• Journal of the Korean Recycled Construction Resources Institute
• /
• v.4 no.4
• /
• pp.439-445
• /
• 2016

Recently, a large number of researches about concrete containing high volume fly-ash(HVFA) have been carried to obtain carbon dioxide reduction, resource recycle and durable option in concrete industry. The quality of fly-ash such as chemical composition and fineness has high variability due to the differences of used fuels, operation condition in power plant. The aim of this study is to investigate the performances of fly-ash cement mortar containing different type of fly-ashes. The basic analysis of fly ash such as chemical composition, SEM image analysis were performed. Many mortar specimens were fabricated to evaluate the properties (compressive strength, drying shrinkage and carbonation) of mortar with various fly ash. From the test results, the quality of each fly ash must be considered and fully weighted in fly ash concrete.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.271-272
• /
• 2009

In this study, the application results of high volume fly ash concrete(HVFAC) on the construction site were reported. The structures were the mat foundations of 3m and 2m thickness with design strength of 40MPa. The replacement ratio of fly ash was 50%, and the pre-mix type binder was used. As a result, it appeared that the temperature increases of concrete foundations were about $39^{\circ}$C for 3m thickness and $36^{\circ}$C for 2m thickness.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2010.05a
• /
• pp.309-310
• /
• 2010

In this study we investigated the properties of the fundamental and adiabatic temperature rise of the concrete using high volume fly-ash. For this, the fly ash was used to replace cement at replacement ratio of 40% and 50% by mass, and then the slump, air content, bleeding, compressive strength and adiabatic temperature rise test of concrete were performed.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.10a
• /
• pp.281-286
• /
• 2002

To study of binder and fine aggregate a lot of replacement fly-ash concrete, initial characteristics, standard environment of curing temperature $20^{\circ}C$, hot-weather environment of curing temperature $35^{\circ}C$, . Flesh concrete tested slump. air contest and Hardening concrete valuated setting period of form, day of age 1, 3, 5. 7, 10, 28 compression strength in sealing curing. Purpose of study is consultation materials in field that variety of fly-ash replacement concrete mix proportion comparison and valuation. (1) Experiment result age 28day compression strength more higher plan concrete then standard environment in curing temperature $20^{\circ}C$, , most strength F43 is hot-weather environment in curing temperature $35^{\circ}C$, replacement binder 25%, fine aggregate 15%. (2) Hot-weather environment replacement a mount of fly-ash is a same of plan concrete setting period of form. Age 28day compression strength replacement a mount of fly-ash more hot-weather concrete then plan concrete.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.2 no.3
• /
• pp.202-208
• /
• 2014

For evaluating basic structural behavior of HVFA (High Volume Fly Ash) concrete, several tests are performed considering different ratios of fly ash replacement and structural evaluation regarding compressive strength, elasticity modulus, stress-strain relationship, and bond strength is also performed. Test results show that elasticity modulus of HVFA concrete has close relationships with compressive strength and fly ash replacement ratio. The ultimate strain shows slight difference from domestic design code. On the other hand, there are no differences between general concrete and HVFA concrete for elasticity modulus and bond strength.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.417-420
• /
• 2008

In this study, the characteristics of strength development and hydration heat on high volume fly ash concrete(HVFAC) was experimentally investigated. Two levels of W/B were selected. Seven levels of fly ash replacement ratios and two levels of silica fume replacement ratios were adopted. In the concrete mix, the water content of $125kg/m^3$ was used, which is less than that of usual water content. As a result, it appeared that the compressive strength gradually decreased with increasing fly ash replacement ratio at the early age, but the difference of strength up to replacement ratio of 50% was little at the age of 91 days because of the pozzolanic reaction of fly ash. The effect of hydration heat reduction on the concrete was affected by the fly ash replacement ratio. When the replacement ratio was over 30%, the reduction efficiency of hydration heat was large.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2002.11a
• /
• pp.63-66
• /
• 2002

In this study, it does a high volume flyash substituted concrete experiments in two curing temperature circumstances - 35$^{\circ}C$, 2$0^{\circ}C$. High volume flyash concrete is tested in fresh concrete properties and hardeded concrete properties. In the fresh concrete test items, there is slump, air contents, concrete setting tests. 3, 7, and 28 days water curing compressive strength is measured in the hardened concrete test. The purpose of this study is to submit a various flyash concrete data for application to field. The result of this study is that the best strength is developed at the plain concrete cured 2$0^{\circ}C$ and Mixing F43 shows the best strength among specimens which cured at 35$^{\circ}C$

• Journal of the Korea Institute of Building Construction
• /
• v.10 no.1
• /
• pp.39-47
• /
• 2010

Fly ash has the advantages, among others, of improving the characteristics of concrete, reducing the price of concrete products, improving the durability, and reducing hydration heat. However, when added in mass, it leads to problems such as insufficient concrete intensity, increase of AE use, and others, resulting in a limitation of the use volume. Therefore, this study is undertaken to solve the problems associated with themass use of fly ash through the high concentration powder ($4000{\sim}8000cm^2/g$) of fly ash, curing method, the addition of an alkali stimulation agent and others for the purpose of increasing the added value of the fly ash. The research showed that the intensity manifestation has an outstanding status, with the hydrates reaching a very stable condition if the rate of addition of a stimulation agent is appropriately used with the heightening of the fineness of the fly ash in the temperature range of $40^{\circ}C$, and if the applicable study is continued, it is likely to result ineffective value generation on the massive replacement of fly ash.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.10a
• /
• pp.269-274
• /
• 1998

In this study, to increase fluidity and resistance of segregation of materials, the effect of each of the materials, which have effects on high performance concrete from investigating the properties of strength and drying shrinkage of high performance concrete made by the basic mix proportion used fly-ash and ground granulated blast-furnace slag after hardening, has been checked. According to the experimental results, fluidity on W/C = 34% was satisfied within slump-flow 65$\pm$ 5cm and U-type self-compactability difference 5cm. On the properties of strength, high performance concrete produced compressive strength over 400kg/$\textrm{cm}^2$ in 28days when powder was replaced by 40% of fly-ash and 60% of ground granulated blast-furnace slag. And compressive strength was taken over 600kg/$\textrm{cm}^2$ equal to non-replacement in 91days. Also, the length change of concrete with the addition of fly-ash was smaller than that without it. Therefore, it may be effective on the decrease of drying shrinkage volume.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2019.05a
• /
• pp.112-113
• /
• 2019

Recently, supplementary cementitious materials such as blast-furnace slag, fly ash and silica fume have been widely used as substitutes for cementitious materials. In this study, the deformation behavior of compressive loading of C₃S paste with 50% fly ash was analyzed by X-ray scattering data and pair distribution function analysis. The obtained results were compared with 131-day-old pure C₃S paste. The Ca(OH)₂ of the C₃S-FA paste showed almost complete elastic behavior, consistent with the deformation behavior of the r-range of 20 to 40, and the C-S-H phase contributed to the range of PDF r-range of less than 20. In addition, C-S-H of C₃S-FA showed greater deformation resistance than C₃S paste.