-143
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• 1993

The objective of this report is to investigate the effect of factors like the fineness modulus of sand , content of fly ash and slaked lime, binder/sand ratio, admixture dosage on the physical properties of mortar for finishing. The analysis was performed with design of experiment and air content, water retention and compressive strength were measured.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.186-187
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• 2022

The purpose of this study was to give fluidizing properties to non-sirtered cement made using by-products that can replace Portland cement by using a fluidizing agent. Blast furnace slag, C-type fly ash, and F-type fly ash were used for non-sirtered cement, and sand was used for aggregate. The amount of fluidizing agent used was fixed at 1%, and the water-cement ratio (W/C) was different by setting the binder blending ratio of the non-sintered cement differently, and the fluidity test and flow were compared. As a result of the experiment, when the flow standard was 170mm when the fluidizing agent was used, the fluidizing properties were shown at an average water-cement ratio (W/C) of 36%. Through this study, it was confirmed that the fluidizing properties appeared when the fluidizing agent was used in non-sintered cement.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.322-325
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• 2003

Recently, as quality river aggregates like sands and gravels become scarce, use of crushed stones and sands, seashore sands, and seashore gravels is increasing abruptly. And, aggregates recycled from slags and waste concretes are used. However, since the converter slag easily expands and breaks due to free lime, differently from the blast-furnace slag, it is not suitable for use as concrete aggregates. Since the atomized steel slag aggregate has slippery surface and spherical shape, the mortar flowing characteristics improved as the atomized steel slag content increases, without regard to the aggregates coarseness and water/cement ratio. The flow characteristics loss rate of the mortar manufactured from steel slag aggregates was similar to that of the mortar manufactured from washed sand only. The compact strength of the mortar manufactured from coarse PS Ball were larger than that manufactured from washing sand only.