• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.05b
• /
• pp.45-48
• /
• 2005

Self compacting concrete has the strong point in capability of concrete to be uniformly filled and compacted in every corners of formwork by its self-weight without vibration during placing. However, powder type self compacting concrete has the weak point in the heat of hydration, the drying shrinkage and the elastic property of concrete etc. Recently viscosity agent has been developed in order to overcome these weaknesses. In this study, self compacting concrete is made with viscosity agent based on polysaccharide derivative in order to develope the normal strength self compacting concrete. Slump flow, loss of slump flow and setting time are measured for comparison with normal concrete. Compressive strength, freezing and thawing test and carbonation test are conducted on normal and self compacting concrete using viscosity agent. In the experiment, we acquired good results in fresh and hardened self compacting concrete using viscosity agent based on polysaccharide derivative.

• Computers and Concrete
• /
• v.20 no.6
• /
• pp.655-661
• /
• 2017

Fiber reinforced concretes exhibit higher tensile strength depending on the percent and type of the fiber used. These concretes are used to reduce cracks and improve concrete behavior. The use of these fibers increases the production costs and reduces the compressive strength to a certain extent. Therefore, the use of fiber reinforced concrete in regions where higher tensile strength is required can cut costs and improve the overall structural strength. The behavior of fiber reinforced concrete and normal concrete adjacent to each other was investigated in the present study. The concrete used was self-compacting and did not require vibration. The samples had 0, 1, 2 and 4 wt% polypropylene fibers. 15 cm sample cubes were subjected to uniaxial loads to investigate their compressive strength. Fiber Self-Compacting Concrete was poured in the mold up to 0, 30, 50, 70 and 100 percent of the mold height, and then Self-Compacting Concrete without fiber was added to the empty section of that mold. In order to investigate concrete behavior under bending moment, concrete beam samples with similar conditions were prepared and subjected to the three-point bending flexural test. The results revealed that normal Self-Compacting Concrete and Fiber Self-Compacting Concrete may be used in adjacent to each other in structures and structural members. Moreover, no separation was observed at the interface of Fiber Self-Compacting Concrete and Self-Compacting Concrete, either in the cubic samples under compression or in the concrete beams under bending moment.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.208-211
• /
• 2004

In order to obtain improved concrete mix proportion on nuclear power plant structures, the properties of normal concrete is compared with self-compacting concrete. In addition, various mixes of self-compacting concrete utilizing melaminic acid based admixture is mutually compared and estimated. Because existing normal concrete mixes might occur high temperature in concrete structure, A new multi-component concrete, which declines hydration heat, is demanded. Therefore, in this study, the possibility of manufacturing self-compacting concrete is verified and what influences melaminic acid and various powders have on the properties of self-compacting concrete are investigated.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.497-500
• /
• 2008

This research carries out experiments for hydration exothermic rate and adiabatic temperature rise of concrete to examine the characteristics of the hydration heat of high flowing self-compacting concrete with a normal strength. As a result of the hydration exothermic rate experiment, the high flowing self-compacting concrete that used Lime stone powder and fly ash as polymers shows that its hydration heat amount reduces due to the reduction of unit cement. The result measured the adiabatic temperature rise of concrete presents that high flowing self-compacting concrete having lots of binder contents has a good performance in temperature reduction due to the effect of polymer and that triple adding high flowing self-compacting concrete has a similar temperature rise speed with conventional concrete. As a result of the research, high flowing self-compacting concrete shows a better temperature reduction performance for the binder content per unit than conventional concrete. In addition, it is judged that triple adding high flowing self-compacting concrete with a specified concrete strength 30 MPa is more beneficial in temperature reduction and early hydration heat than double adding high flowing self-compacting concrete.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.204-207
• /
• 2004

In this paper, mechanical properties of the high strength lightweight self-compacting concrete with simple mixed design method was investigated. Experimental tests were performed as such compressive strength, splitting tensile strength, modulus of elasticity and density of high strength lightweight self-compacting concrete. The 28 days compressive strength of high strength lightweight self-compacting concrete with the LC replacement ratio of $100\%$ reduces about $31\%$ but LF replacement ratio of $100\%$ increase about $20\%$ compared that of the control concrete. The structural efficiency of high strength lightweight self-compacting concrete increase with proportional to the replacement into of LF. The relationship between the splitting tensile strength and 28 days compressive strength can be represented by the equation $f_s=0.076f_{ck}+0.5582$. The modulus of elasticity was found to be lower than that of normal weight concrete, ranging form 24 to 33 GPa.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.05a
• /
• pp.73-78
• /
• 2002

This study examines self-compacting of concrete using Ground Calcium Carbonate(GCC) gathering in limestone mine of Banyans district in order to make self-compacting concrete in the range of design strength 300kgf/cm$^2$ and the optimal mix proportion of self-compacting concrete that can use in field structure. The result shows that the optimal GCC replacement ratio is 45$\pm$5% in the normal strength of design strength 300kgf/cm$^2$ and that the volume ratio of the optimal fine aggregate used as the way satisfying both viscosity and compacting ability without separating materials is 46%. The optimal volume ratio of the coarse aggregate considering the economical aspect of concrete is 50%. It is desirable that the optimal mix proportion satisfying self-compacting for replacement of GCC is decided through mix design according to each replacement ratio.

• Structural Engineering and Mechanics
• /
• v.58 no.1
• /
• pp.143-161
• /
• 2016

Utilization of mineral and chemical admixtures in concrete technology has led to changes in the formulation and mix design in recent decades, which has, in turn, made the concrete stronger and more durable. Lightweight concrete is an excellent solution in terms of decreasing the dead load of the structure, while self-compacting concrete eases the pouring and removes the construction problems. Combining the advantages of lightweight concrete and self-compacting concrete is a new and interesting research topic. Considering its light weight of structure and ease of placement, self-compacting lightweight concrete may be the answer to the increasing construction requirements of slender and more heavily reinforced structural elements. Twenty one laboratory experimental investigations published on the mix proportion, density and mechanical properties of lightweight self-compacting concrete from the last 12 years are analyzed in this study. The collected information is used to investigate the mix proportions including the chemical and mineral admixtures, light weight and normal weight aggregates, fillers, cement and water. Analyzed results are presented in terms of statistical expressions. It is very helpful for future research to choose the proper components with different ratios and curing conditions to attain the desired concrete grade according to the planned application.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.212-215
• /
• 2004

While member sections of concrete structures of nuclear power plant are big, water-cement ratio is small. Consequently, the huge amount of heat generation and high viscosity could be occurred. These might reduce constructibility of nuclear power plant. In order to obtain improved concrete mix proportion on nuclear power plant structures, the properties of normal concrete is compared with self-compacting concrete. In addition, various mixes of self-compacting concrete utilizing polycarboxylic acid based admixture is mutually compared and estimated.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.10a
• /
• pp.561-566
• /
• 2002

Recently, high quality exposed concrete is needed to achieve high quality surface for outer wall of the building. In this study, to solve above characteristic of the exposed concrete we selected self compacting concrete(SCC) and compared with normal concrete. So, we developed the SCC mix design and performed the semi mock-up test. Through this result, we performed the pilot test and mock-up test to check surface of outer wall and to measure formwork pressure As a result because SCC is better than normal concrete with respect to flowability and seggregation resistance SCC is suit to a exposed concrete needed high quality surface for outer wall of the building.

• Advances in materials Research
• /
• v.7 no.1
• /
• pp.45-72
• /
• 2018

In the present study, a special attention has been paid to the effects regarding the use of different superplasticizers in different dosages. To do so, 36 mixes of normal and self-compacting concrete with two water/binder ratios of 0.35 and 0.45, four different types of superplasticizer including melamine-formaldehyde, naphthalene-formaldehyde, carboxylic-ether and poly-carboxylate, four different superplasticizer/cement ratios of 0.4%, 0.8%, 1.2% and 1.6% and two silica fume/cement ratios of 0% and 10% have been cast. Moreover, the initial and final setting time of the pastes have been tested. For self-compacting mixes, flow time, slump flow, V-funnel, J-ring and L-box tests have been carried out as well as testing the compressive strength and rupture modulus. For normal concrete mixes,slump test has been conducted to assess the workability of the mix and then for each mix, the compressive strength and rupture modulus have been determined. The results indicate that in addition to the important role of superplasticizer type and dosage on fresh state properties of concrete, these parameters as well as the use of silica fume could affect the hardened state properties of the mixes. For instance, the mixes whose superplasticizer were poly-carboxylic-ether based showed better compressive and tensile strength than other mixes. Besides, the air contents showed robust dependency to the type of the superplasticizer. However, the use of silica fume decreased the air contents of the mixes.