• Title/Summary/Keyword: Unit cement content

Search Result 159, Processing Time 0.031 seconds

An Experimental Study on the Mixing and Mechanical Properties of Artificial Lightweight Aggregate(ALA) Concrete (인공경량골재 콘크리트의 배합과 역학적 성상에 관한 실험적 연구)

  • 김화중;김태섭;전명훈;안상건
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1991.04a
    • /
    • pp.99-104
    • /
    • 1991
  • It is necessary to generalize the use for structural ALA Concrete in our country, as increasing in the need for the development of ALA and the use of ALA Concrete which is related with the diminution of the self load and foundation section of structure responding to the realistic requirement against the decrease of natural aggregate and the high-rising and large-sizing of structures. This little study, therefore intended to help in the mixing design of concrete by considering the fundamental properties of ALA Concrete used with expanded clay, which is considered by acopting the experimental factors such as unit cement content, water cement ratio and the rate of fine aggregate. By considering the results of this experiment, it has difficulty in getting expected slump with the unit water content of normal concrete because of the large absorption of lightweight aggregate, and because the weight of unit volume and specific gravity ALA Concrete are small it appears that the strength and Elastic Modulus of that are small too and that it is more ductile than normal concrete.

  • PDF

Optimizing the mix design of pervious concrete based on properties and unit cost

  • Taheri, Bahram M.;Ramezanianpour, Amir M.
    • Advances in concrete construction
    • /
    • v.11 no.4
    • /
    • pp.285-298
    • /
    • 2021
  • This study focused on experimental evaluation of mechanical properties of pervious concrete mixtures with the aim of achieving higher values of strength while considering the associated costs. The effectiveness of key parameters, including cement content, water to cement ratio (W/C), aggregate to cement ratio (A/C), and sand replacement was statistically analyzed using paired-samples t-test, Taguchi method and one-way ANOVA. Taguchi analysis determined that in general, the role of W/C was more significant in increasing strength, both compressive and flexural, than cement content and A/C. It was found that increase in replacing percent of coarse aggregate with sand could undermine specimens to percolate water, though one-way ANOVA analysis determined statistically significant increases in values of strength of mixtures. Cost analysis revealed that higher strengths did not necessarily correspond to higher costs; in addition, increasing the cement content was not an appropriate scenario to optimize both strength and cost. In order to obtain the optimal values, response surface method (RSM) was carried out. RSM optimization helped to find out that W/C of 0.40, A/C of 4.0, cement content of about 330 kg/m3 and replacing about 12% of coarse aggregate with sand could result in the best values for strength and cost while maintaining adequate permeability.

Experimental Study on Mechanical Properties of Carbon-Capturing Concrete Composed of Blast Furnace Slag with Changes in Cement Content and Exposure (고로슬래그 기반 탄소흡수용 콘크리트의 시멘트 첨가율 및 노출조건에 따른 역학적 특성 분석을 위한 실험적 연구)

  • Cho, Hyun Myung;Kim, Seung Won;Song, Ji Hyeon;Park, Hee Mun;Park, Cheol Woo
    • International Journal of Highway Engineering
    • /
    • v.17 no.4
    • /
    • pp.41-51
    • /
    • 2015
  • PURPOSES: This study investigates the mechanical performance of carbon-capturing concrete that mainly contains blast furnace slag. METHODS: The mixture variables were considered; these included Portland cement content, which was varied from 10% to 40% of the blast furnace slag by weight. The specimens were exposed to different conditions such as high $N_2$ and $O_2$ concentrations, laboratory conditions and high $CO_2$ conditions. Mechanical performances, including compressive and flexural strengths and carbon-capturing depth, were evaluated. RESULTS : The slump, air content and unit weight were not affected significantly by the variation in cement content. The strength development when the specimens were exposed to high purity air was slightly greater than that when exposed to high $CO_2$. As the cement content increased the compressive and flexural strength increased but not considerably. The carbon-capturing capacity decreased as the cement content increased. The specimens exposed in the field for 70 days had flexural strength greater than 3 MPa. CONCLUSIONS : The results indicate that cement content is not an important parameter in the development of compressive and flexural strengths. However, the carbon-capturing depth was higher for less cement content. Even after field exposure for 70 days, neither any significant damage on the surface nor any decrease in strength was observed.

Effects of the Water Reducing Agent on the Concrete (減水劑가 콘크리트에 미치는 影響)

  • Kim, Jong-Cheon;Doh, Duk-Hyun
    • Magazine of the Korean Society of Agricultural Engineers
    • /
    • v.24 no.2
    • /
    • pp.67-75
    • /
    • 1982
  • A study on the effect of water reducing agent on the various characteristics of concrete has been conducted. The experimental results of the study are summarized as follows. 1. Slump test for the concrete added water reducing setretarding agent in proper quantity have been conducted. According to the test results, the decreasing rate of slump value become bigger than plain concrete with increase of the unit weight of cement and elapse of time 2. In case the proper quantity content of maximum compressive strength in Fig. 5 of water reducing set retarding agent is added, unit weight of water is decreased about 15% or so as compared with plain concrete. with the increase of water reducing set accelerating agent content unit weight of water is decreased much more, And other hand, amount of air entraining shows the increasing tendency with the increase of water reducing agent content. 3. The adding rate of water reducing agent which produce maximum strength shows that WR-CH and WR-SA which is water reducing set-starding agent is 0.2% and WR-CO is 0.5% and that WS-PO which is water reducing set accelerating agent is 0.5 4. compressive strength jof the concrete made of sulfate resistant cement shows less than the strength of normal portland cement at initial strength but the strength of both cement shows almost same at curing age of 28 days. 5. when proper quantity of water reducing set retarding agent is used, boned strength is increased about 15% at curing age of 28days. 6. According to the result of durability test, dynamic young's mudulus of elasticity at plain concrete is decreased about 50% as compared with initial step at 300 cycle of freezing and thawing after curing age of days. on the contarary the concrete used water reducing agent is decreased less than 7%.

  • PDF

A Study on the Investigation of Performance about Quick Measurement Technology of Unit Water Content at Mixing Factor of High Strength Concrete (고강도 콘크리트의 단위수량 신속 측정기법별 배합요인에 따른 성능 검토에 관한 연구)

  • Yoon, Seob;Jung, Young-Min;Jeong, Yong
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2008.04a
    • /
    • pp.745-748
    • /
    • 2008
  • On investigation about quick measurement technology of unit water at range of W/B=35% in high strength, the average error of the Di-electric constant moisture tester A has measured more than $23.0kg/m^3$ unit water content of design and the average error of the method of unit volume weigh was less than $-9.6kg/m^3$. The average error with mixing factor has influenced with a kind of sand, but had not influenced with unit water content of design. Therefore, it will be for introduce business decide require more than a study about cement, sand, superplasticizer, etc.

  • PDF

A fundamental Study on the properties of Concrete by using the Rapid Hardening Blast Furnace Slag Cement (조강슬래그시멘트를 이용한 콘크리트의 기초물성에 관한 연구)

  • 김진춘;최광일
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1995.04a
    • /
    • pp.72-77
    • /
    • 1995
  • Blast-furnace slag cement has been used widely as a structural material due to the latent hydraulicity of granulated ground blast furnace slag(GGBS)for a long time as The wall as ordinary portland cement. In this study, based on the fundamental investigation on the high strength and high durable concrete using the high fineness GGBS the following remarks can be made. 1) The average desired strenth of concrete is Or=600~800kg/$\textrm{cm}^2$. 2) The above high strength concrete using the high fineness GGBS is more workable than those using only OPC. 3) The adiabatic temperature and drying shringkage decrease, so the density and resistance to sea water attack increase as results. 4)The unit cement content and unit air entrained admixture at the same desired strength of concrete decrease, so the economical high strength concrete can be manufactured from using the high fineness GGBS.

  • PDF

Effect of the Replacement of Fine Particle Cement on Mechanical Properties of the Concrete (미분 시멘트의 치환율 변화가 콘크리트의 역학적 특성에 미치는 영향)

  • Choi, Sung-Yong;No, Dong-Hyun;Kim, Kyung-Min;Park, Sang-Joon;Kwan, O-Bong;Han, Min-Cheol
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2007.11a
    • /
    • pp.133-136
    • /
    • 2007
  • This study investigates mechanical properties of the concrete using fine particle cement which is manufactured by the pulverizing process. The variable factors are 3 types of W/C such as 40, 50, and 60%, 3 types of curing temperature such as 5, 20, and $35^{\circ}C$, and 5types of the replacement of the fine particle cement such as 0, 25, 50, 75, and 100%. The unit water content, S/a and amount of the SP and AE agents to secure the slump and air content is gradually increased in accordance with amount of replacement. It can be confirmed that the delay of the setting time depending on FC content is decreased corresponding to FC content, so the effect of the acceleration to the setting time is expected. The compressive strength corresponding to FC content is proportionally increased, and the growth is confirmed about $30{\sim}40%$ at a day in 50% of FC contents. However, the increase of the strength is gradually decreased in accordance with increasing age.

  • PDF

Physical and Mechanical Properties of Concrete Using Waste Activated Carbon (폐활성탄을 혼입한 콘크리트의 물리.역학적 성질)

  • Kang, Hyun-Soo;Sung, Chan-Yong
    • Journal of The Korean Society of Agricultural Engineers
    • /
    • v.51 no.1
    • /
    • pp.21-26
    • /
    • 2009
  • This study was performed to evaluate the physical and mechanical properties of concrete using waste activated carbon. Materials used were ordinary portlant cement, crushed coarse aggregate, natural fine aggregate, waste activated carbon, and superplasticizer. The substitution ratios of waste activated carbon were 0,1,2,3,4,5,6,7,8,9 and 10%. The unit weight was decreased and water absorption ratio was increased with increasing the waste activated carbon content, respectively. When the substitution ratio of waste activated carbon was 3%, compressive strength, flexural strength and dynamic modulus of elastisity were more higher than that of the ordinary portland cement (OPC), and it was decreased with increasing the waste activated carbon content, respectively. The most effective contents of waste activated carbon was 2% in performance and 4% in practical use Accordingly, waste activated carbon can be used for concrete material.

Influence of the Improveal Grain Shape of Coarse Aggregates on Compactability of High Performance Concrete (굵은 골재 입형 개선이 고성능콘크리트의 충전특성에 미치는 영향)

  • 이승한;김희중;정용욱
    • Journal of the Korea Concrete Institute
    • /
    • v.12 no.4
    • /
    • pp.103-111
    • /
    • 2000
  • The influence of the improvement of grain shape of the coarse aggregate to the unit powder content of concrete and the fine aggregate ratio for the increase of the flowability and segregation resistance of high performance concrete was examined. According to the experimental results, flowability and compacting of concrete presents best states in the S/a which has the smallest 패야 ratio. The coarse aggregate after improvement of grain shape, that has changed from the 0.68 of spherical rate of disk shape to 0.73, led fine aggregate ratio to be down 6% (i.e from 47% to 41%). The improvement of grain shape of the coarse aggregate also led the lowest unit powder content to be down 60kg/㎥ (ie from 530kg/㎥ to 470kg/㎥). And approximate 10% of unit water content has been reduced as unit powder content was down. However, the compressive strength after the improvement of grain shape of the coarse aggregate decreased to 5% due to decrease of adhesiveness of the aggregate and cement paste.

Development of high-performance cement grout for ground heat exchangers (지중열교환기용 고성능 시멘트 그라우트 개발)

  • Lee, Dong-Chul;Yang, Hee-Jung;Jeon, Joong-Kyu;Seo, Shin-Seok;Choi, Yong-Min
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
    • /
    • v.7 no.1
    • /
    • pp.10-16
    • /
    • 2011
  • Performance of ground-source heat pumps (GSHPs) is mainly affected by ground heat exchangers which makes up more than 40% of construction cost. Exact construction and grout as backfill are important, because it is difficult to repair after being installed. As grout materials, bentonite grout material and cement material are used In this paper, thermal conductivity according to mix proportion of cement grout has been experimentally studied. Some variables were set to evaluate thermal conductivities according to change in cement content, unit water ratio, mass per volume of fresh mortar, and aggregate types. From the experimental analysis, high performance cement grout has been proposed.