• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05b
• /
• pp.393-396
• /
• 2006

This study present the experimental research investigating the influence of material factors such as a type or amount of superplasticizer, velocity agent, mineral admixture and steel fiber on the construction performance of fiber reinforced cementitious composites. As for the test results, it was found that the workability of fiber reinforced cementitious composites can be improved when the material factors were matched properly in amount and composition. Furthermore, it was shown that the smaller value of the aspect ratio of fiber improved the workability of fiber reinforced cementitious composites. And the fiber reinforced cementitious composites with better workability showed the enhanced compressive strength and flexural strength.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05b
• /
• pp.53-56
• /
• 2006

To develop more durable concrete deck, performance characteristic test of HPC(High Performance Concrete) mixtures was carried out. The parameters used in this project were ; the mineral admixture details were 4 types such as ordinary portland cement(OPC), 20% fly ash (FA), 20% fly ash and 4% silica fume(FS), and 40% ground granulated blast-furnace slag(BS). Their design compressive strengths were 27MPa and 35MPa respectively. The results showed the compressive strength of concrete did not much affect the durability of concrete. HPC with blast-furnace slag(BS) showed the good durability but was prone to crack. HPC with fly ash(FA) or with fly ash and silica fume(FS) had the good durability and crack resistance.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05b
• /
• pp.641-644
• /
• 2006

Considering properties of the low-heat concrete mixed with the blended cements, the influences compared blended cements with ordinary portland cement made experiments on. (1) Blended cements were superior to OPC in the fresh concrete flow that the use of blended cements reduced chemical admixture. (2) The more the use of additive increase, the more bleeding happens. So it is considered to heights, order, and rate of placement, curing methods and so on. (3) The use of blended cements increase long term strength after 28 days, but decrease early strength and durability. So it is considered to the curing methods and early frost damage, and endurance limit.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.323-324
• /
• 2009

In this study aluminium sulfate, Ca(OH)$_2$, K-R Slag and Na$_2$SO$_4$ were used as active admixtures. The physical properties of active admixtures cement mortar were investigated by flow test and compressive strength. It was found that the resulting active admixtures exhibited the higher compressive strength than OPC mortar up. From the test results, cement mortars added active admixture have a good fundamental property.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.307-308
• /
• 2009

The ultra high strength concrete classed 80 MPa for Lotte Town at pusan has many hydrated materials due to low water to binder ratio and high admixture contents and improved void structure caused by C-S-H gel corresponding to pozzolan and latent hydraulicity of FA and BS. Moreover, durability of the concrete is superior because there was no penetration of carbon dioxide, chloride and chloric ion caused by its fine internal constitution.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.729-732
• /
• 2008

Naphthalenic admixture(PNS) has been widely used as main component of AE reducing agent among superplasticizers for concrete for a long time. However its noxiousness has been appointed because of formaldehyde compound applied during in synthetic process. In this study, AE reducing agent prepared using PNS and substituted-PNS agent(ECO-AEM) without formaldehyde compound added to concrete. For these agent, the basic performance of concrete and ecological affinity properties were evaluated and compared.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2014.05a
• /
• pp.82-83
• /
• 2014

Concrete with self-healing admixture can reduce the crack width by using a compound for chemical reaction with incoming water and carbon dioxide through the crack. Also, concrete with self-healing admixtures can reduce early-age shrinkage crack by using a inorganic expansive agent. In this research, we perform the basic workability test and compressive test. Also, We measure the drying shrinkage of concrete specimen. Finally, we make mock-up (3m X 3m X 0.23m) and monitor the crack width and length for 3 months.

• Journal of the Korean Ceramic Society
• /
• v.27 no.3
• /
• pp.437-443
• /
• 1990

The resistivity of cement paste and mortar for freezing and thawing was investigated for densifying the structure of cement paste and mortor, slag, diatomaceous earth and fly ash as blending materials and superplasticizer were used, and air entraining agent was added to absorb the volume expansion by freezing and thawing reaction. And then the specimens were subjected to freeze-thaw in water. When both of air entraining agent and superplasticizer as additives were mixed to specimens, their freeze-thaw resistance was enhanced by the air entraining effect and the water reduction effect. When 4% of slag were added to cement, freeze-thaw resistance was especially excellent. In addition, it was found that the specimens with blending materials were more influenced by curing periods than those without admixture. It is assumed that the curing periods contribute to exibit the potential hydraulicity and pozzolanic reactivity of blending materials and to densify their texture.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.10a
• /
• pp.138-143
• /
• 2000

In this paper, we carried out experiment to use crushed waste glass as a fine aggregate. This study delt with the comparative analysis on the construction works and engineering properties of concrete containing crushed waste glass through physical experiment. The experimental variables are crushed waste glass substitution ratio and W/C(38, 53%). When the W/C was 38%, we could know that concrete containing crushed waste glass was good as general concrete on the construction works and engineering properties but the concrete containing crushed waste glass applied W/C 53% was not good as general concrete on those. Therefore, concrete containing crushed waste glass applied W/C 53% should use admixture on the site.

• Magazine of the Korea Concrete Institute
• /
• v.5 no.1
• /
• pp.165-173
• /
• 1993

본 연구는 고강도 콘크리트 실용화의 일환으로 국내에서 시판되고 있는 고성능 감수제의 품질성능을 평가하기 위한 것이다. 이러한 연구를 위하여 8종류의 고성능 감수제를 대상으로 첨가량에 따른 특성을 비교하였다. 또한 경시변화에 따른 특성을 비교, 분석하기 위하여 슬럼프, 공기량 그리고 압축강도비를 측정하였다. 이 때 고성능 감수제의 품질성능 평가 규준는 JASS 5T-402 규준에 따라 실시하였다. 실험결과 국내에서 시판되는 고성능 감수제는 공기량, 앞축강도비에 대해서는 모두 만족하였지만 슬럼프 경시 저하량은 DA를 제외한 모든 고성능 감수제가 규준치를 초과하였다. 따라서 현장에서 고강도콘크리트를 생산할 경우 배합방법이나 첨가방법을 개선하여 시공성을 확보하는 방안이 필요할 것이다.