• Proceedings of the Korea Contents Association Conference
• /
• 2014.11a
• /
• pp.139-140
• /
• 2014

최근 건선산업에서 문제점으로 지적되고 있는 것은 제조과정 중 이산화탄소를 다량 방생시키는 시멘트의 사용이다. 이는 알칼리활성 무기결합재로 대체함으로써 시멘트보다 이산화탄소 배출량을 저감할 수 있지만 고가의 알칼리 자극제를 다량 사용하기 때문에 경제적 측면 및 사용성을 고려하지 않으면 사용할 수 없기 때문에 이에 대한 대체재에 관한 연구가 필요한 실정이다. 이에 본 연구에서는 고로슬래그를 기반으로 하는 알칼리 활성 무기결합재에 알칼리 자극제의 사용량을 저감하기 위해 레드머드를 사용하고, 레드머드에 적합한 알칼리 자극제의 종류와 사용방법에 대하여 연구하고자 하였다.

• Resources Recycling
• /
• v.19 no.4
• /
• pp.19-28
• /
• 2010

Attempts to increase the utilization of a by-products such as fly ash and blast furnace slag to partially replace the cement in concrete are gathering momentum. But most of by-products is currently dumped in landfills, thus creating a threat to the environment. Many researches on alkali-activated concrete that does not need the presence of cement as a binder have been carried out recently. However, most study deal only with alkali-activated blast furnace slag or fly ash, as for the combined use of the both, little information is reported. In this study, we investigated the influence of mixture ratio of fly ash/slag, type of alkaline activator and curing condition on the workability and compressive strength of mortar in oder to develop cementless alkali-activated concrete. In view of the results, we found out that the mixture ratio of fly ash/slag and the type of alkaline activator always results to be significant factors. But the influence of curing temperature in the strength development of mortar is lower than the contribution due to other factors. At the age of 28days, the mixture 50% fly ash and 50% slag activated with 1:1 the mass ratio of 9M NaOH and sodium silicate, develop compressive strength of about 65 MPa under $20^{\circ}C$ curing.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.5 no.4
• /
• pp.114-121
• /
• 2010

Portland cement production is under critical review due to high amount of CO2 gas released to the atmosphere. Attempts to increase the utilization of a by-products such as fly ash and ground granulated blast-furnace slag to partially replace the cement in concrete are gathering momentum. But most of by-products is currently dumped in landfills, thus creating a threat to the environment. Many researches on alkali-activated concrete that does not need the presence of cement as a binder have been carried out recently. However, most study deal only with alkali-activated ground granulated blast furnace slag or fly ash, as for the combined use of the both, little information is reported. In this study, we investigated the influence of mixture ratio of fly ash/ blast furnace slag tand curing condition on the flowability and compressive strength of mortar in oder to develop cementless alkali-activated concrete. In view of the results, we found out that the mixture ratio of fly ash/blast furnace slag always results to be significant factors. But the influence of curing temperature in the strength development of mortar is lower than the contribution due to other factors. At the age of 28days, the mixture 50% fly ash and 50% ground granulated blast furnace slag activated with 1:1 the mass ratio of 9M NaOH and sodium silicate, develop compressive strength of about 65 MPa under $20^{\circ}C$ curing.

• Resources Recycling
• /
• v.18 no.2
• /
• pp.39-50
• /
• 2009

Portland cement production is under critical review due to high amount of $CO_2$ gas released to the atmosphere. Attempts to increase the utilization of fly ash, a by-products from thermal power plant to partially replace the cement in concrete are gathering momentum. But most of fly ash is currently dumped in landfills, thus creating a threat to the environment. Many researches on alkali-activated concrete that does not need the presence of cement as a binder have been carried out recently. Instead, the source of material such as fly ash, that are rich in Silicon(Si) and Aluminium(Al), are activated by alkaline liquids to produce the binder. Hence concrete with no cement is effective in the reduction of $CO_2$ gas. In this study, we investigated the influence of the compressive strength of mortar on alkaline activator and curing condition in order to develop cementless fly ash based alkali-activated concrete. In view of the results, we found out that it was possible for us to make alkali-activated mortar with 70MPa at the age of 28days by using alkaline activator manufactured as 1:1 the mass ratio of 9M NaOH and sodium silicate and applying the atmospheric curing after high temperature at $60^{\circ}C$ for 48hours.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.613-616
• /
• 2008

Many researches on alkali-activated concrete that does not need the presence of cement as a binder have been carried out recently. Instead, the source of material such as fly ash and blast slag, that are rich in Silicon(Si) and Aluminium(Al), are activated by alkaline liquids to produce the binder. Hence concrete with no cement is effect reduction of CO$_2$ gas. In this study, we investigated the influence of the workability and compressive strength of mortar on water reducing agent, alkaline activator and curing method in oder to develop cementless blast slag based alkali-activated mortar. In view of the results, we found out that the flowability of mortar was lowered as increasing to mole concentration of NaOH, but not large the loss of flowability to 9M NaOH, most of water reducing agent was not effect. The compressive strength was improved as increasing to mole concentration of NaOH, was the most effect in 9M NaOH. The curing temperature and curing conditions on compressive strength of blast slag based alkali-activated mortar didn't influence.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.393-394
• /
• 2009

Recently, various researchers have studied alkali-activated concrete that do cementless as the binder. This study analyzed the effect on alkali-activated mortar by fineness of blast slag as the binder with no use of cement, by observing workability and compressive strength.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.6 no.1
• /
• pp.63-71
• /
• 2011

Portland cement production is under critical review due to high amount of $CO_2$ gas released to the atmosphere. Attempts to increase the utilization of a by-products such as fly ash and ground granulated blast-furnace slag to partially replace the cement in concrete are gathering momentum. But most of by-products is currently dumped in landfills, thus creating a threat to the environment. Many researches on alkali-activated concrete that does not need the presence of cement as a binder have been carried out recently. In this study, we investigated the influence of alkali activator and superplasticizer on the flowability and compressive strength of the alkali-activated mortar in oder to develop cementless alkali-activated concrete using blast furnace slag. In view of the results, we found out that the type and mixture ratio of alkali activator, the type and adding order of superplasticizer results to be significant factors. When cementless alkali-activated mortar using blast furnace slag manufactured with 1:1 the mass ratio of 9M NaOH and sodium silicate, and added superplasticizer before alkali activator in the mixer, we can be secured workability with 180 mm of flow during 1 hours and compressive strength of about 50 MPa under $20^{\circ}C$ curing condition at age of 28days.

• Journal of the Korean Wood Science and Technology
• /
• v.4 no.1
• /
• pp.21-27
• /
• 1976

This study was carried out in order to obtain the effect of active alkali concentration. Sulfidity 25%, maximum temperature 170$^{\circ}C$, cooking time 3hrs., liquor to wood ratio 5 : 1 in the kraft cooking conditions were maintained. Active alkali concentration were varied at intervals of 3% between 12% and 24%. The rates of de lignification increased with an increase in active alkali concentration and beatability, brightness, and strength of pulp also improved. The total pulp yield trand to decrease with an increase of active alkali concentration. The maximum screened pulp yield were obtained between 18% and 21% A.A.. Therefore, the optimum active alkali concentration was 18~21%.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2015.07a
• /
• pp.216-217
• /
• 2015

This study consist of research on the strength development properties of alkali activated slag(AAS) by differential combination of activators, initial protecting and curing conditions. 3 type of binders cured in the atmosphere, underwater and sealed were estimated compressive strength of 3, 7 and 28 days. Test results showed that strength development properties of binders varied with initial protecting and curing conditions because of ionized anions in pore water.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.3 no.3
• /
• pp.237-243
• /
• 2015

In this research, isothermal conduction calorimetry analysis has been conducted to investigate the reactivity of alkali activated slag binders. In order to secure the reactivity and workability of alkali activated slag binders, experiences with various types and concentrations of alkali activators were performed. Isothermal conduction calorimetry were measured with different alkali activators and mass ratio of $SO_3$ to binders as variables, and sodium tripolyphosphate ($Na_2P_3O_{10}$) and hydrated sodium borate ($Na_2B_4O_710H_2O$) were used to control setting time. As a results, alkali activated slag binders required alkali activators with 4 to 5 percent of concentration to accelerate the formation of calcium silicate hydrate(C-S-H) by alkali-activation, and overall heat generation rate delayed as accumulated heat decreased due to the high $SO_3$ contents. Moreover, the use of hydrated sodium borate as setting retarder causes elongated setting time due to delaying heat generation, so it can be considered that setting retarder played an important role in delaying total heat generation rate.