자연 및 인위적 처리방법 변화에 따른 순환잔골재의 pH저감

한천구,한민철,한상윤,Han, Cheon-Goo,Han, Min-Cheol,Han, Sang-Yoon 한국건설순환자원학회 2011 한국건설순환자원학회지 Vol.6 No.1

This study is to comparatively analyze the characteristics of pH decrease in recycled fine aggregates for embankment and landfill produced from waste concrete by using natural process and artificial process. The result was as follows In case of recycled fine aggregates left outdoor, it was found that pH level was decreased if the thickness of embankment becomes thinner, or the materials left outdoors owing to high concentration of $CO_2$ in atmosphere caused by respirations of people. When the air was permeated, pH level was decreased more effectively. It was analyzed that this phenomenon was caused by efficient supply of $CO_2$ in the recycled fine aggregates owing to high-pressure ventilators. In case of water spraying treatment, sprayed water facilitated hydration of unhydrated cement to dissolve calcium hydroxides which neutralized $CO_2$ in the atmosphere during desiccation process and decrease pH level by a considerable margin. In case of Immersed treatment, decrease of pH was not sufficient. When facilitating the supply of $CO_2$, pH level of the recycled fine aggregates was decreased by the largest margin. It was analyzed that this phenomenon was caused by efficient supply of $CO_2$. From the above results, it was analyzed that the most effective method of reducing pH level of the recycled fine aggregates from the aspects of pH reduction performance, economic efficiency and workability was repeated wet-dry cycles of spraying water to the aggregates in the proportion of 1:0.5 by weight and then treating by forcefully blowing $CO_2$ gas into the aggregates.

고로슬래그 미분말과 순환잔골재를 사용하는 무 시멘트 모르타르의 특성에 미치는 순환골재 미분말의 영향

한천구,손석헌,박경택,Han, Cheon-Goo,Son, Seok-Heon,Park, Kyung-Taek 대한건축학회 2011 대한건축학회논문집 Vol.27 No.6

This study is to investigate experimentally the effect of the use of recycled aggregate powder(RP) on the properties of mortar using recycled fine aggregates(RA) and blast furnace slag powder(BS) without portland cement. The results can be summarized as follows : For the fresh mortar, an increase in RP contents leads to increase W/B, Air contents increase gradually below 100 % of RP contents. As the RP contents increase, the compressive strength decrease gradually. Besides, as the RP contents increase, the strength deviation with curing temperature is negligible at 91 days, compressive strength at $20^{\circ}C$ was higher than that at $35^{\circ}C$. The flexural strength show a similar trend to the compressive strength in general, and the ratio of compressive strength to flexural strength is distributed within 1/1 ~ 1/3 in general, which is higher than the range of ordinary concrete. Meanwhile, as a result estimation of strength development, as the RP contents increase, the strength development trend is weakened gradually, but elapse with age, in case of RP 25 % show that strength level has similar with BS 100 %. It is thought that substition of RP for BS will be available for securing quality improvement within 25 %.

순환잔골재를 사용한 무 시멘트 고로슬래그 모르터의 배합요인에 따른 품질특성

한천구,손석헌,박경택,Han, Cheon-Goo,Son, Seok-Heon,Park, Kyung-Taek 한국건설순환자원학회 2010 한국건설순환자원학회지 Vol.5 No.3

This study is to investigate experimentally the influence of mixing factors, such as a mortar mix proportion of non-cement mortar, flow, and W/B, on quality characteristics of blast furnace slag powder mortar incorporating dry type recycled fine aggregates. In the characteristics of fresh mortar, the W/B increased according to the increase in the flow due to the increase in water contents, but air contents decreased due to loss of air contrary to the increase in the W/B. In the case of hardened mortar, the compressive strength showed a decrease due to the highly determined W/B inversely according to the increase in the flow through the entire age in which the compressive strength increased proportionally according to the increase in the B/W. Also, the increasing rate of such compressive strength increased more largely due to the latent hydraulic property of the BS according to the passage of the age. The flexural strength at the age of 28 days according to the increase in the B/W represented a similar level in strength values without any increases. The flexural strength for the compressive strength was distributed as a range of 1/2 ~ 1/3 and that showed a higher range than that of conventional concretes.

폐유지류를 중심으로 한 도포제 종류 및 도포시기 변화가 혼화재 다량치환 콘크리트의 탄산화 및 염해저항성에 미치는 영향

한천구,최영두,Han, Cheon-Goo,Choi, Young-Doo 한국건설순환자원학회 2015 한국건설순환자원학회 논문집 Vol.3 No.3

본 연구는 폐유지류를 중심으로 한 도포제 종류 및 도포시기에 따른 혼화재 다량치환 콘크리트의 탄산화 및 염해저항성에 미치는 영향에 관하여 실험 연구한 것이다. 즉 내구성 향상방안으로서, 도포시기를 탈형 즉시와 28일 수중양생후의 변화를 주고 도포제는 Plain인 Control을 포함한 ERCO(유화처리정제유지류), RCO(정제유지류), WR(발수제), ERCO+WR의 5가지 수준에 대하여 비교 실험을 실시하였다. 실험결과 도포시기에 따른 탄산화 및 내염해 저항성의 경우 28일 수중양생 후 도포의 경우 탄산화 및 염화물 침투 깊이가 감소하는 것을 알 수 있었고, 또한, 도포제는 ERCO, RCO, ERCO+WR, WR의 순으로 탄산화 및 염화물 침투깊이가 늦게 진행되어, 특히 ERCO의 도포가 탄산화 및 염화물 억제효과에 가장 우수한 것을 알 수 있었다. In this research, the influence of painting materials and applying timing on carbonation and chloride resistances of high volume SCMs concrete was evaluated. As a durability improving method, comparative tests were conducted with painting materials of ERCO (emulsified refined cooking oil), RCO (refined cooking oil), WR (water repellent agent), and ERCO + WR and with painting timings of right after demolding, and 28 days after the wet curing. From the experiment results, in the case of carbonation and chloride resistance, the carbonation depth and chloride penetration depth were decreased when the painting materials were applied in 28 days of wet curing. Additionally, for painting materials, with the order of ERCO, RCO, ERCO+WR, and WR, the carbonation and chloride penentration was delayed. Hence it is considered that ERCO shows the most favorable performance of resistance against carbonation and chloride penetration.

순환잔골재와 플라이애시를 사용하는 모르터의 배합요인 변화에 따른 품질특성

한천구,손석헌,박경택,Han, Cheon-Goo,Son, Seok-Heon,Park, Kyung-Taek 한국건설순환자원학회 2010 한국건설순환자원학회지 Vol.5 No.4

This study analyzed the effects of changes in mixing factors of zero-cement mortar that only used recycled fine aggregates and fly-ash on quality of mortar, and the results are as follows. To describe the property of fresh mortar, as mix proportion and flow of mortar increased, W/B was highly selected and air content decreased. To describe compressive strength according to age as the property of hardened mortar, it was revealed that the strength did not strength until the 14 day, but strength of about 1 ~ 2 MPa strength during the 14 day through 28 day, and almost similar strength after 28 day. Also, compressive strength according to changes in mix proportion, flow and B/W was generally similar. Summarizing the above experimental results, in case of mortar that used recycled fine aggregates and fly-ash, it secured the strength for the use of landfill even though not for structural use. Especially, poor mix proved to be more useful than rich mix.

품질향상재 종류 및 치환율 변화에 따른 순환잔골재 사용 고로슬래그 모르타르의 품질향상

한천구,김대건,Han, Cheon-Goo,Kim, Dae-Gun 한국건설순환자원학회 2012 한국건설순환자원학회지 Vol.7 No.1

In this study, the research examined the effect on FC, WG, RP replacement ratio on the quality improvement of BS mortar using the RA. First of all, the flow value increased as the FC contents increased, and decreased as the WG and RP contents increased. The air contents was reduced as the FC and RP contents increased, but was increased as the WG contents went up While the compressive strength of 1 : 7 mix proportion increased with the increase of the FC and WG contents, it decreased as there was more RP contents. The compressive strength of RP could increase as the mix proportion increased, but the difference depending on the improvement material type and replacement ratio decreased gradually. The absorption deteriorated as the FC and RP contents increased in all the mix proportions, but improved a little when WG was used. Meanwhile, the absorption decreased as the compressive strength improved in all the mix proportions as a correlation, but the order was FC, RP and WG depending on the quality improvement material types. The FC and WG were most favorable in terms of quality improvement as a total analysis, and the RP and WG was most effective in terms of economical efficiency and resource recycling.

광물질 혼화재 사용 초고강도 모르타르 및 콘크리트에 CASB 화합 고성능감수제의 효과분석

한천구,유승엽,Han, Cheon-Goo,Yoo, Seung-Yeup 한국건설순환자원학회 2011 한국건설순환자원학회지 Vol.6 No.1

This study is performed to analyze the effects of CASB by applying the superplasticizer combined CASB on the ultra high strength mortar and concrete that uses different mineral admixture depending on whether the silica fume was used and the results are summarized below. From the characteristics of Fresh mortar and concrete, the fluidity was lower in B2-CASB than B2-PC from the mixing of CASB and based on the viscosity of the mortar and concrete in the binary proportion but in the ternary proportion, B3-CASB showed a larger fluidity than B3-PC because of a reduction in the restriction level due to the effects of an improvement of particle size distribution. The compression strength was higher in ternary proportion than in binary proportion and higher in CASB than in PC from the characteristics of hardening mortar and concrete and this is analyzed as a result of increased minuteness from the calcium silicate hydrates produced from the pozzolan reaction of a mineral admixture, SF, and also the charging effects of capillary pore of CASB. Overall, when using the nanomaterial, CASB in combination with a superplasticizer, the fluidity and the strength aspects of the ternary proportion of ultra high strength mortar and concrete with silica fume may be improved to a higher quality.

콘크리트의 기온보정강도 적용에 관한 자료분석 연구

한천구,한민철,Han, Cheon-Gu,Han, Min-Cheol 한국레미콘공업협회 1997 레미콘 Vol.1 No.-

고 분말도 고로슬래그미분말 혼합재(HBS)를 활용한 고성능콘크리트의 내구성 평가

한천구,김종백,Han, Cheon-Goo,Kim, Jong-Baek 대한건축학회 2011 대한건축학회논문집 Vol.27 No.11

This paper is investigate the effect of high blaine blast furnace slag powder(HBS) on the durability of high performance concrete. The use of HBS requires an increase in dosages of superplasticizer by as much as 0.1~0.2 % and makes the concrete satisfied the target slump flow and air contents. An increase in HBS resulted in an increase of compressive strength due to latent hydraulic reaction. Coefficient of chloride diffusion, sulfate resistance and freeze thaw test results showed improved performance when HBS was incorporated. the use of HBS decreased peak temperature based on semi adiabatic temperature test. hence, it is confirmed that the addition of HBS improved strength and durability.

화재시 고성능 콘크리트의 폭열에 미치는 골재종류 및 폴리프로필렌 섬유의 영향

한천구,양성환,이병렬,황인성,Han, Cheon-Gu,Yang, Seong-Hwan,Lee, Byeong-Ryeol,Hwang, In-Seong 한국레미콘공업협회 2000 레미콘 Vol.1 No.-