Addition Of Ethylene Vinyl Acetate Research Articles

Balancing the sustainable component of ethylene-vinyl acetate for achieved better compatibility improvement of wax-based warm mix additives in bitumen

The ethylene-vinyl acetate (EVA) polymers are always doped into waxy bitumen to inhibit network of wax crystals in bitumen. However, the compatibility improvement behaviors between wax-based warm mix (WWM) additives and bitumen by EVA are not clear, and the sustainable components of EVA for corresponding WWM additives to achieve better compatibility improvement are also not determined. This paper investigated compatibility improvement behaviors between commonly used WWM additives and bitumen after the addition of EVA to obtain sustainable components of EVA through experimental method of activation energy of viscous flow (AEVF) and density function theory-molecular dynamic (DFT-MD) calculations. The results show that the repulsions between the end of main-chain with highest electronegativity in WWM additives and polar molecules of EVA can alleviate the aggregation behaviors of WWM additives and EVA displays the best and worst compatibility improvements for additives with shortest and longest carbon chains, respectively. The dispersed asphaltenes combined with EVA can form the composite wax inhibitors (WIs) systems to increase diffusion coefficient and reduce percentage increment values of cohesive energy density (CED) to further disrupt ordered degree of WWM additives. On this basis, the sustainable carbon numbers of main-chain for EVA that are slightly less than average carbon numbers of WWM additives will help to better improve the compatibility of WWM additives. This investigation can provide the inspiration on how to choose the sustainable components of EVA to achieve high-efficiency compatibility improvement for corresponding warm mix asphalts (WMAs) with different average carbon numbers.

Experimental Investigation of LDPE and EVA on Asphalt Binder

Abstract: This research study aims to investigate the impact of incorporating Ethylene Vinyl Acetate (EVA) and Low-Density Polyethylene (LDPE) on the properties of asphalt binder. The use of polymer-modified asphalt binders has gained significant attention in recent years due to their potential to improve the performance and durability of asphalt pavements. EVA and LDPE are two commonly used polymers that have shown promise in enhancing the rheological and mechanical properties of asphalt binders. The experimental investigation involved the preparation of asphalt binder samples with varying percentages of EVA and LDPE, ranging from 0% to 8% by weight. A series of laboratory tests were conducted to evaluate the effects of polymer modification on the fundamental properties of asphalt binder. These tests included penetration, softening point, ductility, viscosity, and dynamic shear rheometer (DSR) tests.The results of the study indicated that the addition of EVA and LDPE led to notable improvements in the rheological and mechanical properties of asphalt binder. Increased polymer content resulted in reduced penetration values, higher softening points, and improved resistance to rutting and deformation. Additionally, the modified binders exhibited enhanced viscosity and elastic behavior, as indicated by the DSR tests. The study also investigated the compatibility between EVA/LDPE and asphalt binder through microscopy and chemical analysis techniques. The findings of this experimental investigation contribute to the understanding of the effects of EVA and LDPE on asphalt binder performance. The results highlight the potential of these polymers in enhancing the resistance to rutting and deformation of asphalt pavements. This research can serve as a basis for further studies on polymer modification of asphalt binders and aid in the development of improved asphalt pavement materials with enhanced durability and longevity.

Asphalt 60/70 Penetration Analysis of AC/BC Mixture With the Addition of Ethylene Vinyl Acetate (EVA) As Asphalt Raw Material

This study was conducted to determine how much influence EVA (Ethylene Vinyl Acetate) added to Laston AC-BC has on Marshall characteristic values. The Marshall test carried out will produce stability values at the optimum asphalt conditions that meet the 2018 Highways specifications. The stability value will be used to analyze changes in the characteristics of the Laston AC-BC (Asphalt Concrate – Binder Course) mixture after adding a mixture of EVA (Ethylene Vinyl Acetate) . To determine an aggregate gradation in the AC-BC mixed layer, coarse aggregate is used in the form of crushed stone with a maximum size of ” while for fine aggregate it is a mixture of crushed stone, stone ash and sand. The additive or modifier used is EVA (Ethylene Vinyl Acetate) polymer. Next, to obtain good asphalt concrete, the gradation of the aggregate must meet the general specifications of Bina Marga 2018 which have been determined through SNI-ASTM-C136-2012. In making the test object, ± 1200 gram of aggregate and asphalt are needed so that the specified height of the test object will be produced. Through the analysis of the aggregate sieve, the weight of the aggregate required for the test object can be calculated. Modification of asphalt with EVA aims to determine the stiffness and properties of asphalt in resisting loading with a certain penetration value so as to produce a Penetration Index value which will affect the characteristics of asphalt against weather changes. Research and knowledge related to the addition of a mixture of EVA (Ethylene Vinyl Acetate) to asphalt can be further developed so that it can be implemented on types of road pavements with higher traffic density conditions.

Effect of Hydrophilic Polyurethane on Interfacial Shear Strength of Pisha Sandstone Consolidation under Freeze-Thaw Cycles.

The W-OH type polyurethane (W-OH) has been proven to be an economical and environmentally friendly slope protection solution for slope maintenance in Pisha sandstone areas. However, the Pisha area belongs to a typical temperate continental climate with large diurnal temperature changes in winter, spring, and autumn and freezing and thawing occurring alternately between days and nights. Under freeze-thaw cycle conditions, the effect of slope treatment largely depends on the interface shear strength between W-OH-treated Pisha sandstone and pristine sandstone. Therefore, this paper studies the interfacial shear strength and long-term durability of Bisha sandstone consolidation (W-OH-treated Pisha sandstone) and Pisha sandstone under freeze-thaw cycles. First, the effects of different W-OH concentrations and different water contents on the freeze-thaw cycle interface were studied using a direct shear test. Based on the experimental results, the W-OH material was further modified with ethylene vinyl acetate (EVA). Finally, the damaged surface of the sample was observed through an ultra-depth-of-field microscope, and the damage mechanism of the interface caused by the freeze-thaw cycles was further discussed. The experimental results show that the peak shear strength at the interface increases with the increase in W-OH concentration and decreases with the increase in freeze-thaw cycles. The cohesion at the interface generally increases with the increase in W-OH concentration and reaches a maximum value of 43.6 kPa when the W-OH concentration is 10%. At the same time, under the condition of high water content, the curing of the W-OH material has no significant effect on the bonding performance of the interface. Using EVA to modify the W-OH material can improve the freeze-thaw durability of the interface. After modification, the interfacial cohesion of the sample increases with the increase in the EVA concentration and can reach 162% of the original. Using an ultra-depth-of-field microscope, it was found that the repeated solidification-melting action of water between the interfaces makes the consolidated body on the damaged surface fall off, resulting in cracks. As the water content between the interfaces increases, the damage to the material is greater. However, the addition of EVA can fill the uncovered pores of W-OH cement, thereby improving the cohesion at the interface and effectively alleviating the freeze-thaw damage caused by the high water content at the interface. The results of this study can provide some theoretical references for slope treatment in the Pisha sandstone area using W-OH materials.

Enhanced recyclability of waste plastics for waterproof cementitious composites with polymer-nanosilica hybrids

Waste plastics may be an environmentally friendly alternative to natural aggregates for concrete manufacture. However, the inferior bond strength between waste plastic aggregates and cement matrix greatly limits the uses of waste plastics for engineering designs and applications. Herein, ethylene–vinyl acetate (EVA) and nanosilica (nS) were jointly employed to enhance the matrix-aggregate interactions in cementitious composites with recycled waste plastics (RWPs). Waterproof properties of the cementitious composites with EVA and nS hybrids were measured. A non-destructive test using micro-focus X-ray computed tomography (µ-XCT) with contrast enhancing technique followed by microstructural tests (SEM/BSE and EDS) were conducted to in-situ trace liquid migration in the composite specimens. The single addition of EVA into the cementitious composites increased the porosity and depressed the compressive strength, but greatly decreased the water sorptivity by nearly 50 %. The organic–inorganic (EVA-nS) hybrids enhanced the recycling potential of the waste plastics in terms of the mitigated strength reduction and improved waterproofing performance. The coupled polymerization of EVA and nanofilling of nS effects were resolved to account for the recyclability improvement. The findings would shed light on design and fabrication of cementitious materials towards large scale recycling methods and technologies of waste plastics.

Research on improving polymer pervious concrete mechanical strength by adding EVA to UP resin binder material

Pervious concrete (PC) made of silicate cement has advantages including low cost, low contraction, and high permeability. However, its strength and durability are lower than those of conventional cement concrete. In recent years, the resin composite material is added to the binder material to effectively improve the mechanical properties and durability of permeable concrete. Commonly used resin composites include epoxy and unsaturated polyester (UP). These resin composites are thermosetting, which cure rapidly and feature high strength and durability. The high cost and viscosity of epoxy resin limits its applications. UP is preferable to epoxy due to its lower concentration and price. This study explored the mechanical performance of high-performance PC with UP resin as the binder. Concretes were fabricated with binders of 10%, 30%, and 40% UP resin content, and specimens were mixed with 5–10-mm gravel aggregate. Compression, flexural, and abrasion testing were conducted to determine the specimen durability. The results revealed that the PC with 30% UP resin had optimal performance. UP resin is composed of a straight chain, and although it has excellent rigidity, its ductility is poor. To address this problem, thermoplastic material ethylene–vinyl acetate (EVA) was incorporated into the binder at 10%, 15%, and 20% to improve the ductility. Compression, bending, and abrasion tests showed that the addition of EVA improved the ductility and durability of the samples. Comprehensive experimental results: UP resin was matched with thermoplastic materials; EVA could improve the mechanical properties of small walking bricks with UP resin as the binder material. Durability further promotes the feasibility of a new pavement construction method from the production of a single brick.

Beeswax–EVA/Activated-Charcoal-Based Fuels for Hybrid Rockets: Thermal and Ballistic Evaluation

Beeswax (C46H92O) is a naturally derived substance that has the potential to be used as a solid fuel for hybrid rocket applications and as a substitute for paraffin wax fuel in hybrid rockets. BW burns more efficiently than paraffin wax because of the oxygen molecule it contains. The low thermal stability and poor mechanical properties of BW limit its practical use for upper-stage propulsion applications, and these issues are rarely addressed in the literature on hybrid rockets. This study investigates the thermal stability and ballistic properties of BW using ethylene-vinyl acetate (EVA) and activated charcoal (AC) as an additive. The thermal stability of BW–EVA/AC fuel compositions was analyzed using a thermogravimetric analyzer (TGA). The thermal stability of the blended BW compositions improved significantly. A laboratory-scale hybrid rocket motor was used to evaluate such aspects of ballistic performance as regression rate, characteristic velocity, and combustion efficiency. The results revealed that the pure BW exhibited a higher regression rate of 26.5% at an oxidizer mass flux of 96.4 kg/m2-s compared to BW–EVA/AC blends. The addition of EVA and AC to BW was found to increase the experimental characteristic velocity and combustion efficiency. The combustion efficiency of BW-based fuel was improved from 62% to 94% when 20 wt.% EVA and 2 wt.% AC were added into the fuel matrix.

Optimize PLA/EVA Polymers Blend Compositional Coating for Next Generation Biodegradable Drug-Eluting Stents.

In this research work, polymer blends of poly-lactic acid (PLA)/ethylene vinyl acetate (EVA) were prepared as the drug carrier materials for a bi-layer drug-loaded coating film for coronary stents. Different optimum compositions of blends were prepared by using an intense mixer. Then, the blends were hot-pressed and later cold-pressed to prepare for films of different thickness. The changes in weight, surface analysis and biodegradability with increasing time were studied using Scanning electron microscopy (SEM), weight loss and biodegradability tests. The mechanical and thermal properties of drug-loaded films were studied through universal testing machine (UTM) and thermo-gravimetric analysis (TGA). The effects of PLA, EVA and drug contents on in-vitro drug contents were investigated through the Ultraviolet-Visible Spectroscopy (UV-VIS) chemical analysis technique. The results obtained clearly showed that the addition of PLA promoted the unleashing of the drug whereas the addition of EVA nearly did not have the same affect. The mechanical properties of these various films can be tuned by adjusting the contents of blend parts. The factors affecting the unleashing of the drug became a serious matter of concern in evaluating the performance of bio-resorbable drug eluting stents. As a result, today’s chemical blends may be useful drug carrier materials for drug-loaded tube coatings capable delivering purgative drug in an incredibly tunable and regulated manner.

Pengaruh Penggunaan Aspal Modifikasi Polimer Ethyl Vinyl Acetat (EVA) Terhadap Campuran Laston Asphalt Concrete Wearing Course (AC-WC)

Asphalt concrete (Laston) has a high level of flexibility so that the placement of such a layer directly above the wear layer (AC-WC) make this layer susceptible to damage is too high temperature and heavy traffic loads. In addition to these, as well as the damage is too high viscosity when asphalt mixing with aggregate due to the ineffectiveness of quality control in Asphalt Mixing Plant (AMP) so that the asphalt temperature is not controlled. This study is intended to take advantage of Ethylene Vinyl Acetate (EVA) as a polymer in a mixture of Asphalt Concrete – Wearing Course). Stages of materials testing carried out on three specimen to be used, ex Clereng aggregate, asphalt penetration pertamina 60/70, and modifier type of polymer Ethylene Vinyl Acetate (EVA). The test in laboratory with Marshall Test to acquire properties with a value of EVA modified aphalt content variation of 0% (Variation 1), 1% (Variation 2), 2% (Variation 3), 3% (Variation 4), and 4% (Variation 5). The result of Marshall Test showed that the addition variation 1 to variation 5 of EVA modified asphalt tend to increase Optimum Asphalt Content, stability value, and Marshall Quotient (MQ) value of AC-WC mixture. Generally, Asphalt Concrete-Wearing Course (AC-WC) mixtures with the addition of EVA modified asphalt gives the best result compared to AC-WC mixture without EVA modified asphalt

Improved Crack Resistance and Pore Structure of Cement-Based Materials by Adding EVA Powder

The improved properties of ethylene-vinyl acetate (EVA)-modified cement-based materials have not been fully clarified, especially crack resistance and pore structure. The purpose of this research was to investigate the influence of EVA copolymer on the mechanical performances and microstructural properties of cement paste. Strengths, autogenous and drying shrinkage, and water absorption expansion were investigated to evaluate the mechanical properties and volume stability. The ring restrained shrinkage and chloride permeability tests revealed the crack resistance and enhancement of impermeability. The microstructures of EVA-modified cement-based materials were characterized by scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) techniques. The experimental results indicated that mixing EVA into cement-based materials increased the flexural strength, reduced the crack propagation and chloride ion penetration, and reduced the negative capillary pressure by improving the water retention. The addition of EVA resulted the remarkable reduction of harmful pores. The optimal mass fraction of EVA powder was approximately 4%.

Thermoplastic Elastomer based on Recycled HDPE/Ground Tire Rubber Interfacially Modified with an Elastomer: Effect of Mixing Sequence and Elastomer Type/Content

ABSTRACT The effect of interfacial interaction and processing methods (one-step and two-step) on the structure–property relationships of ternary blends was investigated. The addition of ethylene-vinyl acetate (EVA) and ethylene octene copolymer (POE) resulted in homogeneous structure and greatly improved rubber-like properties of recycled high-density polyethylene (rHDPE) and regenerated tire rubber (RR) blends. Interfacial tension calculations revealed a high tendency of POE to encapsulate rubber particles (complete wetting). The two-step processing contributed to perfect encapsulation of the rubber phase via a soft/thick POE interface resulting in uniform RR particle dispersion, high elongation at break (138.5%), and impact strength (394 J/m) of rHDPE/(RR/POE) (20/80) ternary blend.

PERFORMANCE EVALUATION OF ETHYLENE-VINYL ACETATE MODIFIED BITUMEN AND MIXTURES

Interconnectivity necessitates the use of transportation facilities and infrastructure. All highway design agencies seek acceptable, long-lasting, and cost-effective strategies while designing these facilities. The traffic demands on roads are much higher than they have been in the past. Increased traffic loads, larger traffic volumes, and insufficient maintenance have all contributed to serious road surface distress (e.g., rutting and cracking) due to rapid development. As conventional asphalt combinations are unable to withstand high axle loads and tire pressures, interest in polymer-modified asphalt has grown. Polymer modification of asphalt is one of the most effective ways to improve asphalt qualities. The practical temperature range of binders is greatly expanded by polymers. The inclusion of the polymer can considerably improve the binder qualities by increasing the stiffness of the bitumen and enhancing its temperature susceptibility, enabling the building of safer roads and lower maintenance costs. This research presents a laboratory investigation of the Ethylene Vinyl Acetate (EVA) polymer-modified bitumen. NHA-B gradation, PARCO 60/70 grade bitumen, and EVA polymer of TPI Polene Public Company Limited were used. Penetration, softening point, ductility, and viscosity tests were used to evaluate the conventional properties of the asphalt binders. Three different percentages of polymers were used i.e., 2%, 4%, and 6%. The impact of the EVA polymer on permanent deformation and moisture susceptibility was investigated. A double wheel tracker (DWT) was used to quantify permanent deformation (rutting), and a Universal Testing Machine (UTM) was used to examine moisture susceptibility using an Indirect Tensile Strength (ITS) test. For different percentages of bitumen volumetric properties according to Marshall Mix Design procedure were measured, and then Optimum Bitumen Content (OBC) was evaluated. Performance tests were performed using above mentioned percentages of EVA. The rutting potential of mixes was improved by the addition of EVA as compared to control asphalt mixes. The same effect of the polymer was on the moisture susceptibility of the prepared samples. This showed that EVA polymer can be used in flexible pavements to reduce permanent deformation and high-temperature problems.

Effects of temperature and humidity on properties of ethylene/vinyl acetate‐modified ternary complex mortar

AbstractThe ternary complex system of Portland cement, aluminate cement, gypsum is suitable for the repair and strengthening of concrete structures due to its excellent characteristics, such as fast hardening, early strength, micro‐expansion, and so on. However, the application of this ternary complex was limited by the problems of low toughness and strength degradation in the late curing period. Therefore, it is meaningful to study the effects of different curing conditions on repairing materials in concrete engineering. In this paper, the actual repair environment was simulated, and the effects of different curing temperature and humidity on performances of ethylene/vinyl acetate (EVA) modified ternary complex were researched. The initial and final setting time of ternary complex increases with the increase of EVA content. And under different curing temperature and humidity, the addition of EVA improved the toughness of the ternary complex and reduced the water absorption, EVA can effectively prevent the late strength decrease of ternary complex caused by high curing temperature. Under the curing conditions of 40 and 60°C, the addition of EVA greatly improved the flexural strength and toughness of the ternary complex, low temperature environment is not suitable for EVA‐modified ternary complex.

Thermal stability and kinetic study of blended Beeswax-ethylene vinyl acetate based hybrid rocket fuels

Hybrid rocket fuels are safer and have unique operational and handling features compared to conventional rocket fuels. Here, an attempt to improve the thermal stability and combustion performance of blended fuel Beeswax with Ethylene Vinyl Acetate (EVA) and activated charcoal has been tried. The weight percentage of EVA was varied from 10 to 20% in the formulation and the activated charcoal by 1 to 2%. Thermal stability characteristics of Beeswax-EVA based fuel samples were studied through TG/DTG/DSC experiments and the kinetic analysis. TG analysis reveals that the addition of EVA (10% to 20%) gives a good improvement in thermal stability. The TG-DTG results an enhancement in the combustion parameter's values and DSC analysis reveals that the addition of EVA improves the combustion enthalpy. The addition of EVA and activated charcoal decreases the activation energy by 29.5-65.3% providing ease in burning with the lower required energy for reactants.

Waste tyres crumb rubber as a sustainability enhancer for polymer-modified and hybrid polymer-modified bitumen

ABSTRACT The increasing amount of waste vehicle tyres has already proved to be hard to dispose of properly and lead to environmental problems, such as soil contamination and toxic blazes. This study aimed to use recycled tyre rubber material (crumb rubber - CR) and combine it with well-known polymers in road engineering, such as styrene–butadiene-styrene (SBS) and/or a combination of SBS and ethylene-vinyl acetate (EVA) to develop hybrid recycled polymer modified bitumen (PMB). Most of the times, CR is only added to neat bitumen at high contents to enhance its properties despite some drawbacks. Physical, chemical, thermal and rheological tests were conducted to evaluate the overall performance of the blends with and without the addition of stabilising agents. CR has shown to increase the viscosity of the bitumen. The addition of EVA into CR/SBS blends has simultaneously improved the rheological properties specifically at intermediate and high temperatures. To conclude, the utilisation of small percentages of recycled tyres in PMBs and hybrid PMBs did not negatively affect the satisfactory performance of SBS-modified bitumen. This consequently encourages greater usage of CR which also mitigates the waste disposal problem at landfills.

Influence of ethylene-vinyl acetate on the performance improvements of low-density polyethylene-modified bitumen

Due to the low recyclability and slow degradation in nature, waste polyethylene (PE) represents a negative effect on the environment and its disposal is discordant with the idea of sustainable development in general. On the other hand, the application of the polymer-modified bitumen is an economical and efficient alternative for improving the performance of asphalt pavements. However, the thermal storage stability of PE-modified bitumen is the main factor that prevents its wider application. The main objective of this research was to investigate the feasibility and to quantify the effect of the addition of ethylene-vinyl acetate (EVA) on PE-modified bitumen. This was achieved by testing the modified bitumen produced with the single mass fraction of PE of 4% and different mass fractions of EVA in the range from 2 to 8%. The experimental program included penetration, softening, ductility, rheological properties in high-and low-temperature range, thermal storage stability and compatibility of phases, environmental scanning electron microscopy, and Fourier transform infrared spectroscopy. The results indicated that the addition of EVA increased the viscosity, complex shear modulus, as well as the elasticity of bitumen. Although the high-temperature behaviour was improved, the behaviour in the low temperature range was practically unaffected. The storage stability and segregation of phases were positively affected to a remarkable extent. The base bitumen and PE interacted only physically, but some particular chemical interaction took place with the addition of EVA.

Bending Behavior of Ethylene Vinyl Acetate Modified Engineered Cementitious Composite under Drop Weight Impact Testing

In this study, a drop weight testing method was employed to investigate the impact bending behavior of ethylene vinyl acetate (EVA) modified engineered cementitious composite (ECC). The ECC with no EVA was selected as control, and the static and impact bending behavior was compared with the EVA modified ECC. The results showed that the compressive strength of EVA modified ECC decreased by 20%~30% in comparison with control ECC with fly ash substitution ratio variation. The addition of EVA can improve the bending toughness of ECC dramatically under static loading condition. As different from the static bending, the impact bending toughness of EVA modified ECC was smaller than that of control under impact loading condition. However, the degree of damage of EVA modified ECC was lower than control due to small crack width.

POM/EVA Blends with Future Utility in Fused Deposition Modeling.

Polyoxymethylene (POM) is one of the most popular thermoplastic polymers used in the industry. Therefore, the interest in its potential applications in rapid prototyping is understandable. Nevertheless, its low dimensional stability causes the warping of 3D prints, limiting its applications. This research aimed to evaluate the effects of POM modification with ethylene-vinyl acetate (EVA) (2.5, 5.0, and 7.5 wt.%) on its processing (by melt flow index), structure (by X-ray microcomputed tomography), and properties (by static tensile tests, surface resistance, contact angle measurements, differential scanning calorimetry, and thermogravimetric analysis), as well as very rarely analyzed emissions of volatile organic compounds (VOCs) (by headspace analysis). Performed modifications decreased stiffness and strength of the material, simultaneously enhancing its ductility, which simultaneously increased the toughness even by more than 50% for 7.5 wt.% EVA loading. Such an effect was related to an improved linear flow rate resulting in a lack of defects inside the samples. The decrease of the melting temperature and the slight increase of thermal stability after the addition of EVA broadened the processing window for 3D printing. The 3D printing trials on two different printers showed that the addition of EVA copolymer increased the possibility of a successful print without defects, giving space for further development.

Weathering characteristics of wood-plastic composites compatibilized with ethylene vinyl acetate

Poplar wood flour wood-plastic composites (WPCs) prepared with high-density polyethylene and modified with different amounts of ethylene vinyl acetate (EVA) were created. The influence of EVA content on the surface properties and weathering characteristics after ultraviolet (UV) treatment was investigated. The results showed that WPCs treated with EVA had improved thermal stability, and the surface polarity was reduced. The addition of EVA slowed the fading of the WPCs, and the color difference was the smallest when the EVA content was 5%. Both the bending strength and the modulus of elasticity (MOE) of the WPCs decreased after the UV treatment. However, when the EVA content was 5%, the bending strength retention ratio and MOE retention ratio were greatest. Scanning electron microscopy showed that the addition of EVA reduced the amount of pores and gaps on the fractured surfaces of the WPCs. The comprehensive performance of the WPC anti-weathering properties was greatest when the EVA level was 5%.

Influences of EVA and methylcellulose on mechanical properties of Portland cement-calcium aluminate cement-gypsum ternary repair mortar

Portland cement–calcium aluminate cement–gypsum ternary repair mortar has the problems of poor toughness, low flexural strength and later strength retrogression in the process of road repair. The effects of ethylene-vinyl acetate (EVA) copolymer and methylcellulose on the mechanical properties of Portland cement–calcium aluminate cement–gypsum ternary repair mortar were investigated. The flexural strength of mortar increases with increasing content of EVA powder by less than 1.5% and the modified mortar with 1.5% EVA has better toughness but the late strength did not grow or was even lower than early strength. The combination of EVA and methylcellulose can effectively improve the flexural and compressive strengths and ensure the development of late strength. The acetic group of EVA copolymer consumes calcium hydroxide to produce calcium acetate under the basic condition, thus forming fine ettringite (AFt) crystal, which can improve the flexural strength with the filling effect of EVA particles. The methylcellulose has good water retention ability, which improves the stability of AFt and thus ensures the late strength. The combined addition of EVA and methylcellulose into the ternary system can improve the stability of AFt, optimize the crystal morphology of AFt, and increase the compressive strength and flexural strength, so as to ensure the development of strength in the later stage.