• Journal of the Korea institute for structural maintenance and inspection
• /
• v.20 no.2
• /
• pp.26-33
• /
• 2016

The alkali-slag-red mud(ASRC) cement belongs to clinker free cementitious material, which is made from alkali activator, blast-furnace slag(BFS) and red mud in designed proportion. This study is to investigate strength and pore characteristics of alkali-activated slag cement(NC), clinker free cementitious material, and ordinary portland cement(C) mortars using polymer according to red mud content. The results showed that the hardened alkali-activated slag-red mud cement paste was mostly consisted of C-S-H gel, being very fine in size and extremely irregular in its shape. So the hardened ASRC cement paste has lower total porosity, less portion of larger pore and more portion of smaller pore, as compared with those of hardened portland cement paste, and has higher strength within containing 10 wt.(%) of alkali-activated slag cement(NC) substituted by red mud.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.11a
• /
• pp.807-810
• /
• 2005

In this study, MMA-modified paste of coating material for protecting the concrete structures was developed. The coating material was applied to cement concrete specimens by brush, roller and spray in each of which one, two and three layers to survey, by the cold-hot iterative test, the neutralization test, the chloride ion permeation test and the ante-abrasion test, the affect of painting methods and layers influencing on the durability of coating material. Results of the cold-hot iterative test showed that, regardless of the painting methods and layers, the defects such as crack or fuzz on surface were not produced. As the number of painting layers increased, the neutralization prevention as well as the chloride ion permeation prevention effects were increased. On the other hand, no difference was found between the painting methods. Reducing weight by abrasion of polymer paste coating material was $20\%$ comparing to that of cement mortar.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2014.05a
• /
• pp.124-125
• /
• 2014

Polymer concrete has more excellent durability, tensile strength, flexural strength and waterproof performance mechanically than normal concrete, and as it mixes as a polymer binding material, it can reduce the cement use amount. This study reviews fundamental properties of cement material mixed with complex polymer. As a result of this study, as percentage of complex polymer mix increases, flow value will decrease so that liquidity and compression strength will decrease. On the other hand, in case of flexural strength, when the mixture is 10%, it increases significantly more than OPC.

• Carbon letters
• /
• v.23
• /
• pp.22-29
• /
• 2017

The compressive strength and electrical resistance of pitch-based carbon fiber (CF) in cementitious materials are explored to determine the feasibility of its use as a functional material in construction. The most widely used CFs are manufactured from polyacrylonitrile (PAN-based CF). Alternatively, short CFs are obtained in an economical way using pitch as a precursor in a melt-blown process (pitch-based CF), which is cheaper and more eco-friendly method because this pitch-based CF is basically recycled from petroleum residue. In the construction field, PAN-based CFs in the form of fabric are used for rehabilitation purposes to reinforce concrete slabs and piers because of their high mechanical properties. However, studies have revealed that construction materials with pitch-based CF are not popular. This study explores the compressive strength and electrical resistances of a cement paste prism using pitch-based CF.

• Applied Chemistry for Engineering
• /
• v.22 no.4
• /
• pp.423-428
• /
• 2011

Hydration characteristics of cement containing zeolite mined at Daepo in Gyeongbuk province were studied for use as a mineral admixture. The cement paste containing zeolite was characterized by the measurement of heat evolution, XRD, EDS, nitrogen adsorption and mercury intrusion porosimetry. The cement paste containing zeolite exhibited tendencies toward acceleration of paste setting and promotion of cement hydration with the increase of zeolite content. The flow of mortar containing zeolite strongly reduced with increase of zeolite content. Compressive strength of the mortar containing zeolite increased very rapidly at an early age in comparison with plain mortar. These results would be related to aluminum species escaped from zeolite particles during the alkali dealumination of zeolite by the hydration process of cement.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2005.10a
• /
• pp.97-101
• /
• 2005

High strength concretes utilizing EVA with micro particles were prepared by varying polymer/binder mass ratio and curing conditions with a constant water/binder mass ratio of 0.3. The EVA modified concretes on the compressive and flexural strength, microstructure, ultrapulse modulus in curing condition(dry and water curing) were studied. Also, scanning electron microscope analysis(SEM) was performed to reveal the presence of polymer film and cement hydrates in the concrete. The compressive strength of the EVA modified concretes cured at water conditions ere higher than that of the EVA modified concretes cured at dry conditions. But, the flexural strength of the specimens cured at dry conditions were higher than that of the specimens cured at water conditions. Due to the interaction of the cement hydrates and polymer film, an interpenetrating network originated in which the aggregates were embedded. The curing of the polymer modified concrete involves two step of cement hydrates and polymer modification, and cement hydrates was promoted in water conditions and polymer film formation take place when water evaporates and was thereby was favored in dry conditions. By SEM analysis, influences of polymer modification was strengthening of the transition zone between the aggregate and the paste, and the porosity of transition zone decreases. By spring analysis, it could known that polymer film affects in porosity decrease and strengthening of transition zone.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.11a
• /
• pp.929-932
• /
• 2006

The effects of polymer-binder ratio, antifoamer content and shrinkage-reducing agent content on the setting time and drying shrinkage of high-fluidity polymer-modified pastes are examined. As a result, the setting time of the high-fluidity polymer-modified pastes tends to delayed with increasing polymer-binder ratio. Irrespective of the antifoamer content, the drying shrinkage of the high-fluidity polymer-modified pastes tend to decrease with increasing polymer-cement ratio and shrinkage-reducing agent content.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2023.11a
• /
• pp.217-218
• /
• 2023

This study is to develop porous concrete using super absorbent polymer, which possesses insolubility and high absorption capacity, as a substitute material for lightweight soil. Various mixtures were prepared using aggregates, cement, mixing water, and super absorbent polymer, and the absorption ratio and compressive strength were examined for each mixture. As the amount of super absorbent polymer added increased, the absorption ratio also increased, reaching up to 35-105%. However, the compressive strength decreased by 49.5% to 65.3%. This is believed to be due to the inherent properties of super absorbent polymer, which led to an increase in the absorption ratio but, in turn, reduced the binding strength of cement paste particles, resulting in a decrease in compressive strength.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2004.11a
• /
• pp.15-15
• /
• 2004

• Advances in concrete construction
• /
• v.15 no.2
• /
• pp.75-84
• /
• 2023

Currently, polymer matrix nanocomposites (PMCs) are a prominent area of research due to their outstanding mechanical, thermal, and durability properties. The increase in recent studies justifies the possibility of using PMCs in structural retrofitting and reconstruction of damaged infrastructure and serving as new structural material. Using nanotechnology, nanocomposite panels in flooring combine concrete and steel, providing a very high level of performance. In sports flooring, high-performance concrete has become a challenge for reducing sports injuries and refinement in rehabilitation. As a composite material, this type of resistant concrete is one of the most durable and complex multi-phase materials. This article uses polyvinyl alcohol polymer (PVC) and multi-walled carbon nanotubes as concrete matrix fillers. Solution methods have been used for dispersing PVC and carbon nanotubes in concrete. The water-cement ratio, carbon nanotube weight ratio, and heat treatment parameters influenced the concrete nanocomposite's tensile and compressive strength. The dispersion of carbon nanotubes in cement paste and the observation of nano-microcracks in concrete was evaluated by scanning electron microscope (SEM).