Polymer Cement Mortar Research Articles

Redispersible Acrylic Ester Polymers: Effect of Polymer Property Changes Due to Polymerization Method Modification and Functional Additives on the Performance of Polymer Cement Mortar

This paper presents an experimental study aimed at improving the performance of polymer cement mortar by evaluating the properties of acrylic ester redispersible polymers, synthesized using a change in polymerization method from emulsion monomer to monomer dropwise addition methods, along with the use of a functional additive in the form of a foaming agent. To achieve the research objectives, a polymer with a glass transition temperature of −11 °C was synthesized by fixing the monomer ratio, particle-size distribution, and glass transition temperature, and the physical properties of the polymer cement mortar were assessed. The results showed that polymers synthesized using the modified polymerization method increased elongation at break and possessed a 35% smaller average particle size. The use of the foaming agent also resulted in enhanced tensile strength. The polymer cement mortars made with these respective polymers demonstrated improvements in compressive strength 11~25%, flexural strength 53~77%, bond strength 78~113%, volumetric changes 65~88%, and water absorption 30~70%. These findings suggest that changes in the polymerization method and the incorporation of functional additives influence the average particle size and air entrainment control properties of the polymers, thereby positively impacting the performance of the cement hydrates.

Study on Flexural Performance of Reinforced Concrete Beams Strengthened with FRP Grid–PCM Composite Reinforcement

To study the flexural performance of fiber-reinforced polymer (FRP) grid–polymer cement mortar (PCM)-composite-strengthened RC beams, the finite element numerical simulation of FRP grid–PCM composite RC beams is carried out using ABAQUS to analyze the effects of the amount of FRP grid reinforcement, the type of FRP grid material, and the geometry of FRP grid on the flexural performance of reinforced concrete beams and to establish the flexural capacity calculation formula of FRP grid–PCM-reinforced RC beams in case of debonding failure, based on analysis of the influencing factors. The results show that increasing the reinforcement of the FRP grid and increasing the stiffness of the FRP grid can improve the flexural bearing capacity of RC beams, and the change of FRP grid geometry has little effect on the flexural bearing capacity of RC beams. The established formula for calculating the flexural bearing capacity of FRP grid-reinforced concrete beams can better predict the flexural capacity of reinforced concrete beams under peeling failure.

The research progress and Hotspot analysis of polymer cement mortar based on bibliometrics

Ordinary cement mortar is commonly used in building engineering due to its high strength, affordability, and easy access to raw materials. However, it suffers from high shrinkage and poor impermeability, which result in reduced building service life and significant carbon dioxide emissions during production. Polymer additives have been found to enhance the mechanical properties of cement mortar, leading to increased interest in polymer cement mortar by researchers. This study collected and analyzed 420 papers published between 1995 and 2023 in the field of polymer cement mortar. The analysis included publication trends, author cooperation networks, national cooperation networks, published journals, co-citation of references, and keywords. The findings reveal a rapid publication growth from 2018 to 2023, with China making the most significant contribution in this field. Among the scholars, Ru Wang has published the highest number of articles in the field of polymer cement mortar, while Ohama’s papers have been cited the most. The journal with the most articles is Construction and Building Materials. Research in polymer cement mortar focuses on mechanical properties, performance, hydration process, microstructure, and other related aspects. The reinforcement effect of polymer-modified cement mortar on reinforced concrete and applying superabsorbent polymer-modified cement mortar and polymer fiber in cement mortar have emerged as recent research frontiers. This study can help scholars quickly identify high-quality references and research frontiers in the field of polymer cement mortar while also providing research directions and ideas.

Study on the influence of wedge-shaped steel plate hoops and steel strands wire mesh-PCM on seismic performance of damaged RC columns

This paper presents an experimental investigation on the use of polymer cement mortar (PCM) and steel strands wire mesh (SSWM) for strengthening damaged reinforced concrete (RC) columns. A new type of anchor device, wedge-shaped steel plate hoops (WSSPHs), was developed to maximize the resistance of the steel strands. The study aimed to analyze the impact of spacing and prestressing level on the mechanical properties of the damaged RC columns. Six columns were constructed and tested under low-cycle reciprocating quasi-static tests, including three control columns and three strengthened columns. The research focuses on the strengthening mechanism of WSSPHs and explores the influence of steel strand prestressing level and spacing on factors such as failure modes, hysteresis behavior, stiffness degradation, and cumulative energy dissipation of the strengthened columns. The test results showed that while the strength and stiffness of the strengthened specimens were not fully restored due to significant damage, the ductility and energy dissipation of the columns were improved. Moreover, columns with higher steel strand prestressing levels and narrower spacing demonstrated better strengthening effects. The study assessed the level of damage in specimens using the Park-Ang model, confirming the effectiveness of the proposed strengthening method.

Numerical analysis of reinforced concrete beams enhanced in shear with external polymer cement mortar‐bonded FRP grid

AbstractThis paper presents a finite element (FE) modeling approach to assess the performance of reinforced concrete (RC) beams strengthened in shear using external polymer cement mortar (PCM)‐bonded basalt fiber‐reinforced polymer (BFRP) grids. The study begins with an experimental program and FE modeling of a double shear bond test, simulating the bond behavior between the BFRP grid and RC beams with PCM. Subsequently, a FE model for BFRP shear‐strengthened beams explores key parameters, including shear span to depth ratio, bonding agent type (PCM and epoxy resin), and angles between BFRP grid bars and the beam axis. Comparative analysis with experimental results verifies the accuracy of the FE models. Additionally, a critical parameter, the BFRP reinforcement ratio, is numerically investigated, revealing that achieving a ratio between 1.33% and 1.55% enhances both maximum load and deflection in beams strengthened with externally bonded composite reinforced mortar.

Improving bonding performance of PCM-concrete interface under elevated temperatures by using different adhesives

Polymer cement mortar (PCM) has been widely utilized in engineering practice for the repair and strengthening of damaged concrete. However, the bond strength of PCM-concrete interface can deteriorate under high temperatures. To enhance bonding performance, a new interface treatment method needs to be explored. This study aimed to investigate the bond performance between concrete and PCM after adding a layer of epoxy bonding agent (EP) or carbon fiber-reinforced polymer (CFRP) to the interface, as well as to investigate the effect of temperature. The bond behavior was evaluated by interfacial split tensile tests. The experimental results show that the splitting tensile strength of the specimens decreased as the temperature increased. After being exposed to a temperature of 100 °C, the splitting tensile strength of specimens without interface reinforcement, EP- and CFRP-reinforced interface specimens decreased by 35.42%, 58.90%, and 63.39%, respectively. When the ambient temperature exceeds 80 °C, bonding with epoxy or CFRP does not improve the bond performance due to the decomposition of epoxy. Finally, the relationship between the splitting tensile strength of the three types of specimens and temperature was clarified, and a model was developed to predict the strength degradation under elevated temperatures. The results are useful for improving the durability and safety of concrete structures repaired with PCM.

Information fusion-based maintenance strategies selection for coastal concrete bridges using recycled fishing nets

Repurposing recycled materials for coastal concrete bridge maintenance addresses both engineering requirements and marine ecosystem preservation. This study explored the application of recycled nylon (RN) and polyethylene (PE) from discarded fishing nets in coastal concrete beam maintenance. Specifically, these fibers were incorporated into the polymer cement mortar (PCM) to produce two repair materials. Then, thirteen unrepaired or preventive/post-repaired concrete beams were exposed to the tidal zone for one or two years, followed by beam bending tests and the establishment of the corresponding parametric Finite element modeling (FEM). As an alternative to traditional heavy-parameter models, a novel lightweight crack segmentation model (LiteSqueezeSeg) was proposed for quantitatively analyzing beam surface crack properties. Lastly, experimental, simulated, and quantitative crack information were fused to comprehensively assess the beam performance. Results showed that both PCM-RN and PCM-PE effectively inhibit chloride ion penetration. The proposed LiteSqueezeSeg model (95.66% accuracy) achieved nearly identical performance to Deeplab v3 + but only with about 1/6 parameters. Fused results revealed that PCM-PE repaired beams exhibited superior mechanical performance but inferior ductility compared to PCM-RN. Moreover, both PCM-PE and PCM-RN repaired beams demonstrated that preventive repairs achieved more balanced performance than post repairs. Consequently, utilizing PCM-RN for preventive repair emerged as an optimal candidate. This study significantly contributes to the utilization of waste fishing nets in coastal concrete structure maintenance.

Polymer cement mortar strengthened RC beams with/without silica fume as repair material

Polymer cement mortar (PCM) overlaying methods leads to brittle interfacial debonding before its classical failure causing a sudden decrease of the load-carrying capacity. For a reliable design procedure for the practitioner, a need exits to prevent the interfacial debonding. The proposed modified 5 % silica fume (M) PCM overlay is intended to delay debonding because it increased the concrete-PCM bond (confirmed in our previous study). Fourteen RC beams (size-150x150x1440 mm, a/d – 3.5) using C40 concrete (mix proportion – 1:2.1:2.6) were prepared and strengthened with rebar (2D6 and 2D10), CFRP grid with changing stiffness (low, medium and high), and CFRP strand sheet (50 mm and 150 mm width) as strengthening reinforcement that embedded with normal (N) PCM and MPCM overlay of thickness 20 mm to investigate the effectiveness of silica fume. Four-point bending test were made at room temperature to evaluate the flexural performance. Compared to NPCM, MPCM with all cases of strengthening reinforcement enhanced the crack numbers, ductile behavior, peak load (12–25 %) and debonding load (3–33 %), proving MPCM as ideal cementitious matrix for strengthening. The flexural strengthening configuration using MPCM and reinforcement amount (area x tensile strength) ratio of 0.5 between strengthening and main bar proved to be more efficient as this configuration delayed the debonding failure, shifted fracture to classical mode and confirmed uniform shear stress transfer at the overlay-concrete interface. Conclusively, MPCM overlay nearly achieved a full-strength composite action which is effective to prevent the debonding that benefits practitioners.

Fabrication of graphene oxide/fiber reinforced polymer cement mortar with remarkable repair and bonding properties

Fabrication of graphene oxide/fiber reinforced polymer cement mortar with remarkable repair and bonding properties

Durability Enhancement Effect of Silica Fume on the Bond Behavior of Concrete-PCM Composites under Environmental Conditions.

The long-term performance of the concrete-polymer cement mortar (PCM) interface under environmental exposure is crucial to the safety of the PCM overlaying method as the environmental exposure of the repaired structures caused further degradation of the interface, leading to a significant reduction in intended service life. This study investigates the durability enhancement effect of silica fume of the concrete-PCM interface, considering an individual action of elevated temperature (e.g., 60 °C) [constant (short and moderate duration) and cyclic conditions] and moisture content [continuous immersion and wetting/drying (W/D) cycle]. Our previous research confirmed that the use of silica fume forms more C-S-H with strong binding force and enhances the interfacial bonding strength due to the denser microstructure at the interface, and it is expected to be utilized for durability purposes under the aforementioned exposure conditions. Under all elevated temperature exposure conditions, the reduction percentage of the interfacial performance corresponding to the respective reference specimens reduced significantly with the inclusion of silica fume with overlay material. The occurrence of interface fracture at lower load and a greater number of pure interface fracture modes observed in normal PCM specimens compared to modified PCM specimens indicates a positive influence of higher adhesion with better durability of modified PCM overlay with substrate concrete. Under both conditions of moisture content, significant reduction in interfacial strength was observed in normal PCM specimens. In all cases, the reducing ratio of interfacial strength was higher in normal PCM compared to modified PCM, indicating a positive influence of silica fume under moisture content. Furthermore, silica fume inclusion shifts the fracture mode from pure interfacial fracture to composite fracture mode, indicating a positive response of silica fume to improve the resistance of interface fracture under moisture content. Conclusively, the use of silica fume improves concrete-overlay layer adhesion and enhances the bonding durability under environmental exposure.

Crack Spacing-Based Flexural Capacity of Polymer Cement Mortar Overlay Reinforced Concrete Beams at High Environmental Temperature

Crack Spacing-Based Flexural Capacity of Polymer Cement Mortar Overlay Reinforced Concrete Beams at High Environmental Temperature

Study on Carbonation Resistance of Polymer-Modified Sulphoaluminate Cement-Based Materials

The use of tricyclic copolymer latex (AMPS) can effectively improve the carbonation resistance of sulphoaluminate cement. This paper investigated polymer AMPS and polycarboxylic acid to modify sulphoaluminate cement materials by exploring the carbonation level of sulphoaluminate cement paste and mortar and the strength before and after carbonation. Then, the optimal dosage of polymer and polycarboxylic acid was obtained so that the carbonation resistance of sulphoaluminate cement reached the best state. The compressive strength was significantly improved by adding AMPS for sulphoaluminate cement paste and mortar. After carbonation, the strength decreased and combined with the carbonation level; it was concluded that the carbonation resistance of sulphoaluminate cement materials was the best when the optimal dosage of AMPS and polycarboxylic acid was 5% and 1.8%, respectively. Due to the addition of AMPS, the hydrated calcium aluminosilicate (C-A-S-H) and hydrated calcium silicate (C-S-H) gels, generated by the hydration of sulphoaluminate cement and the surface of unreacted cement particles, are wrapped by AMPS particles. The water is discharged through cement hydration. The polymer particles on the surface of the hydration product merge into a continuous film, which binds the cement hydration product together to form an overall network structure, penetrating the entire cement hydration phase and forming a polymer cement mortar with excellent structural sealing performance. To prevent the entry of CO2 and achieve the effect of anti-carbonation, adding polycarboxylic acid mainly improves the sample's internal density to achieve the anti-carbonation purpose.

The Mechanism of Anticorrosion Performance and Mechanical Property Differences between Seawater Sea-Sand and Freshwater River-Sand Ultra-High-Performance Polymer Cement Mortar (UHPC).

There are abundant sea-sand resources on the earth. Traditional sea-sand concrete faced various problems relating to insufficient anticorrosion ability. In this paper, artificial seawater, sea sand, industrial waste, steel fiber, and polycarboxylate superplasticizer were used to prepare ultra-high-performance polymer cement mortar (SSUHPC). At the same time, freshwater river-sand ultra-high-performance polymer cement mortar (FRUHPC) with the same mixing ratio was prepared for comparative study. The compressive strength of SSUHPC reached 162.1 MPa, while the that of FRUHPC reached 173.3 MPa, which was slightly higher. Meanwhile, SSUHPC showed excellent anticorrosion characteristics in terms of carbonization, frost resistance and chloride resistance, and especially for sulfate resistance. The composition of SSUHPC was separated into three parts: mortar, pore and steel fiber, and the performance difference mechanisms of SSUHPC and FRUHPC were investigated by X-ray computed tomography (X-CT), mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The hydration degree of mortar in SSUHPC was higher, with higher content of CSH and CH, and its better optimized gel pore characteristics gave SSUHPC better corrosion resistance. The mechanical properties of SSUHPC were slightly poor due to the uneven dispersion of steel fibers and air pores, with an- air pore porosity of 1.52% (above 200 μm) that was twice that of FRUHPC (0.6%). In this paper, the mechanics and anticorrosion performance of ultra-high-performance polymer cement mortar prepared with seawater sea sand were comprehensively evaluated, and the mechanism of performance difference between SSUHPC and FRUHPC was revealed, conducive to the targeted improvement of sea sand concrete.

The effect of polymer-cement mortars with additives of aluminosilicate microspheres on the reservoir properties of exploration and production wells

The article shows that the use of lightweight grouting solution with hollow aluminosilicate microspheres can reduce the time and the cost of materials spent on securing exploration wells, ensure the rise of solution to the design height. Improved strength and fracturing of the stone ensures resistance to fracture during perforation, and a sufficiently strong bond can ensure tightness of the annulus in exploration and production wells.

Sulphate Corrosion Mechanism of Ultra-High-Performance Concrete (UHPC) Prepared with Seawater and Sea Sand.

The lack of river sand is becoming increasingly serious. In this study, we consider how to use sea sand to prepare innovative construction and building materials with excellent mechanical and durability properties. Sulphate corrosion causes expansion, cracking and spalling of concrete, resulting in the reduction or even loss of concrete strength and cementation force. In this paper, artificial seawater, sea sand, industrial waste, steel fiber and polycarboxylate superplasticizer were used to prepare ultra-high-performance polymer cement mortar (SSUHPC), and the sulphate corrosion mechanism was investigated. The strength and cementation force of mortar on the SSUHPC surface decreased and flaked off with the development of sulphate erosion, and the steel fiber rusted and fell off. A 3D model was established based on X-ray computed tomography (X-CT), and the results showed that SSUHPC maintained excellent internal structural characteristics despite severe sulphate erosion on the surface. Mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were adopted to investigate the sulphate corrosion mechanism of SSUHPC. We found a transition zone within 1–5 mm of the surface of SSUHPC. The Vickers hardness of mortar in this area was increased by 5~15%, and the porosity was reduced to 3.8489%. Obvious structural damage did not occur in this area, but a high content of gypsum appeared. UHPC prepared with seawater sea sand was found to have better sulphate resistance than that prepared with freshwater river sand, which supports the development and utilization of sea sand in concrete.

Studying the Influence of Silica Fume on Bond Strength of the PCM-Concrete Interface under Shear Stress Condition.

The polymer cement mortar (PCM) overlay method is a promising solution for strengthening deteriorated concrete structures in which the occurrence of premature debonding at the interfaces prevents the strengthened structures from achieving full serviceability. The purpose of this study is to improve the concrete–PCM interfacial bond to prevent premature debonding. There are two main focuses of this study: (i) investigation of the effectiveness of adding 5% silica fume to PCM in forming a chemical connection between concrete and PCM, based on a direct single-surface shear test using two roughness levels of concrete (smooth and rough) and microstructure analysis and (ii) performance evaluation of the bond between substrate concrete and a PCM overlay with/without silica fume at early ages and with different moisture conditions at the interface, based on a bi-surface shear test using rough substrate concrete surface. The inclusion of 5% silica fume with PCM caused an improvement in the interfacial strength (approximately 113% relative to the normal PCM in cases of without primer), with a smooth concrete substrate surface where mechanical bonding had less influence. In addition, lower Ca/Si values in the interface of modified 5% silica PCM specimens compared to the normal PCM specimens quantified by energy-dispersive X-ray spectroscopy (EDS) indicate the formation of a chemical connection at the concrete–PCM interface by transforming harmful Ca(OH)2 into more C-S-H which strongly improves the bonding strength. As a repair layer mortar, the positive influence of silica fume in modified 5% silica PCM specimens was also found at early ages and with different moisture conditions at the interface compared to the normal PCM. In conclusion, the addition of silica fume to the PCM caused chemical connection at the concrete–PCM interface and improved the interfacial performance.

Study of the Interfacial Bond Behavior between CFRP Grid-PCM Reinforcing Layer and Concrete via a Simplified Mechanical Model.

This paper presents the results of pull-out tests conducted to investigate the interfacial bond behavior between a carbon-fiber-reinforced polymer (CFRP) grid–polymer cement mortar (PCM) reinforcing layer and existing concrete, and proposes a simplified mechanical model to further study the interface bond mechanism. Four specimens composed of a CFRP grid, PCM, and concrete were tested. The influence of the type of CFRP grid and the grid interval on the interface bond behavior was discussed. The failure patterns, maximum tensile loads, and CFRP grid strains were obtained. The change process of interface bond stress was investigated based on the grid strain analysis. In addition, the simplified mechanical model and finite element model (FEM) were emphatically established, and the adaptability of the simplified mechanical model was validated through the comparative analysis between the FEM results and the test results. The research results indicate that a CFRP grid with a larger cross-sectional area and smaller grid interval could effectively improve the interface bond behavior. The tensile stress was gradually transferred from the loaded edge to the free edge in the CFRP grid. The interface bond behavior was mainly dependent on the anchorage action of the CFRP grid in the PCM, and the bond action between the PCM and the concrete. The FEM results were consistent with the test results, and the simplified mechanical model with nonlinear springs could well describe the interface bond mechanism between the CFRP grid–PCM reinforcing layer and concrete.

Experimental study on shear performance of improved high-performance polymer cement mortar–glass fiber reinforced plastic reinforced masonry wall

The improved high-performance polymer cement mortar (PCM) and glass fiber reinforced plastic (GFRP) system reinforcement was used in the research to strengthen and repair the masonry structure, so as to improve its bond stress, anchoring force, and integral performance without changing the original structure and further study the shear performance of masonry structure strengthened by the combination of the two. The optimum ratio of improved high-performance PCM was determined by analyzing the bend-press ratio of PCM test block. Improved high-performance PCM and GFRP were combined to strengthen the damaged masonry wall, and a five-piece masonry wall composed of “improved high-performance PCM+ with or without GFRP+ different original wall failure modes before reinforcement” was designed. Through diagonal loading shear test, the shear strength, vertical displacement, horizontal relative displacement, and failure models of masonry walls were obtained, and the effects of five different reinforcement methods and different materials on shear strength, stiffness, ductility, and failure modes of masonry walls were studied. The results show that compared with the unreinforced original wall, the shear strength of the masonry wall reinforced with the improved O4PCM is 43.5% higher, and its stiffness is also greatly improved, but the failure mode is still brittle failure; the shear strength of masonry walls strengthened by O4PCM and GFRP is 6.5% higher than that of masonry walls strengthened by O4PCM alone, and the stiffness is also increased. Its failure mode changes from brittle failure to ductile failure; with a failure mode of ductile failure, the shear strength of masonry walls strengthened by P4PCM and GFRP and that strengthened by P6PCM and GFRP are 4.8% and 12.7% higher than that strengthened by O4PCM and GFRP, respectively, and the stiffness is also increased compared with that strengthened by O4PCM and GFRP. After experimental comparison, it is the best scheme to strengthen masonry wall with improved P6PCM and GFRP.

Study on the Reinforcing Effects of the FRP-PCM Method on Tunnel Linings for Dynamic Strengthening

In recent years, fiber-reinforced plastic (FRP) has been widely used in the reinforcement of concrete structure fields due to its favorable properties such as high strength, low weight, easy handling and application, and immunity to corrosion, and the reinforcing effects with FRP grids on tunnel linings should be quantitatively evaluated when the tunnels encounter an earthquake. The aim of the present study is to estimate the reinforcing effects of fiber-reinforced plastic (FRP) grids embedded in Polymer Cement Mortar (PCM) shotcrete (FRP-PCM method) on tunnel linings under the dynamic load. A series of numerical simulations were performed to analyze the reinforcing effects of FRP-PCM method quantitatively, taking into account the impacts of tunnel construction method and cavity location. The results showed that the failure region on lining concrete is improved obviously when the type CII ground is encountered, regardless the influences of construction method and cavity location. With the increment of ground class from CII to DII, the axial stress reduction rate R σ increases from 13.18% to 48.60% for tunnels constructed by the NATM, while for those tunnels constructed by the NATM, R σ merely varies from 0.72% to 2.11%. R σ decreases from 43.35% to 34.80% when a cavity exists on the shoulder of lining, while decreasing from 14.7% to 0.12% when a cavity exists on the crown of lining concrete. All those conclusions could provide valuable guidance for the reinforcing of underground structures.

Study on Reinforcing Effects of FRP-PCM Method under Seismic Load

The aim of the present study is to estimate the reinforcing effects of fiber reinforced plastic (FRP) grids embedded in polymer cement mortar (PCM) shotcrete (FRP-PCM method) on tunnel linings, under the seismic load. Direct shear test was conducted to investigate the mechanical properties of bonding surfaces between the PCM concrete and concrete specimens sandwiched by a FRP layer. Numerical modelling was performed to analyze the reinforcing effects of FRP-PCM method quantitively, taking into accounts the influences of cavity position and construction method of tunnels, which could provide valuable guidance for the reinforcing of underground structures.