• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.11a
• /
• pp.571-574
• /
• 2005

This study investigated the strength of concrete to improve construction material with polymer cement mortar. Some mixtures composed of Styrene-Butadiene Rubber(SBR) and Ethylene Vinyl Acetate(EVA) Poly Vinyl Alcohol(PVA) were studied. The three mixtures carried out the physical, mechanical test to determine its properties which a include : compressive, flexural, bond strength test. The test results show that the compressive strength was increased at long-term age when compared to early ages for increasing polymer contents. It was found that flexural strength and bond strength became larger as polymer to cement ratio became higher.

• Advances in concrete construction
• /
• v.3 no.1
• /
• pp.71-90
• /
• 2015

In order to investigate the feasibility and advantage of tuff used as pozzolan in cement-based composite, the representative specimens of tuff were collected, and their chemical compositions, proportion of vitreous phase, mineral species, and rock structure were measured by chemical composition analysis, petrographic analysis, and XRD. Pozzolanic activity strength index of tuff was tested by the ratio of the compression strength of the tuff/cement mortar to that of a control cement mortar. Pozzolanic reaction degree, and the contents of CH and bond water in the tuff/cement paste were determined by selective hydrochloric acid dissolution, and DSC-TG, respectively. The tuffs were demonstrated to be qualified supplementary binding material in cement-based composite according to relevant standards. The tuffs possessed abundant $SiO_2+Al_2O_3$ on chemical composition and plentiful content of amorphous phase on rock texture. The pozzolanic reaction degrees of the tuffs in the tuff/cement pastes were gradually increased with prolongation of curing time. The consistency of CH consumption and pozzolanic reaction degree was revealed. Variation of the pozzolanic reaction degree was enhanced with the bond water content and relationship between them appeared to satisfy an approximating linear law. The fitting linear regression equation can be applied to mutual conversion between pozzolanic reaction degree and bond water content.

• Journal of Korean Association for Spatial Structures
• /
• v.24 no.1
• /
• pp.29-36
• /
• 2024

The paper presents the experimental investigation of RC beams retrofitted with Textile Reinforced Mortar (TRM), featuring enhanced bond capacity. Anchoring systems, including an extension of retrofitting length and the use of chemical anchors, are newly employed to improve the structural performance of the RC beam retrofitted with TRM. For the experimental investigation, a total of seven shear-critical RC beams, with and without stirrups, were designed and constructed. The structural behaviors of specimens retrofitted with the proposed TRM methods were compared to those of non-retrofitted specimens or specimens strengthened with conventional TRM methods. Crack pattern, force-displacement relationship, and absorbed energy were evaluated for each specimen. The experimental results indicate a significant improvement in the shear capacity of the RC beam with the proposed retrofitting method. Therefore, it is concluded that the application of an extended retrofitting length and chemical anchors to the TRM retrofitting method can effectively enhance the bond capacity of TRM, thereby improving the shear performance of RC beams.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1999.10a
• /
• pp.323-326
• /
• 1999

The purpose of this study is to examine the properties of cement mortar with PVA(Poy Vinyl Alcohol) and MC(Methyl Cellulos). In this paper, Water-soluble polymer cement motar using PVA and MC with water-cement ratio of 50%, polymer-cement ratio of 1.0%, 0.8% and a ratio of cement to fine aggregate (size: #5, #7) 2:3 are prepared, and tested for compressive strength, shear bond strength, flow test, penetration and dry-shirinkage.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2003.11a
• /
• pp.557-560
• /
• 2003

This study deals with the method of test for waterproof agent and admixture of cement, and especially, the effect on bond strength between waterproofing layer and mortar or concrete substrate in building construction. Quality of that has been managed according to it of construction standard manual, housing construction manual, 건, and Q until performance of that is specified by law as KS F 4923. Therefore this study focus on the quality and trend for a fatty system and PCM(Polymer Cement Mortar)

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05b
• /
• pp.373-376
• /
• 2006

The purpose of this study was manufactured and evaluated the bond performance of recycled polyethylene terephthalate(PET) bottle fiber reinforced concrete. Four deformed recycled PET bottle fibers were manufactured and pullout test was conducted in accordance with the JCI-SF 8. Test parameters included four different type of fiber geometry and two types of mortar specimens. According to bond test results, it was found that embossing type recycled PET bottle fiber was significant improving the pullout load and interface toughness.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.04a
• /
• pp.181-188
• /
• 2000

This study deals with the method of test for waterproof agent and admixture of cement, and especially, the effect in bond strength between waterproofing layer and mortar of concrete substrate in building construction. The purpose of this study is that it makes the estimation value of bond strength of concrete wall and anticorrosive when coated waterproof agent and admixture of cement as waterproofing materials for durability performance estimation depend on concrete watertighness.

• Earthquakes and Structures
• /
• v.10 no.1
• /
• pp.125-139
• /
• 2016

For seismic retrofitting of masonry walls, the use of fibre reinforced cement-based mortar for bonding the fibre grids can eliminate some of the shortcomings related to the use of resin as bonding material. The results of an experimental testing program on masonry walls retrofitted with fibre reinforced mortar and fibre grids are presented in this paper. Seven squat masonry walls were tested under unidirectional lateral displacement reversals and constant axial load. Steel anchors were used to increase the effectiveness of the bond between the fibre grids and the masonry walls. Application of fibre grids on both lateral faces of the walls effectively improved the hysteretic behaviour and specimens could be loaded until slip occurred in the horizontal joint between the masonry and the bottom concrete stub. Application of the fibre grids on a single face did not effectively improve the hysteretic behaviour. Retrofitting with fibre reinforced mortar only prevented the early damage but did not effectively increase deformation capacity. When the boundaries of the cross sections were not properly confined, midplane splitting of the masonry walls occurred. Steel anchors embedded in the walls in the corners area effectively prevented this type of failure.

• Journal of the Korea Institute of Building Construction
• /
• v.24 no.1
• /
• pp.23-34
• /
• 2024

This research aims to assess the flexural bonding efficacy of polymer-cement composites(PCCs) in mending cracks within reinforced concrete(RC) structures. The study involved infilling PCCs into cement mortar cracks of varying dimensions, followed by evaluations of enhancements in flexural adhesion and strength. The findings indicate that the flexural bond performance of PCCs in crack repair is influenced by the cement type, polymer dispersion, and the polymer-to-binder ratio. Specifically, the use of ultra-high early strength cement combined with silica fume resulted in an up to 19.0% improvement in flexural bond strength compared to the application of ordinary Portland cement with silica fume. It was observed that the augmentation in flexural strength of cement mortar filled with PCCs was significantly more dependent on the depth of the crack rather than the width. Furthermore, PCCs not only acted as repair agents but also as reinforcement materials, enhancing the flexural strength to a certain extent. Consequently, this study concludes that PCCs formulated with ultra-high early strength cement, various polymer dispersions, silica fume, and a high polymer-to-binder ratio ranging from 60% to 80% are highly effective as maintenance materials for crack filling in practical settings.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.3237-3250
• /
• 2011

As the growing concern about environment and earthquake for the concrete structure, many seismic rehabilitation and retrofitting methods have recently been studied but they are not coping enough with the changes of structure, specificly various problems have been found in seismic rehabilitation method - both in exposure or non exposure - when they are implemented to the underground structure, utility conduit, water supply facilities, underground wall, parking lot, road pavement, and elevated structure etc. This study is about the seismic rehabilitation method using environmentally friendly functional inorganic mortar and resilient material, and it is effectively retrofitted seismic performance as it reinforces not only physical strength, but also flexural and bond strength from the resilient material, and it has been analyzed and evaluated when the environmentally friendly functional inorganic mortar and the resilient material are applied so as to countermeasure the effect of earthquake and viable problems and approved for possibility of various applications and wide use.