Polymer Cement Mortar Research Articles

유화제 및 단량체비에 따른 스티렌-부틸 아크릴레이트계 폴리머 시멘트 모르타르의 특성

본 연구는 시멘트 혼화용 폴리머를 스티렌과 부틸 아크릴레이트를 단량체로 이용하여 유화제의 첨가량을 달리하여 합성제조하고 제조된 폴리머를 시멘트 모르타르에 혼입하여 그 특성을 파악함으로써 시멘트 혼화용으로써의 사용가능성을 확인하고자 하는 기초적 실험이다. 유화제 첨가량과 단량체비를 달리하여 스티렌-부틸 아크릴레이트(styrene/butyl acrylate)계 폴리머 시멘트 모르타르의 특성은 물-시멘트 비, 공기량, 강도, 방수성 및 염화물 이온 침투저항성을 측정하여 그 특성을 파악하고자 하였다. 연구 결과 보통 시멘트 모르타르에 비해 유화제의 첨가량이 6%일 때, S/BA의 단량체비가 60:40일 때 우수한 강도특성을 나타냈으며, 방수성과 염화물 이온 침투 저항성에서는 유화제의 첨가량과 단량체비보다는 폴리머-시멘트 비에 의해 크게 개선되는 것을 알 수 있었다. 따라서 S/BA를 시멘트 혼화용으로 혼입한 폴리머 시멘트 모르타르의 현장적용이 가능할 것으로 판단되었다. The purpose of this study is to clarify the effect of the emulsifier ratio on the properties of the polymer cement mortars based on styrene-butyl acrylate (S/BA) latexes, and to obtain necessary basic data to develop appropriate latexes for cement modifiers. The polymer dispersions for cement modifiers was synthesized using styrene and butyl acrylate. Polymer cement mortars based on S/BA latexes were prepared with various monomer and emulsifier ratios, and their water-cement ratio, air content, flexural and compressive strengths, water absorption and chloride ion penetration were tested. From the test results, the maximum flexural and compressive strengths of polymer cement mortars based on S/BA latexes were obtained at a bound styrene content of 60% and an emulsifier ratio of 6%. Also, the water absorption and chloride ion penetration depth are greatly affected by the polymer-cement ratio rather than the bound styrene and emulsifier content. Accordingly, it is judged that S/BA latexes can be used place of the conventional polymer dispersions of cement modifier.

膨れを防止する塗り床材用コンクリート下地調整材料の開発

Epoxy floor coatings blistering sometimes occur when those are applied on concrete substrate. One of cause on this phenomenon was considered to be osmotic pressure owe to water in concrete. Recently in order to prevent epoxy floor coatings from blistering, some polymer cement mortar as underlayment material is often applied on concrete substrate, and epoxy floor coatings are applied on this underlayment one. But those polymer cement mortar is not effective in preventing epoxy floor coatings from blistering perfectly. So at first we have studied the relationship between epoxy floor coatings blistering and concrete substrate property. And on the base of those study consequence, we have developed new polymer cement mortar material to prevent epoxy floor coatings from blistering most perfectly. This material as underlayment was tested for adhesive strength to epoxy floor coatings, and performance of preventing epoxy floor coatings from blistering according to accelerating blistering test method. From the test results, their excellent performance is confirmed.

鉄筋コンクリート造そで壁付き柱の簡略的骨格曲線の評価

This paper proposes a seismic retrofitting technique for existing RC columns with cast-in-place RC sidewall using polymer-cement mortar (PCM). In the technique, additional shear reinforcement (deformed steel bar: prefabricated reinforcing unit) is adhered to the surface of existing RC columns with RC sidewall by PCM. Shear-loading tests were conducted to clarify the structural performance of the columns with sidewall strengthened by polymer-cement mortar. The results suggested that the capacity and ductility of the strengthened RC column with RC sidewall could be controlled by choosing the strengthened area and the amount of shear reinforcement. Furthermore, the shear force Q &mdash drift angle R curve of RC columns with RC sidewalls retrofitted by RCM was proposed by considering the shear resistance mechanism.

Effect of Polymer on Antifreeze Properties of Cement Mortar

Owing to the disadvantages of traditional mortar with poor antifreeze property，low adhesive strength and short durability in the cold region of China, the facing tiles often fall off and lead to the lost of decorative effects and protective effects. In this article，a new type of mortar for exterior wall facing tile，polymer cement mortar modified by polymer, is introduced. The advantages of the new mortar are: (l) Better frost resistance，which is reflected by stability after one hundred cycles of freezing and thawing; (2) Higher adhesive strength (2.0MPa); (3) Better permeability resistance and longer durability. It is believed that an ideal building mortar for the resistance of frost damage and suitable for exterior wall facing tile.

Polymer action on alkali–silica reaction in cement mortar

Due to the improvement of several properties, such as lower water absorption and increasing resistance to microcracking, polymer modification of mortar and concrete potentially leads to an inhibiting effect on alkali–silica reaction (ASR). In this study, polymer–cement mortars (PCMs) were subjected to accelerated alkali reactivity tests and their performance compared to that of an unmodified cement mortar (CM). Expansion of PCMs was overall higher, but SEM observations revealed apparent lower microcracking intensity of the cement paste, compared to the unmodified CM. Subsequent stiffness damage tests (SDTs) quantified the existing damage after alkali reactivity tests and confirmed the lower microcracking intensity in PCMs.

친환경 콘크리트 개발을 위한 고분자 화합물의 적용에 관한 연구

본 연구는 수용성 폴리머의 일종인 폴리비닐아세테이트(Polyvinyl Acetate, 이하 PVAc)를 사용한 폴리머 시멘트 모르타르와 콘크리트의 특성에 관한 평가를 통하여 친환경 콘크리트 개발을 위한 기초자료를 획득하는 것이다. 이를 위해 PVAc를 혼입하지 않은 시멘트 모르타르 및 콘크리트와 결합재 대비 3%, 6%, 9%, 12%의 PVAc를 각각 혼입한 폴리머 시멘트 모르타르 및 콘크리트와의 비교분석을 통한 물리적 특성을 평가하였으며, 폴리머 혼입에 따라 늘어나는 공기량을 제어하기 위해 소포제를 첨가하여 PVAc 콘크리트의 특성을 평가하였다. 그 결과 PVAc가 혼입된 폴리머 시멘트 모르타르의 경우 압축강도는 낮아지나 휨강도와 건조수축의 성능이 향상되는 것으로 나타났으며, 콘크리트의 경우 혼입율이 6%일 때가 압축강도, 인장강도, 휨강도 및 탄성계수가 높아지는 것을 확인할 수 있었다. The objective of this paper is to obtain the basic data in order to develop an eco-friendly concrete through evaluation on the properties of polymer cement mortar and concrete using PVAc (Polyvinyl Acetate), as a kind of water-soluble polymer. For this purpose, the physical properties of cement mortar and concrete which does not contain the PVAc as the control batch were compared and analyzed with those using the PVAc. And then, the replacement amount of the PVAc was 3%, 6%, 9% and 12% by binder, respectively. And also, the properties of concrete using the PVAc were evaluated, by adding an antifoaming agent in order to control the air contents increasing with an increase of amount of polymer usage. As a result, in the case of polymer cement mortar using the PVAc, it presented that the compressive strength reduced, while the performance of flexural strength and drying shrinkage increased. When the replacement of the PVAc was 6% within concrete, the compressive, tensile, flexural strength and elastic modulus were increased.

Fracture Mechanisms of Polymer Cement Mortar: Concrete Interfaces

Laboratory tests, including splitting tension, three-point bending, and direct shear tests, were conducted on polymer cement mortar (PCM)-concrete composite specimens with various degrees of interface roughness (Ra). The PCM-concrete bond strength, fracture energy, and fracture surface were investigated qualitatively. The failure mode and the condition of the fracture surface significantly affected the interface bond strength and fracture energy. The bond strength and fracture energy were found to increase with increasing interface roughness until the fracture location shifted from the PCM-concrete interface to within either the PCM or the concrete. The interface roughness has a greater influence on the interface fracture energy and the flexural strength than on the tensile and shear strengths. Considering the single mode (Mode I or Mode II) bond and fracture properties, as well as retrofitting costs, a roughness index of approximately 1 mm (0.9≤Ra≤1.1 mm) is proposed as the optimum value of interface roughness, and the corresponding recommended treatment is water-jetting (WJ) to a depth of 2–2.5 mm. Finally, an interfacial tension softening model that takes into account the effects of fracture energy, tensile strength, and failure mode is presented.

Effect of epoxy resin on the intrinsic properties of masonry mortars

The paper presents an assessment on the properties of three different types of masonry mortars, namely Portland cement mortar (CM), polymer cement mortar (PCM) and polymer mortar (PM) of various compositions. The effect of binder content (cement and/or epoxy) on CM, PCM or PM has been explored in the study. An assessment was carried out on the basis of mechanical (compressive, tensile and flexural strength), physical (water uptake, chloride ion permeability), morphological (porosity) and thermal (coefficient of thermal expansion) properties of the mortars. A comparative cost analysis of the mortars is also discussed in this article. The results show that the mechanical strength of both PCM and PM improves markedly with the addition of epoxy resin, and the higher rate of incremental strength is found for PM. Consequently, the chloride ion penetration, water uptake, porosity and thermal expansion of the mortars decrease significantly with the resin content, but the rate of drop in chloride ion penetration, water uptake, porosity and thermal expansion is much higher for PM. The test results indicate that the variation of binder content (epoxy/cement) is found to be the key factor determining the mortar properties and cost.

鉄筋コンクリート造そで壁付き柱のせん断耐力評価

This paper proposes a seismic retrofitting technique for existing RC columns with cast-in-place RC sidewall using polymer-cement mortar. In the technique, additional shear reinforcement (deformed steel bar: prefabricated reinforcing unit) is adhered to the surface of existing RC columns with RC sidewall by using polymer-cement mortar. Shear-loading tests of the RC columns with RC sidewall were conducted to clarify the structural performance of the columns with sidewall strengthened by polymer-cement mortar. The results suggested that the technique improved the shear capacity of the RC columns with RC sidewall, and clarified the mechanism of shear resistance of the strengthened columns with sidewall. Furthermore, a method of estimating the shear strength of RC columns with RC sidewall strengthened by polymer-cement mortar was proposed by modeling the shear resistance mechanism.

SHEAR CAPACITY EVALUATION OF RC BEAMS STRENGTHENED BY UNDERSIDE OVERLAY METHOD USING HIGH-PERFORMANCE POLYMER CEMENT MORTAR

In this study, the new strengthening method of spraying high-performance PCM (polymer cement mortar) onto the underside of existing beams was adopted. The underside of the RC (reinforced concrete) beams was strengthened between two support points except 50mm nearly the supports. This experiment assumed application to a RC highway bridge slabs and beams. These RC beams were tested to determine the shear capacity and shear failure mode of this overlay method. Loading tests were carried out on the RC beams with changes in the reinforcement ratio, effective depth, and shear span-to-effective depth ratio. As a result, RC beams without web reinforcement strengthened by the underside sprayed-on overlay method using high-performance PCM reached diagonal tension failure without any slip in the interface between the existing concrete and PCM. Based on the test results, it was considered that the mechanism of shear resistance of the beams strengthened by this overlay method was supported by two compressive paths; one was the path toward main reinforcement in the existing concrete, the other was toward reinforcement in the PCM from a macroscopic perspective. An experimental formula for shear capacity considering two compressive paths has been proposed by modifying existing Niwa's formula of shear capacity for normal reinforced concrete beams without web reinforcement. This formula facilitates the design for beams strengthened using the overlay spraying method using high-performance PCM. It is necessary to examine the value of safety factor as a future problem more. In addition, it was revealed that the high toughness of PCM did not contribute to the improvement of the shear capacity.高靭性ポリマーセメントモルタルを用いた吹付け施工により下面増厚補強したRCはりの補強効果とせん断耐力について実験的に検討した。RCはり供試体は道路橋のRC床版やRC桁への適用を想定し、RCはりの支点手前50mmの範囲は下面増厚を施していない。有効高さ、せん断スパン比、主鉄筋比、補強鉄筋比をパラメータとする下面増厚補強RCはりのせん断耐力実験を行い、補強効果を検証するとともに、せん断破壊過程から土木学会（二羽式）のせん断耐力式における有効高さの取り扱いを考察し、せん断耐力の評価法について検討した。

Long-Term Bonding Strength between Flue Gas Desulfurization Gypsum and Polymer Cement Mortar

The uncertainty of long-term bonding strength of flue gas desulfurization building gypsum and cement based construction materials is the major issue impeding the application of flue gas desulfurization building gypsum in construction. A polymer cement mortar is suggested to get high bonding quality with flue gas desulfurization building gypsum. Long-term bonding observation has been carried out to verify the bonding performance of suggested polymer cement mortar with flue gas desulfurization gypsum. The results show that the bonding strength is up to 3.0MPa, and the bonding between them is durable.

Long-Term Bonding Strength between Flue Gas Desulfurization Gypsum and Polymer Cement Mortar

The uncertainty of long-term bonding strength of flue gas desulfurization building gypsum and cement based construction materials is the major issue impeding the application of flue gas desulfurization building gypsum in construction. A polymer cement mortar is suggested to get high bonding quality with flue gas desulfurization building gypsum. Long-term bonding observation has been carried out to verify the bonding performance of suggested polymer cement mortar with flue gas desulfurization gypsum. The results show that the bonding strength is up to 3.0MPa, and the bonding between them is durable.

AN EXPERIMENTAL STUDY ON FLEXURAL STRENGTHENING METHODS OF REINFORCED CONCRETE BEAMS USING HIGH-TOUGHNESS POLYMER CEMENT MORTAR AND CONTINUOUS FIBER REINFORCEMENTS

In this study, experimental investigations were conducted regarding flexural strengthening of reinforced concrete (RC) beams using high-toughness polymer cement mortar (HTPCM) and continuous fiber reinforcements. Our results showed that using the HTPCM as section recovering and thickening materials is effective in improving flexural strengthening effect of continuous fiber sheets/plates and rods on RC beams, because diagonal tensile cracking in tension-side covering concrete and bond-splitting failure of thickened part are prevented by the HTPCM. Furthermore, it was also shown that the flexural strengthening effect does not remarkably decline by upward execution, if plastering thickness of HTPCM of one time is adjusted to 6 mm or less.

Light Polymer Cement Mortar Pavement for Orthotropic Steel Bridge Decks

The mechanical behavior of pavement on orthotropic steel bridge deck with rib stiffener, longitudinal clapboard and diaphragm was analyzed at first by finite element method. It shows that the larger the elastic modulus of the intermediate layer, the less stress in the critical fatigue parts of the surfacing and the more favorable to the whole deck pavement. So it is necessary to exploit a stiffer cement-based transition layer to improve the mechanical condition between bridge deck and pavement. Then, in terms of the advantage and great achievements of light concrete and polymer modified cement concrete in civil engineering, reasonable materials were selected and their mixing ratios were designed to prepare light polymer cement mortar (LPCM) with both advantages suitable for transition layer for the steel bridge deck pavement. And compressive strength, flexural strength, fatigue performance, characteristics of stress-strain curves and modification mechanism were analysed. The results turn out that (1) the density of the developed mortar is about 1,800 kg/m³ and the mortar is light mortar; (2) acrylic acid emulsion can decrease water-cement ratio, improve paste working property, increase flexibility and crack resistance of the mortar, and there is a best dosage. Mechanism analysis shows that high-tensile strength of the polymer membrane is the basic reason to significantly improve LPCM mechanical properties. It means that light polymer mortar is an excellent flexible cement composing material and it can be used at some place where thickness, weight and flexibility have special requirement such as bridge deck pavement, etc.

Preparation of Flexible Polymer-Cement Mortar

A new flexible polymer-cement mortar was prepared by adjusting the ratio of cement, polymer emulsion and solution. The effects of cement and different kinds of polymer emulsion on the construction performance of composite materials such as workability, anti-aging, flexibility and impact resistance were evaluated. It was indicted that the prepared flexible polymer-cement mortar possessed a good application prospect.

시험시공을 통한 친환경 고성능 3성분계 시멘트 콘크리트 교면 포장의 성능 평가

This study experimented to evaluate the environment friendly high performance ternary cement concrete deck overlay pavement using mineral admixture such as fly ash and ground granulated blast-furnace slag. It was measured to find best binder mixing according to replacement rate of mineral admixture with compressive strength and flexural strength. After finding best binder, it is also experimented to evaluate durability on chloride penetration resistance, freezing- thawing resistance, scaling resistance of deicing chemicals, abrasion resistance, alkali-silica reactivity test and bonded environment friendly high performance ternary cement concrete deck overlay pavement experimented to evaluate bonded old deck and new concrete overlay pavement using special polymer cement mortar. In additions, bonded environment friendly high performance ternary cement concrete deck overlay pavement by experimental construction was evaluated at interchange bridge of North Yeoju. Result, examination was indicated better binding with binder replacement of cement 70%, ground granulated blast-furnace slag 15% and fly ash 15%. And special polymer cement mortar used in old deck and new overlay concrete was indicated better bonding both laboratory and construction.

Thermal characteristics of high-strength polymer–cement composites with lightweight aggregates and polypropylene fiber

Recently, research has been conducted using fibers to reduce the explosive spalling of concrete. Assessments of the volume fraction of polypropylene fiber in high-strength and lightweight concrete has shown that an optimum volume fraction of fiber reduces explosive spalling by discharging pore pressure and heat stress inside the concrete through the dissolution of fibers during exposure to high temperatures. In this study, we manufactured a high-strength polymer–cement mortar that can be used in repairs of many concrete structures by selecting three kinds of lightweight aggregate that have excellent heat interception performance, combined with varying volume fractions of polypropylene fiber to reduce explosive spalling. We analyzed the thermal characteristics and physical and mechanical properties of the mortar at high temperature. The analysis of test results for compressive strength, flexural strength, thermal conductivity, and thermogravimetric showed that a mixture of expanded perlite with high thermal stability and 0.2% polypropylene fiber showed the best physical, mechanical, and thermal characteristics.

組立鉄筋と特殊ポリマーセメントモルタルを用いた鉄筋コンクリート造そで壁付柱の耐震補強工法の概要

組立鉄筋と特殊ポリマーセメントモルタルを用いた鉄筋コンクリート造そで壁付柱の耐震補強工法の概要

Stress transfer mechanism of the reinforced interface and seismic retrofit existing RC Pier by Polymer cement mortar for shotcrete with CFRP grid

Stress transfer mechanism of the reinforced interface and seismic retrofit existing RC Pier by Polymer cement mortar for shotcrete with CFRP grid

Intermediate Crack Debonding of Polymer Cement Mortar Overlay-Strengthened RC Beam

The bond behavior at the polymer cement mortar (PCM)-concrete interface particularly affects the structural behavior of overlay-strengthened slabs or beams, and the debonding of the PCM overlay was one of the major failure modes. The design procedure of PCM overlay to strengthen an RC element should avoid these premature debonding failures. Because no reliable design method for retrofitting with the PCM overlay is currently available for the practitioner, a need exists to understand the mechanism of the PCM overlay debonding process to prevent failure. This paper presents an analytical approach for a PCM overlay-strengthened beam failed by intermediate crack (IC) debonding. The limit of transferred shear force along the PCM-concrete interface to avoid any occurrence of debonding is analytically provided. The reliability and accuracy of the proposed analytical procedure have been successfully verified by knowing the ratio of analytical and experimental strength of the PCM-strengthened beams compiled in a bending test database, which has a mean value of 1.10 and a standard deviation of 0.14.