• Title/Summary/Keyword: 부순 잔골재

Search Result 43, Processing Time 0.027 seconds

A Study on the Evaluating Method the most Favorable Mixture Proportion of Blended Fine Aggregate for Effective Application of Recycled Aggregate (재생골재의 효율적인 활용을 위한 혼합잔골재의 최적배합평가방법에 관한 연구)

  • Han, Cheon-Goo;Yoon, Gi-Won;Lee, Gun-Cheol;Park, Yong-Kyu
    • Journal of the Korean Recycled Construction Resources Institute
    • /
    • v.2 no.1
    • /
    • pp.113-119
    • /
    • 2006
  • It is now established that more than two types of blended aggregate have beneficial effects on quality and supply of concrete in the long run. However, studies on blended aggregate have not widely been progressive and the evaluation method of its most favorable mixture proportion is still needed. Therefore this study investigated the most favorable mixture proportion through the physical experiment of fresh and hardened state's cement mortar, in response to three types of composite ratio, natural fine aggregate(Ns), crushed fine aggregate(Cs) and recycled fine aggregate(Rs). Test showed that increase of blending ratio of Ns and Cs improved fluidity of mot1ar. For the properties of compressive and flexural strength, mortar blending Ns and Cs properly, exhibited similar value to one using only Cs, while mortar mixing Rs showed lower strength value as less as 6% of control one. Mortar using only Rs exhibited the largest drying shrinkage value. In addition, even thought it is not a clear quantitative analysis, technical-imaging-skill presenting the most favorable mixture proportion 3-dimensionally is proposed in this research, in order to notify the proportion easily.

  • PDF

Influence of the Type of Fine Aggregate on Concrete Properties (잔골재 종류가 콘크리트의 물성에 미치는 영향)

  • Koh, Kyung-Taek;Ryu, Gum-Sung;Yoon, Gi-Won;Han, Cheon-Goo;Lee, Jang-Hwa
    • Journal of the Korea Concrete Institute
    • /
    • v.18 no.4 s.94
    • /
    • pp.459-467
    • /
    • 2006
  • Recently, interest grew on the quality of aggregates following the diminution of primary resources from river as to grow construction demand and the low grade of nature sand like sea sand. Following, need is to diversify the supply sources of fine aggregates which are excessively relying on sea sand and urgency is to find as soon as possible aggregate resources that can substitute sea sand. On the other hand, various fine aggregates are utilized to produce concrete in the domestic construction fields. However, few studies have been systematically investigated on the effects of such fine aggregates on concrete properties. Therefore, this study examined the effects of comparatively widely used fine aggregates in the domestic construction fields on the quality of concrete through the analysis of the effects of such fine aggregates on the physical properties of fresh concrete and strength of hardened concrete. Results revealed that crushed sand degraded the fluidity and air entraining of concrete compared to natural aggregates like sea sand and river sand. Especially, the use of crushed sand exhibiting bad grain shape and grade was larger adverse effect on the physical properties of concrete. The type of fine aggregates appeared to have negligible influence on the strength for W/C of 55%, 45% while crushed sand decreased the strength for W/C of 35% compared to natural aggregates. It analyzed that the combination of crushed sand exhibiting bad grain shape and grade with natural aggregates improved the characteristics of fresh concrete and had negligible influence on the strength.

The Influence of Fine Particles under 0.08 mm Contained in Aggregate on the Characteristics of Concrete (골재 중 0.08 mm 이하 미립분의 종류가 콘크리트의 특성에 미치는 영향)

  • Song, Jin-Woo;Choi, Jae-Jin
    • Journal of the Korea Concrete Institute
    • /
    • v.25 no.3
    • /
    • pp.347-354
    • /
    • 2013
  • Recently, crushed fine aggregates are being widely used due to the shortage of natural sand. In Korea, the amount of fine particles under 0.08 mm contained in crushed fine aggregates is restricted to be less than 7%, which is similar to the regulations of ASTM but is still very strict compared to the regulations of the other nations. In addition, the crushed aggregates already have in them about 20% of fine particles under 0.08 mm which occurs while they are crushed. The fine particles are not easy to wash out, and also to maximize the use of resources it is deemed necessary to review the possibility of enhancing the limit of the amount of fine particles. Therefore, this study conducted experiments to analyze the characteristics of fine particles under 0.08mm and their influence on the properties of concrete. Experiments using silt and cohesive soil were also done for comparison. In the experiments on fine particles, the methylene blue value was more in the soil dust contained in silt and cohesive soil than in the stone powder contained in crushed fine aggregates. Also, the methylene blue value had a close correlation with packing density and liquid & plastic limit. In the experiments done with concrete, the quantity of high range water reducing agent demanded to obtain the same slump increased as the fine particle substitution rate heightened. However, in the experiment which used stone powder testing the compressive strength and tensile strength of concrete in the same water-cement ratio, there was little change in strength with less than 20% addition of fine particles among the fine aggregates, and no meaningful difference in the amount of drying shrinkage of concrete.

Comparison of rheological properties containing natural and crushed sands in self-compacting concretes (잔골재 종류에 따른 고유동 콘크리트의 유동 특성)

  • Lee, Keun-Su;Choi, Yeol;Jung, Woong;Lee, Jae-Ik
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2008.11a
    • /
    • pp.365-368
    • /
    • 2008
  • In recent, the crushed sand as a fine aggregate has increasingly used for concrete industry due to the shortage of natural sand from river and the growing demand for protection of natural environments. Aggregates may have a significant influence on the properties of self-compacting concrete (SCC) including self-compacting mortar (SCM). The rheological properties of SCC and SCM using crushed sand as a fine aggregate has been compared to that of SCC and SCM using natural sand and mixed sand of both. Test results indicate that the yield stress of SCM containing 50% of mixed sand present higher than those prepared with natural sand and crushed sand according to SP content. the slump values of SCC with natural sand have approximately 5-15% higher than those of SCC with crushed sand. Also the L-box test values ($H_2/H_1$) of SCC with natural sand have approximately 20-30 higher than those of SCC with crushed sand under same water/cement ratio and viscosity enhancing admixture.

  • PDF

Effects of Crushed Fine Aggregate and Durability Improvement Agent (DIA) on Blast Furnace Slag-Based Brick (내구성증진용 혼화제(DIA) 및 부순 잔골재의 복합 치환이 순환잔골재를 사용한 고로슬래그 벽돌의 특성에 미치는 영향)

  • Park, Kyung-Taek;Son, Ho-Jung;Kim, Dae-Gun;Kim, Bok-Kue;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2011.11a
    • /
    • pp.225-227
    • /
    • 2011
  • This study investigates the effect of crushed fine aggregate and chemical admixture (durability improvement agent, named DIA) on blast furnace slag-based brick. The control brick was made with recycled fine aggregate of 100% and, no cement was used. Test results showed that all specimens developed similar strength, except for the specimen without partial replacement of crushed fine aggregate at 3 days. However, it is interesting to note that this specimen without crushed fine aggregate resulted in the highest strength at 7 days. In addition, the DIA had a major effect on the absorption ratio of brick specimens. For the brick specimens with partial replacement of crushed fine aggregate with 10%, the addition of DIA with only 1% was enough to satisfy the code regulated by KS F 4004.

  • PDF

Influence of Fine Aggregate Kinds on Fundamental Properties of Cement Mortar (잔골재 종류변화가 시멘트 모르터의 기초적 특성에 미치는 영향)

  • Kim, Seong-Hwan;Pei, Chang-Chun;Song, Seung-Heon;Cha, Cheon-Soo;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2006.05a
    • /
    • pp.85-88
    • /
    • 2006
  • This study investigated influence of fine aggregate types on fundamental properties of cement mortar. Test showed that concrete using lime stone crushed fine aggregate(L) exhibited the most favorable fluidity due to grain shape and particle distribution, and next was blending aggregate miting L and G, blending aggregate mixing L and N, granite crushed fine aggregate(G), natural fine aggregate(N) in an order. Concrete using N had the highest air content and L was the smallest value because of the effective filling performance by continuos particle distribution. Compressive, tensile and flexural strength of all concrete using L had the highest value due to the smallest value of air content. It is also found that concrete using L resulted in decrease of drying shrinkage length change ratio.

  • PDF

Influence of the Type of Fine Aggregate on Drying Shrinkage and Durability for Concrete (잔골재 종류가 콘크리트의 건조수축과 내구성에 미치는 영향)

  • Koh, Kyung-Taek;Ryu, Gum-Sung;Yoon, Gi-Won;Han, Cheon-Goo;Lee, Jang-Hwa
    • Journal of the Korea Concrete Institute
    • /
    • v.18 no.2 s.92
    • /
    • pp.249-255
    • /
    • 2006
  • Recently, interest grew on the quality of aggregates following the diminution of primary resources from river as to grow construction demand and the low grade of nature sand like sea sand. following, need is to diversify the supply sources of fine aggregates which are excessively relying on sea sand and urgency is to find as soon as possible aggregate resources that can substitute sea sand. On the other hand, various fine aggregates we utilized to produce concrete in the domestic construction fields. However, few studies have been systematically investigated on the effects of such fine aggregates on concrete properties. Therefore, this study examined the effects of comparatively widely used fine aggregates in the domestic construction fields on the shrinkage, durability and watertightness of concrete. Results revealed that drying shrinkage increases, and durability and watertightness degrades for concrete using crushed sand than natural fine aggregates like sea sand and river sand. Especially, the use of crushed sand exhibiting bad grain shape and grade was larger adverse effect on the quality of concrete. In addition, appropriate adjustment of the grain shape and grade during the blending of crushed sand exhibiting bad grain shape and grade with natural aggregates appeared to enhance the shrinkage and durability of concrete.

The Properties of Concrete Incorporating Stone Powders as Part of Fine Aggregates (잔골재의 일부로 사용된 부순골재 미분말이 콘크리트 성질에 미치는 영향)

  • Kang, Su-Tae;Seo, Jun-Young
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.20 no.5
    • /
    • pp.116-122
    • /
    • 2016
  • This study was intended to evaluate the properties of concrete incorporating stone powders which are created during crushing natural stones to produce crushed aggregates. For concretes with 0~30 wt.% partial replacement fine aggregates with stone powders, experiments of slump, air content, strength and drying shrinkage were carried out. The experiments found that the increase of the amount of stone powders sharply decreased slump and air content. Partially using stone powders instead of fine aggregates was found to increase both compressive and tensile strength slightly. Substituting higher amount of stone powders presented higher drying shrinkage. When HRWRA was added into the concrete with stone powders in order to obtain workability similar to that of plain concrete without stone powders for the same water-cement ratio and unit weight of cement, air content increased with the amount of HRWRA but strength and drying shrinkage were hardly affected by adding HRWRA.

Compressive Strength Evaluation of Concrete with Mixed Plastic Waste Aggregates Filled with Blast Furnace Slag Fine Powder (무기충진재를 혼입한 복합 폐플라스틱 골재를 활용한 콘크리트 압축강도 특성)

  • Lee, Jun;Kim, Kyung-Min;Cho, Young-Keun;Kim, Ho-Kyu;Kim, Young-Wook
    • Journal of the Korean Recycled Construction Resources Institute
    • /
    • v.9 no.3
    • /
    • pp.253-259
    • /
    • 2021
  • Plastic wastes generated from household waste are separated by mixed discharge with foreign substances, and recycling is relatively low. In this study, the effect of the ratio and content of mixed plastic waste coarse aggregate(MPWCA)s and mixed plastic waste fine aggregate(MPWFA)s filled with blast furnace slag fine powder on the slump and compressive strength of concrete was evaluated experimentally. The MPWCAs were found to have a similar fineness modulus, but have a single particle size distribution with a smaller particle size compared to coarse aggregates. However, the MPWFAs were found to have a single particle size distribution with a larger fineness modulus and particle size compared to fine aggregates. Meanwhile, the effect of improving the density and filling pores by the blast furnace slag fine power was found to be greater in the MPWFA compared to the MPWCA. As the amount of the mixed plastic waste aggregate(MPWA)s increased, the slump and compressive strength of concrete decreased. In particular, the lower the slump and compressive strength of concrete was found to decrease the greater the amount of MPWFA than MPWCA when the amount of MPWA was the same. This is because of the entrapped air and voids formed under the angular- and ROD-shaped aggregates among the MPWFAs. On the other hand, the addition of the admixture and the increase in the unit amount of cement were found to be effective in improving the compressive strength of the concrete with MPWAs.

The Experimental Study on the Properties on Concrete to use the Electric Arc Furnance Slag as Fine Aggregate (전기로슬래그 잔골재를 사용한 콘크리트의 기초물성에 관한 실험적 연구)

  • Choi, Sung-Woo;Kim, Jeong-Sik;Jeun, Jun-Young;Kim, Eun-Kyum;Ryu, Deuk-Hyun
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2008.11a
    • /
    • pp.389-392
    • /
    • 2008
  • Electric-furnace-slag has the expansion, due to the reaction with water and free Cao. So compared with the blast-furnace-slag, the recycling range of EFS is subject to restriction. But the expansive reaction of EFS is removed, the it is possible to use aggregate for concrete. This study is the basic properties of concrete to used stabilized EFS(oxidized EFS). The EFS is used fine aggregate in concrete, and replaced by sea-sand(natural sand). The replacement ratio are 0%, 25%, 50%, 75%, 100%. The result of study, to used oxidized EFS-sand, the flowability and the compressive strength is increased. Also it is possible to reduce the Bleeding. It is necessary more study about using the EFS aggregate, like the durability, the mechanical property for concrete

  • PDF