• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.543-544
• /
• 2009

The fiber(NY, PP) known to the effective material on improvement of the fire-resistance of HSC(high strength concrete) has a difference for fluidity according to the variation of a length and contents of fiber. In this study, to analyze the effect of a length and contents of the fiber on the fluidity of HSC and fheological characteristics, we calculated a viscosity of mortar by mini slump-flow, simple V-lot and viscometer. With the test results, the fluidity characteristic showed a moderate difference by a length and contents of the fiber, but showed a significant difference by increase of the fiber contents. ${\ast}$ AFR Concrete (Advenced Fire Resistant Concrete)

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2014.05a
• /
• pp.132-133
• /
• 2014

In this study, high volume of industrial by-products including blast furnace slag, recycled aggregate powder and incineration ash have been utilized on the slurry of the foamed lightweight concrete. As to decrease the price of the lightweight foam concrete, mortar based slurry and concrete based slurry has been fixed. As the variation of the foam conduction ratio and aggregates, the foam ratio and compressive strength has been tested. Results showed that using recycled aggregates in the slurry showed better effect than using natural aggregates due to the alkali properties of the recycled aggregates could activate the potential hydraulic properties of the blast furnace slag. Consider about the low price of the recycled aggregates, it could be identified that using recycled aggregates in high volume blast furnace slag blended lightweight concrete showed better compressive strength than natural aggregates.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1995.10a
• /
• pp.69-74
• /
• 1995

The primary purpose of this study is to investigate reusal techniques of fly ash of combined heat power plant in the construction field, which may contribute to the saving of construction materials and conservating environment. Firstly chemical and physical characteristics of fly ash is analysed. And then, the usability of the concrete is tested by investigating the flowablility and stength development through parameters of various replacement ratios with respect to different mixing conditions. Finally, the durability and mechanical properties(elastic modulus) of the concrete is tested. As the result of the study, the following conclusions are derived : (1) the quantity of the CaO in the fly ash is relatively high based on the chemical analysis, (2)the compressive strength ratio of the mortar is satisfied with the specification, but the unit water ratio increased, (3)high strength concrete of more than 400kg/$\textrm{cm}^2$ can be developed in the ranges of FA 30%, W/B 40%, (5)the slump loss with the elapsed time due to the delivery is decreased as the replacement ratio of the fly ash is increased, (6)the modulus of the elasticity is matched withn the specification of the Architectural Institute of Korea.

• Journal of the Korea Institute of Building Construction
• /
• v.1 no.2
• /
• pp.146-153
• /
• 2001

Radical development has been made in the every field of our society for the past scores of year. Radical development of industry and lining environment has mass-produced various toxic wastes . Which comes to the fore as a serious environmental problem. The purpose of this is to suggest the optima mix design by studying the utility of a toxic waste, plated sludge as a building material and deciding the standards of quality and use of cement and evaluating the properties of mortar and concrete in which plated sludge mixed. From an experiment, compressive strength required high early strength cement or special cement. Watertightness proved to be excellent. Heavy metals, such as Cd, Pb, Cu came out below an environmental standard. Cr+6 exceeded an environmental standard under a steam curing, but came out below an environmental under a standard curing. The higher replacement rate was, the lower frost, fusion and resistance were. Thus, got better results above the goal by condition. It was possible that plated sludge was replaced and solidified to aggregate. Therefore, it is necessary to define the standards of quality on strength, replacement rate of wastes, water permeability, endurance in other to solidify plated sludge to concrete products.

• Journal of the Korean Ceramic Society
• /
• v.55 no.3
• /
• pp.224-229
• /
• 2018

OPC production requires high calorific value and emits a large amount of $CO_2$ through decarbonation of limestone, accounting for about 7% of $CO_2$ emissions. To reduce $CO_2$ emissions during the Ordinary Portland Cement (OPC) production process, there is a method of reducing the consumption of cement or lower temperature calcination for OPC product. In this study, for energy consumption reduction, we prepared Hauyne-belite cement by calcination at a low temperature compared to that used for OPC and studied the early hydration properties of the synthesized Hauyne-belite cement. We set the ratios of Hauyne and belite to 8 : 2, 5 : 5 and 3 : 7. For the hydration properties of the synthesized Hauyne-belite cement, we tested heat of hydration of paste and the compressive strength of mortar, using XRD and SEM for analysis of hydrates. As for our results, the temperature for optimum synthesis of Hauyne-belite is $1,250^{\circ}C$. Compressive strength of synthesized Hauyne-belite cement is lower than that of OPC, but it is confirmed that compressive strength of synthesized Hauyne-belite cement with mixing in of some other materials can be similar to that of OPC.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.655-658
• /
• 2001

The generation of fly ash tends to increase yearly so that this is currently considered a big environmental concern, which requires appropriate treatment approaches. In this research the consolidation of incineration fly ash by the hot-press solvothermal reaction was investigated to provide an alternative process for the treatment and utilization of this waste material. Results showed that at reaction conditions of 52 K treatment, 20 ㎫ pressure and 60 minutes treatment time, the resulting consolidate exhibited a compressive ness strengths of 37-40 ㎫, a tensile strength of 6.5-7.0 ㎫ and a Rockwell hardness of 20-23 RH15W. These properties are comparable to the compressive ness strength of Portland cement which ranges from 30-40 ㎫ as well as with the tensile strengths of mortar, ganite, artificial lightweight aggregate and solidified high connote whose values are 2-2.5 ㎫, 5-9 ㎫, 5-10 ㎫ and 3-5 ㎫ respectively- Furthermore, by mixing fly ash with glass at 50% ratio and then subjecting to similar treatment conditions, a consolidate with even higher tensile strength of 12.5-13.3 ㎫ and hardness of 77-80 RH15W may be achieved.

• Journal of the Architectural Institute of Korea Structure & Construction
• /
• v.33 no.12
• /
• pp.63-70
• /
• 2017

When industrial by-products like slag and fly ash are using in concrete with cement, it improves strength and durability against external deterioration factors by densifying the structure through potential hydraulic and pozzolanic reaction. But it has been pointed out that high dependence on the quality variation and the curing condition using a admixure material for concrete. In this study, the characteristics of internal micropore structure according to curing condition were analyzed for pastes and mortar specimens under using blast furnace slag powder. As a result, the variation of compressive strength and the internal microstructure were observed according to curing conditions by binder type. Particularly, using blast furnace slag powder, decrease in compressive strength were clearly observed in indoor and carbonation curing compared with water curing. The pore structure analysis also clearly observed the decrease of the gel pore existing in the CSH hydrate layer and the increase of the capillary pore in indoor and carbonation curing compared with water curing condition.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2015.11a
• /
• pp.45-46
• /
• 2015

Recently, the large amount of sulfur is globally generated by the development of the petroleum refining industry every year. In this study, without the use of the sulfur with a high melting point used in the previous studies, the modified sulfur mortar with addition of a melting point of about 65℃ were tested to determine their distribution and strength properties according to the mixing method and curing conditions. This study is a test to find out the Density, Absorption and Table Flow of the modified sulfur and general sulfur. As result, general industrial sulfur flow was lower, showed a high absorption rate.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1999.10a
• /
• pp.791-794
• /
• 1999

Exact estimation of cement content in a hardened concrete can provide useful data to evaluate the quality and strength of the concrete and might be used to inspect the quality of precast concrete secondary products. Observation obtained in this research included : (1) the volume of coarse aggregate in the hardened concrete measured by the area comparison method has a high accuracy ; (2) the cement content in the mortar and the X-ray intensity of Ca-K$\alpha$ have a correlation factor of 0.96 ; (3) the cement content in the ready mixed concrete was estimated with high accuracy such as correlation factor of 0.99 and standard deviation of 0.64.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05a
• /
• pp.66-69
• /
• 2006

Three reinforced concrete rigid frames and infilled rigid frames with new retrofitting system were tested under both vertical and cyclic loadings, Experimental programs were carried out to evaluate and improve the seismic performance of such test specimens, such as the hysteretic behavior, the maximum horizontal strength, crack propagation, and ductility etc. under load reversals. All the specimens were modeled in one-third scale size. For specimens(RFHPC, RFAR) designed by the improving of seismic performance of the rigid frame using the high ductile fiber composite PC panel and ALC panel system, load-carrying capacities were increased $1.45{\sim}2.28$ times, and hysteretic behavior was very stable during the final tests in comparison with the standard specimen(SRF).