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1
Cai, Yong, Pei Ming Wang, and Shi Yun Zhong. "Influence of Coagulation of Polymer Dispersion on the Properties of Polymer-Modified Mortar." Advanced Materials Research 1129 (November 2015): 162–68. http://dx.doi.org/10.4028/www.scientific.net/amr.1129.162.
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The coagulation process of polymer dispersion in cement-based materials is different from that of the pure polymer dispersion during drying and film formation. This process is influenced by the various ions released from cement hydration and the interaction between polymer and cement grain in the water. This paper focuses on the coagulation of polymer dispersion during cement hydrating and the influence on the performances e.g. water absorption, flexural and compressive strength and bonding strength of cement mortar. Commercial anionic styrene-acrylate polymer dispersion was investigated in the coagulation process in the polymer-modified cement paste with polymer to cement ratio (p/c) from 5% to 20% and water to cement ratio of 0.3. The amount of coagulated polymer particles was measured by testing the solid content of the supernatant of the diluted polymer-modified cement paste for a period of time. The calorimetric property was measured by TAM AIR calorimeter. Water absorption and mechanical properties of the modified mortar were also measured according to the China standard. The result showed that the polymer dispersion mixing with cement was found to be coagulated in the very early stage under the low polymer to cement ratio, and the quantity of the polymer particles remained in the liquid is quite low within few minutes during this fast coagulation process. The fast coagulation process undermines the influence of polymer dispersion on the cement hydration and the heat evolution. But it has negative impact on the mechanical properties and water resistance. Adding of surfactant into the polymer dispersion extends the coagulation process and improves these performances.
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Wang, Ru, and Pei Ming Wang. "Hydration of Cement in the Presence of SBR Dispersion and Powder." Key Engineering Materials 466 (January 2011): 57–63. http://dx.doi.org/10.4028/www.scientific.net/kem.466.57.
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Hydration of cement in the presence of SBR dispersion and powder respectively was investigated using the methods of ITC, XRD and ESEM. The results show that both the dispersion and powder of SBR facilitate the formation, enhance the stability of AFt and inhibit the formation of C4AH13 in cement paste; the effect of the powder is more evident than the dispersion. Both the dispersion and powder of SBR delay the formation of C-S-H and Ca(OH)2 in cement paste, and the effect of the dispersion is more evident. Up to 3 days, the structure of the SBR dispersion – or powder – modified cement pastes has no significant difference with that of control paste except due to a thin polymer film on the surface. The two polymers delay the early cement hydration, but have no significant effect after 3 days.
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Wang, Ru, and Liang Zhang. "Mechanism and Durability of Repair Systems in Polymer-Modified Cement Mortars." Advances in Materials Science and Engineering 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/594672.
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This paper investigated the mechanism and durability of repair systems made of ordinary cement-based repair mortar and three kinds of polymer-modified repair mortars with old concrete, SBR dispersion, SAE dispersion, and SAE powder. By comparing the bonding properties of mortars before and after erosion, it was found that polymers could effectively improve the durability of the repair system and SAE powder had the best improvement. Micromorphology study of the repair mortar and the interface of repair mortar with old concrete through SEM showed that the polymer film formed from SAE powder whatever in the mortar or at the interface was dense and tough, the film formed from SAE dispersion was loose and weak, while the film formed from SBR dispersion was in between them, which explained the difference in the tensile bond strength and the durability of the repair systems.
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Shi, Xiao Xin, Ru Wang, and Pei Ming Wang. "Dispersion and Absorption of SBR Latex in the System of Mono-Dispersed Cement Particles in Water." Advanced Materials Research 687 (April 2013): 347–53. http://dx.doi.org/10.4028/www.scientific.net/amr.687.347.
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This paper investigates the dispersion of cement particles in water at different mix proportions using optical microscope, and the dispersion and absorption of SBR latex in the system of mono-dispersed cement particles in water using environmental scanning electron microscope (ESEM). The results show that the mono-dispersed cement can be well obtained at the water to cement ratio (mw/mc) of 10:1. The ESEM images present that SBR latex is dispersed on the surface of the cement particles as well as the solution phase. SBR latex does not prefer to be absorbed on the cement particles in spite of their opposite electric charge but chooses to be dispersed in the system proportionally. In addition, SBR particles are single-layer absorbed on the surface of cement particles in all the SBR latex to cement ratios (mp/mc). Several SBR particles absorbed on the surface of cement particle get close enough to form groups at the mp/mc of 15% and 20%. The results of this paper provide some bases for analyzing the influence of polymer on cement hydration and the microstructure formation of polymer-modified cement-based materials in a new view.
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Gruszczyński, Maciej. "Influence of Co-Polymer Dispersion Additives onto Shrinkage Strains for Cementitous Mortars and Concretes." Advanced Materials Research 287-290 (July 2011): 1097–101. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.1097.
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In the paper there is presented the influence of different types of co-polymer dispersion additives onto the magnitude of shrinkage and strength properties of cement composites. The effect of application of such additives was compared and confronted with the action of widely used classical admixture reducing shrinkage based on multi-molecular alcohol (propylene alcohol). As a result of conducted tests the significant reduction in shrinkage strains and increase in bending strength was observed due to the application of co-polymer dispersion with the amount of at least 5% of the cement mass. Reduction of shrinkage and improvement of serviceability properties to great extent prejudge the technical attractiveness of co-polymer and cement materials for the cases of concrete structures repairs and constructing industrial floors without joints.
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Wang, Ru, Dao Xun Ma, and Pei Ming Wang. "Waterproof Performance of Polymer-Modified Cement Mortar." Advanced Materials Research 687 (April 2013): 213–18. http://dx.doi.org/10.4028/www.scientific.net/amr.687.213.
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This paper tested the capillary water absorption, impermeability and cracking of cement mortars modified with three polymers respectively and founded the correlation of cracking with the waterproof performance. The results show that with the polymer content increasing, especially as the polymer/cement ratio (mp/mc) increases from 0% to 5%, the reduction in the capillary water absorption and the penetration depth of water into mortar is significant. When the mp/mc is more than 15%, the increase of the mp/mc in all mortars has little effect on the capillary water absorption and the penetration depth. For the purpose of reducing the cracking weighted value, the styrene-butadiene rubber (SBR) dispersion and the styrene-acrylic copolymer (SAE) powder are superior to the SAE dispersion. Regardless what kinds of polymers, the capillary water absorption and the penetration depth of water into mortar show exponential growth with the increasing cracking weighted value.
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Jo, Young Kug, Seon Ho Jeong, and Wan Ki Kim. "Bond Strength of Polymer Cement Slurry-Coated Rebar Using EVA Latex in Cement Concrete." Advanced Materials Research 687 (April 2013): 175–84. http://dx.doi.org/10.4028/www.scientific.net/amr.687.175.
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Polymer cement slurry(PCS) made from organic polymer dispersion and cement has good adhesion to steel, waterproofness and acid resistance due to being of polymer films formed in the cement slurry. The purpose of this study is to evaluate the mix conditions such as coating thicknesses, curing ages and polymer-cement ratios of PCS-coating material effected on improvement in bond strength of rebar coated by PCS with EVA latex in cement concrete. The test pieces are prepared with four types of polymer-cement ratio, four types of coating thickness and four types of curing age, and tested for the bond strength test. From the test results, in general, bond strength of PCS-coated rebar is better than that of uncoated rebar and epoxy-coated rebar. It is also high bond strength at curing ages of 7-day or less, and coating thicknesses of 75 µm and 100 µm. The maximum bond strength of PCS-coated rebar at curing age of 3-hour is almost same as that of curing age of 1-day and 7-day. The maximum bond strength of PCS-coated rebar with EVA at polymer-cement ratio of 50%, and coating thickness of 100 µm is about 1.41 and 1.47 times respectively, the strength of uncoated rebar and epoxy-coated rebar. It is apparent that the curing age, coating thickness and polymer-cement ratio are very important factors to improve the bond strength of PCS-coated rebar to cement concrete. We can have basic information that it can replace epoxy coated rebar by the PCS-coated rebar with curing age at 3-hour and coating thickness of 100 µm.
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Domanskaya, I. K., and Ekaterina S. Gerasimova. "Portland Cement with Mineral Fillers and Polymer Additives." Solid State Phenomena 284 (October 2018): 1063–68. http://dx.doi.org/10.4028/www.scientific.net/ssp.284.1063.
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This paper is devoted to the study of the hardening process and the mechanical properties of composite cements. There were three mineral additions and two polymer ones, namely fly ash, limestone meal and marble powder, polymer dispersion and redispersible polymer powder used. The principal possibility of combining mineral fillers in the design of composite cements is shown. It has been established that the samples of cement stone based on binders modified with redispersible polymer powder have higher compressive and flexural strength, regardless of the type of filler.
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Piotrowski, Tomasz, and Piotr Gawroński. "Chemical Resistance of Concrete-Polymer Composites – Comparison Based on Experimental Studies." Advanced Materials Research 1129 (November 2015): 123–30. http://dx.doi.org/10.4028/www.scientific.net/amr.1129.123.
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One of the main advantage of Concrete-Polymer Composites (C-PC) in relation to Cement Concrete called Ordinary Concrete is its chemical resistance. There is no European standard for testing the chemical resistance of cement based concretes and C-PC. American standards ASTM provide varied concrete tests depending on exposure conditions and mechanisms of destruction of concrete structures but there is a lack of clear criteria for the evaluation of research results by these methods. There are also requirements for monolithic floors chemical resistance - ASTM C722-04 and the requirements of the standard EN 1504-2, but they involve coating materials and cannot be directly applied to the cement concrete and C-PC. The paper presents the experimental studies of chemical resistance of C-PC in relation to OC. The investigations has been made under different environment conditions. First the samples of Ordinary Concrete (OC), Polymer Concrete (PC-1) based on vinylester resin and Polymer-Cement Concrete (PCC-1) with polyacrylic dispersion used as a co-binder were immersed for a period of time up to 168 days in a distilled water, H2SO4, MgSO4, (NH4)2SO4 and mix of the mentioned. During the storage the pH was controlled. Additionally as a reference the samples were conditioned in a climate chamber (20°C, 60% RH). The compressive strength were tested after defined periods of time. Next experiment was performed on OC and three different PCC – first modified with synthetic latex, second with polyacrylic polymer dispersion and the last with epoxy resin. The samples were immersed in H2SO4 up to 90 days. Compressive strength and mass loss after 30 and 90 days of conditioning were measured. As a reference the water immersion was used. The results obtained in this experimental program showed high chemical resistance of Polymer Concrete. PC samples obtained continuous increases of compressive strength in all examined chemically aggressive environments. It is also confirmed higher chemical resistance of Polymer-Cement Concrete modified with vinylester resin in relation to Ordinary Concrete. The second part of the program showed that the best additive to PCC among poliacrylic dispersion, synthetic latex and epoxy resin was last one. Epoxy modified PCC samples obtained best results both in compressive strength and mass loss tests
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Kwiecień, Arkadiusz, Maciej Gruszczyński, and Boguslaw Zajac. "Tests of Flexible Polymer Joints Repairing of Concrete Pavements and of Polymer Modified Concretes Influenced by High Deformations." Key Engineering Materials 466 (January 2011): 225–39. http://dx.doi.org/10.4028/www.scientific.net/kem.466.225.
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Three kinds of repair methods of cracked concrete floors are presented in the paper. One of them, based on coating using of polymer-cement composites, is discussed with presentation of the influence of different amount of styrene-butadiene co-polymer dispersion additive onto the shrinkage and strength. The next two correspond to injecting repair methods. There are also presented two different approaches in repair bonding of damaged floors. Following these ideas, results of testing of epoxy and polymer (PU) bonding of cracked specimens made of concrete and polymer-cement composites are discussed. Proposed new repair polymer flexible joints introduce energy dissipaters which allow protecting concrete pavements against large deformations. Presented comparisons of results indicate that the use of flexible polymers in repair process is efficient, what was confirmed by tests and observations of repair done at the KRK airport concrete pavement.
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Wang, Dong Min, Zhi Hua Liu, and Wei Feng Xiong. "Research on the Effect of Polycarboxylate Superlasticizers on Reheology Properties of Compound Cementitious System." Key Engineering Materials 477 (April 2011): 151–56. http://dx.doi.org/10.4028/www.scientific.net/kem.477.151.
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The rheological property is the best method which can directly reflect the dispersion property of polymer surfactants. In this paper, the rheological properties in the systems of pure cement, cement/fly ash and cement/silica fume with polycarboxylate superplasticizers of different molecular structures were studied. The effect of molecular structure on shear sress, apparent viscosity and thixotropy in compound cementitious systems was expatiated. At last, the rules of mineral admixture to the system’ rheological property and the relations between adsorption amount and rheological properties were put forward.
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Zhang, Yan, Huaqing Liu, Jialong Liu, and Ruiming Tong. "Effect of Sodium Hexametaphosphate and Trisodium Phosphate on Dispersion of Polycarboxylate Superplasticizer." Materials 12, no. 24 (December 13, 2019): 4190. http://dx.doi.org/10.3390/ma12244190.
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Enhancement in dispersion of polycarboxylate superplasticizer (PCE) could be obtained by incorporating retarders in normal concrete. The generally believed reason was that the consumption of free water and polymer at the beginning was reduced by retarding cement hydration. This theory could not convincingly explain why sodium hexametaphosphate (SHMP) was able to promote the dispersion capacity of PCE, while trisodium phosphate (TSP) could not, despite that both TSP and SHMP could obviously retard the cement hydration. The adsorption behavior of PCE and phosphate was investigated and the mechanism was analyzed in order to gain deeper understanding. The results showed that TSP and SHMP delayed the cement hydration, impeded adsorption process of PCE, and increased thickness of adsorption layer. It was interesting that TSP reduced the dispersion, but SHMP enhanced. The reason for this contradiction was due to the difference in composition of adsorption layer. In the PCE-TSP system, this layer was composed of the precipitates (formed by TSP and Ca2+) and the invalided PCE (caused by these precipitates in the immediate vicinity of the cement grains); the invalided PCE was due to the decrease of PCE dispersion. In the PCE-SHMP system, “Inner-phosphate (multi-layers) + Outer-PCE (single layer)” structure was formed to make the PCE work more effective, hence enhancing the dispersion. These results were expected to be useful for the design of highly efficient dispersants.
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Knapen, Elke, and Dionys Van Gemert. "Microstructural Analysis of Paste and Interfacial Transition Zone in Cement Mortars Modified with Water-Soluble Polymers." Key Engineering Materials 466 (January 2011): 21–28. http://dx.doi.org/10.4028/www.scientific.net/kem.466.21.
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The presence of water-soluble polymers affects the microstructure of polymermodified cement mortar. Such effects are studied by means of SEM investigation. Polyvinyl alcohol-acetate (PVAA), Methylcellulose (MC) and Hydroxyethylcellulose (HEC) are applied in a 1 % polymer-cement ratio. The polymers provide an improved dispersion of the cement particles in the mixing water. The tendency of certain water-soluble polymers to retard the flocculation of the cement particles minimizes the formation of a water-rich layer around the aggregate surfaces. They also provide a more uniform distribution of unhydrated cement particles in the matrix, without significant depletion near aggregate surfaces. Both effects enable to reduce the interfacial transition zone (ITZ). The polymers also provide a more cohesive microstructure, with a reduced amount of microcracks.
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Gruszczyński, Maciej. "Resistance of Polymer Dispersion Additive Modified Concrete to Light Liquids Action." Advanced Materials Research 941-944 (June 2014): 730–33. http://dx.doi.org/10.4028/www.scientific.net/amr.941-944.730.
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Numerous concrete and reinforced concrete structures (industrial floors, petrol station or manoeuvring park pavements, elements of sewage system) are subjected to danger of permanent or periodical action of petroleum liquids that often causes the considerable reduction in concrete strength as well as decrease of bond between concrete and steel, which usually results in structure damages. The subject of the paper is estimation of influence of polymer dispersion additive (styrene-acrylic co-polymer and styrene-butadiene latex) onto durability of concrete subjected to action of different types of light liquids. The influence of polymer dispersion additive was confronted with the action of silica fume usually applied for sealing the structure of concrete. In the paper there are presented tests results for different types of light liquids onto such cement-polymer concrete properties as: strength, penetration depth of light liquids into material structure.
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Dimmig-Osburg, Andrea. "Innovations Based on PCC." Advanced Materials Research 687 (April 2013): 369–77. http://dx.doi.org/10.4028/www.scientific.net/amr.687.369.
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Abstract. In this paper, three examples for the application of PCC are presented, which exceed the well established use as restoration material and show the great innovation potential of these materials. The first example shows an innovative development of a polymer-modified self-compacting concrete (SPCC) for the restoration of vertical facing concrete surfaces. In the second example PCC was for the first time applied as construction concrete to a bridge building. The last instance describes the potential of the SPCC for special applications in mechanical engineering. A styrene acrylic ester dispersion and different sorts of cement were used. The polymer/cement-ratio varied from 0.05 to 0.10. The water/cement-ratio depended on the requirements of the different PCC. The essential laboratory and field tests as well as the results are described.
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Pavlitschek, Thomas, Yu Jin, and Johann Plank. "Film Formation of a Non-Ionic Ethylene-Vinyl Acetate Latex Dispersion in Cement Pore Solution." Advanced Materials Research 687 (April 2013): 316–21. http://dx.doi.org/10.4028/www.scientific.net/amr.687.316.
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Environmental scanning electron microscopy (ESEM) and complementary methods were employed to study the time dependent film formation of a non-ionic latex dispersion in water @ pH 12.8 and cement pore solution. A commercial liquid ethylene-vinyl acetate latex dispersion stabilized with PVOH possessing a minimum film forming temperature (MFFT) of 3 °C and a Tg of 19 °C was employed in the study. Prior to ESEM imaging the latex dispersion was stored at room temperature and then transferred into the ESEM instrument for imaging. Subsequently, micrographs monitoring its film forming behaviour are obtained. The analysis revealed that upon removal of water, film formation occurs as a result of particle packing, particle deformation and finally particle coalescence. In synthetic cement pore solution film formation occurs faster than in water and is complete within one day. This acceleration can be ascribed to the presence of PVOH on the surface of the latex particles. In water at neutral pH, PVOH forms a shell around the latex particle and hinders the interdiffusion of the macromolecules while in cement pore solution, PVOH precipitates due to high pH and high concentration of cations. This way the latex particles can coalesce faster into a polymer film.
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Foray, G., S. Cardinal, A. Malchere, and J. M. Pelletier. "Mechanical Spectroscopy, a Tool to Characterize Cement Latex Composites." Solid State Phenomena 184 (January 2012): 399–404. http://dx.doi.org/10.4028/www.scientific.net/ssp.184.399.
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Fair dispersion of polymer and control of component grain size are key properties to achieve high performances building material (i.e. ultra high strength concrete, self-levelling floor, or exterior insulation composite system). As microstructure analysis in an organic/inorganic hydrated co-matrix material is time consuming, mechanical spectroscopy temperature analysis could characterise both the polymer and the hydrates in the same run. The temperature dependence of the storage modulusG’and the loss modulus G’’ of some composite building material was therefore measured between 173 and 470 K by mechanical spectroscopy (Dynamic Mechanical Analysis). A model material was then defined to enable DMA latex/cement interaction study. The latex was reinforced by either a microfiller (OMYA limestone) or a microfiller and a nanofiller (hydrated Lafarge cement paste CEM I 52.5 R). The latex evaluated in this study was a 210nm styrene butyl acrylate (SBA). The measurements confirmed that polymer environment was not hindered by micro or nanofiller (i.e. cement). The hydrated cement paste transformation onset was measured at 373K, but occurred at higher temperature as latex content increased. ESEM micrographs performed during heating have proven that within the hydrated cement paste many parallel cracks propagated at once, while within SBA hydrated cement paste no cracks were observed. The hydrated cement microstructure was modified by SBA, and became less sensitive to temperature increase due to SBA latex ability to deform.
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Qiao, Min, Qianping Ran, and Jiaping Liu. "Impact of Linkage Group in Comb-Like Polymer on Dispersion Properties of Cement Pastes." Polymers and Polymer Composites 21, no. 1 (January 2013): 43–50. http://dx.doi.org/10.1177/096739111302100106.
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Fareed, Muhammad A., and Artemis Stamboulis. "Nanoclay addition to a conventional glass ionomer cements: Influence on physical properties." European Journal of Dentistry 08, no. 04 (October 2014): 456–63. http://dx.doi.org/10.4103/1305-7456.143619.
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ABSTRACT Objective: The objective of the present study is to investigate the reinforcement effect of polymer-grade montmorillonite (PGN nanoclay) on physical properties of glass ionomer cement (GIC). Materials and Methods: The PGN nanoclay was dispersed in the liquid portion of GIC (HiFi, Advanced Healthcare, Kent, UK) at 1%, 2% and 4% (w/w). Fourier-transform infrared (FTIR) spectroscopy was used to quantify the polymer liquid of GICs after dispersion of nanoclay. The molecular weight (Mw) of HiFi liquid was determined by gel permeation chromatography. The compressive strength (CS), diametral-tensile strength, flexural strength (FS) and flexural modulus (Ef) of cements (n = 20) were measured after storage for 1 day, 1 week and 1 month. Fractured surface was analyzed by scanning electron microscopy. The working and setting time (WT and ST) of cements was measured by a modified Wilson's rheometer. Results: The FTIR results showed a new peak at 1041 cm−1 which increased in intensity with an increase in the nanoclay content and was related to the Si-O stretching mode in PGN nanoclay. The Mw of poly (acrylic acid) used to form cement was in the range of 53,000 g/mol. The nanoclay reinforced GICs containing <2% nanoclays exhibited higher CS and FS. The Ef cement with 1% nanoclays was significantly higher. The WT and ST of 1% nanoclay reinforced cement were similar to the control cement but were reduced with 2% and 4% nanoclay addition. Conclusion: The dispersion of nanoclays in GICs was achieved, and GIC containing 2 wt% nanoclay is a promising restorative materials with improved physical properties.
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Caimi, Stefano, Elias Timmerer, Michela Banfi, Giuseppe Storti, and Massimo Morbidelli. "Core-Shell Morphology of Redispersible Powders in Polymer-Cement Waterproof Mortars." Polymers 10, no. 10 (October 10, 2018): 1122. http://dx.doi.org/10.3390/polym10101122.
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Redispersible powders based on soft core-hard shell polymer particles can be used as additives in polymer-cement mortars. The role of this morphology on the spray-drying production of these powders and on the crack-bridging properties of the corresponding cement-based membranes is investigated. Different polymer latexes at high solid content with varied core-shell ratio, shell thickness and chemical composition (hardness) were prepared from styrene and 2-ethylhexyl acrylate monomers via semi-batch emulsion polymerization. The latexes were characterized in terms of size, composition, and glass transition temperature (T g ), and spray-dried to obtain redispersible polymer powders (RPPs) using poly (vinyl alcohol) and limestone powder as anti-caking agents. The polymer powders were mixed with a mortar mixture and redispersed in water to produce cement-based membranes, which were tested for crack-bridging properties at different temperatures. The results showed that it was not possible to spray-dry a dispersion of homogeneous polymer particles with T g of −25 ∘ C, unless these particles are protected by much harder (high T g ) shell. In particular, it was observed that a thicker shell improved the spray-ability, but lowered the crack-bridging properties of the produced membrane. A trade-off between these two was revealed to be the key for the optimal design of the polymer nanoparticles, as proven by the systematic study of the core-shell morphology reported in this work. The best compromise was shown to consist of particles larger than 300 nm, shell thickness of about 5 nm, and core-shell ratio of 97%, with styrene content in the shell not larger than 80% to avoid excessive hydrophobicity.
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Kusák, Ivo, Miroslav Lunak, Zdeněk Chobola, Michael Tupý, and Konstantinos Sotiriadis. "Characterization of Thermal Stress of Building Materials Containing Rubber Granulate by Alternating Electric Field." Advanced Materials Research 1000 (August 2014): 207–10. http://dx.doi.org/10.4028/www.scientific.net/amr.1000.207.
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The present paper deals with the application of impedance spectroscopy method to test cement-based composites after their exposure to high temperatures. A type CEM I Portland cement, siliceous sand and shredded automobile tires were used to prepare mortar specimens. The specimens differentiated in whether or not a 10 % w/w acrylic polymer binder (polymer dispersion 20 % w/w to cement mass) addition to the mortar mixture was used. The specimens were exposed to high temperatures (temperature range: 25-400 °C). Monitoring of structural changes during subjection to thermal stress is an effective way to determine the reliability of specimens structure. Based on Debye's dielectric theory, the specimens were used as dielectric models. Impedance spectra were obtained, while relative permittivity, loss factor and impedance were also measured. The results concerning electrical parameters and permittivity at each temperature were an indicator of the structural changes and its reliability.
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Pavlitschek, Thomas, Markus Gretz, and Johann Plank. "Effect of Ca2+ Ions on the Film Formation of an Anionic Styrene/n-Butylacrylate Latexpolymer in Cement Pore Solution." Advanced Materials Research 687 (April 2013): 322–28. http://dx.doi.org/10.4028/www.scientific.net/amr.687.322.
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Several methods were employed to study the time dependent film formation of a self synthesized anionic latex dispersion in water and cement pore solution. First, a model carboxylated styrene/n-butyl acrylate latex dispersion possessing a minimum film forming temperature (MFFT) of 18 °C and a glass transition temperature (Tg) of 30 °C was synthesized via emulsion polymerization. Next, its film forming behaviour was studied at 40 °C, using an ESEM instrument. The analysis revealed that upon removal of water, film formation occurs as a result of particle packing, particle deformation and finally particle coalescence. Film formation is significantly hindered in synthetic cement pore solution. This effect can be ascribed to adsorption of Ca2+ ions onto the surface of the anionic latex particles and to interfacial secondary phases. This layer of adsorbed Ca2+ ions hinders interdiffusion of the macromolecules and subsequent film formation of the latex polymer.
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Łukowski, Paweł, Piotr Woyciechowski, Grzegorz Adamczewski, Magdalena Rudko, and Kamil Filipek. "Curing of Polymer-Cement Concrete – Search for a Compromise." Advanced Materials Research 1129 (November 2015): 222–29. http://dx.doi.org/10.4028/www.scientific.net/amr.1129.222.
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In this paper there are presented results of research carried out for establishing the most favourable scenario of curing of the Polymer-Cement Concrete (PCC). The general recommendations for PCC point to the need of alternating conditions of curing of PCC. Polymer-cement concrete should be first cured in the wet conditions for effective hydration of Portland cement and then in air-dry conditions for polymer setting. According to the literature, the often accepted curing regime of PCC covers 5 days of wet curing and then the air-dry curing until the time of testing. According to the European Standards, the wet period should last 3 days. However, the authors` experiences show that the aforementioned scenarios is not the optimum one. The studies presented in this paper are the part of the larger research program, which – according to the authors` intention – should lead to the establishing of the optimum curing regime for PCC. The tests were carried out using two types of polymer modifiers: two-component epoxy resin and water dispersion of polyacrylates, introduced into the cement concrete mix. The following properties were accepted as the criteria of evaluation of PCC curing effectiveness: compressive strength, tensile splitting strength, surface tensile strength (by pull-off method), wear resistance, water penetration under pressure. These properties were evaluated after 28 days of curing according to the various regimes. The tests showed that the extension of the wet curing period beyond 5 days was favourable for the technical properties of PCC. The establishing of the optimum time of wet curing, however, needs further research. Also, some conclusions were formulated about the usefulness of the various properties as the criteria of PCC curing efficiency evaluation.
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Lv, Shenghua, Haoyan Hu, Yonggang Hou, Ying Lei, Li Sun, Jia Zhang, and Leipeng Liu. "Investigation of the Effects of Polymer Dispersants on Dispersion of GO Nanosheets in Cement Composites and Relative Microstructures/Performances." Nanomaterials 8, no. 12 (November 22, 2018): 964. http://dx.doi.org/10.3390/nano8120964.
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This study focused on the uniform distribution of graphene oxide (GO) nanosheets in cement composites and their effect on microstructure and performance. For this, three polymer dispersants with different level of polar groups (weak, mild, and strong) poly(acrylamide-methacrylic acid) (PAM), poly(acrylonitrile-hydroxyethyl acrylate) (PAH), and poly(allylamine-acrylamide) (PAA) were used to form intercalation composites with GO nanosheets. The results indicated that GO nanosheets can exist as individual 1–2, 2–5, and 3–8 layers in GO/PAA, GO/PAH, and GO/PAM intercalation composites, respectively. The few-layered (1–2 layers) GO can be uniformly distributed in cement composites and promote the formation of regular-shaped crystals and a compact microstructure. The compressive strengths of the blank, control, GO/PAM, GO/PAH, and GO/PAA cement composites were 55.72, 78.31, 89.75, 116.82, and 128.32 MPa, respectively. Their increase ratios relative to the blank sample were 40.54%, 61.07%, 109.66%, and 130.29%, respectively. Their corresponding flexural strengths were 7.53, 10.85, 12.35, 15.97, and 17.68 MPa, respectively, which correspond to improvements of 44.09%, 64.01%, 112.09%, and 134.79%.
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Samchenko, Svetlana V., Irina V. Kozlova, and Olga V. Zemskova. "Model and Mechanism of Stabilization of Carbon Nanotubes with Placticizer on the Basis of Sulfonated Naphthalene Formaldehyde Resins." Materials Science Forum 931 (September 2018): 481–88. http://dx.doi.org/10.4028/www.scientific.net/msf.931.481.
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The entry presents studies of the effect of dispersion temperature on the deposition rate of CNTs in the presence of a plasticizer based on sulfonated naphthalene formaldehyde resins, on the dispersed composition of CNTs in aqueous and aqueous-polymer dispersion media and on the strength characteristics of samples with stabilized CNTs. It was established that the ultrasonic dispersion of aqueous suspensions of CNTs in the presence of a plasticizer based on sulfonated naphthalene formaldehyde resins at an ultrasonic vibration frequency of 44 kHz; dispersion temperature - 25 ± 2 °C; dispersion time - 10 - 30 minutes is capable of ensuring the stability of CNTs suspensions for 7 days or more. The mechanism of stabilization of aqueous suspension of CNTs by a plasticizer based on sulfonated naphthalene formaldehyde resins is presented. It has been established that the stabilization of CNTs is achieved by fixing the functional groups of the plasticizer on the surface of the nanoparticle, the nonpolar component of which ensures the formation of a high-viscosity interlayer between the CNTs particles and the dispersion medium, and the polar component is the formation of a double electric layer (DEL) that promotes the micellization of CNTs. As a result, the CNTs stabilized with sulfonaphthalene formaldehyde are evenly distributed in the volume of the cement system, causing the production of cement stone with enhanced performance properties.
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Song, Jianjian, Mingbiao Xu, Weihong Liu, Xiaoliang Wang, Peng Xu, Feng Huang, and Yonggong Pan. "Thermoplastic Rubber (TPR) Modified by a Silane Coupling Agent and Its Influence on the Mechanical Properties of Oil Well Cement Pastes." Advances in Materials Science and Engineering 2019 (January 2, 2019): 1–11. http://dx.doi.org/10.1155/2019/3587081.
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The surface hydrophilicity of thermoplastic rubber (TPR) is poor, and the effect of using it directly in oil well cement is not good. TPR was modified by different silane coupling agents, and the hydrophilicity of the modified TPR was studied by Fourier-transform infrared (FT-IR) spectroscopy and dispersion stability photography. The application effect of modified TPR in oil well cement slurry was also evaluated. The fracture surface morphology of TPR cement stone was observed by macrophotography and scanning electron microscopy (SEM). The results demonstrated that the hydrophilicity of TPR particles was improved after modification with silane coupling agent 3-methacryloxypropyltrimethoxysilane (KH570), and its application effect in cement slurry was excellent. Compared with the pure cement paste, the compressive strength of the cement paste with addition of TPR modified by KH570 was reduced, but the flexural strength and impact strength of the cement paste were effectively enhanced. Moreover, the modified TPR greatly improved the deformation capacity and decreased the elastic modulus of the cement paste. The modified TPR particles formed a plastic polymer network structure in the cement stone and penetrated the cement hydration products, filling in the cement paste to form a flexible structural center. Thus, it improved the mechanical properties and reduced the brittleness of cement paste.
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Tupý, Michael, Daniela Štefková, Konstantinos Sotiriadis, Lukáš Krmíček, Ladislav Carbol, and Vít Petranek. "Recycled Poly(Vinyl Butyral) Used as a Barrier to Prevent Mortar Carbonation." Advanced Materials Research 1000 (August 2014): 28–34. http://dx.doi.org/10.4028/www.scientific.net/amr.1000.28.
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The paper deals with testing of CO2 diffusivity through poly (vinyl butyral) (PVB) layers and their efficiency to serve as barriers against cement mortar carbonation. Two different types of PVB were tested; PVB sheet made from original extruded PVB polymer and PVB sheet made from PVB dispersion obtained from recycled windshields. The first part of the work was focused on testing CO2 diffusion when polymer sheets were exposed to a CO2 atmosphere (10% v/v CO2) with 0% RH. The excellent barrier capability against CO2 permeability of both types of polymer layers was observed. In the second part, mortar specimens were exposed for 23 days to two different carbonation regimes (laboratory conditions and chamber with CO2 atmosphere (1% v/v CO2) and 60% RH), having been coated or not with recycled PVB dispersion. Compressive strength tests, carbonation depth measurements and acoustic measurements (impact-echo method) were performed. The results showed the alternation of the compressive strength values depending on whether PVB coating was used or not. Both phenolphthalein test and impact-echo method confirmed the protective effect of PVB layer against mortar carbonation.
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Verné, Enrica, Filippo Foroni, Giovanni Lucchetta, and Marta Miola. "Antibacterial and Bioactive Composite Bone Cements." Current Materials Science 12, no. 2 (March 3, 2020): 144–53. http://dx.doi.org/10.2174/1874464812666190819143740.
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Background:: Peri-prosthetic infections are characterized by high resistance to systemic antibiotic therapy. In this work, commercial PMMA-based bone cement has been loaded with a bioactive glass doped with silver ions, with the purpose to prepare composite bone cement containing a single inorganic phase with both bioactive and antibacterial properties, able to prevent bacterial contamination. Methods:: The glass distribution in the polymeric matrix, the composites radio-opacity, the bending strength and modulus, the morphology of the fracture surfaces, the bioactivity in Simulated Body Fluid (SBF) and the antibacterial effect were evaluated. The glass particles dispersion in the polymeric matrix and their exposition on the polymer surface have been assessed by morphological and compositional characterizations via Scanning Electron Microscopy (SEM) and Energy Dispersion Spectroscopy (EDS). Results:: The introduction of the silver-doped bioactive glass allowed imparting an intrinsic radio-opacity to the cement. The bending strength and modulus were influenced by the glass preparation, amount and grain-size. The polymeric matrix did not affect the composite ability to induce hydroxyapatite precipitation on its surface (bioactivity). Moreover, antibacterial test (inhibition halo evaluation) revealed a significant antibacterial effect toward S. aureus, Bacillus, E. coli and C. albicans strains. Conclusion:: The obtained results motivate further investigations and future in vivo tests.
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Fořt, Jan, Anton Trník, and Zbyšek Pavlík. "Latent Heat Storage in Plasters with Incorporated PCM Water Dispersion." Materials Science Forum 824 (July 2015): 1–6. http://dx.doi.org/10.4028/www.scientific.net/msf.824.1.
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The sustainability principles in building sector promote a development of new building materials and products directly designated for improvement of the thermal performance of buildings related to the energy saving for the interior climate conditioning. In order to comply with this concept and improve the thermal comfort of buildings environment, incorporation of phase change materials (PCMs) into the construction elements giving ability to store and release heat looks like a beneficial material solution. On this account, the mechanical, rheological and thermal properties of cement-lime dry plaster mixture with addition of 4, 8 and 12 mass% of PCM water dispersion are experimentally investigated in the paper. The increasing amount of applied PCM admixture causes the significant improvement of the plaster heat storage capacity in dependence on temperature exposure applied in the performed DSC experiment. Contrary to this positive finding, the higher content of tested polymer microencapsulated PCM in plaster matrix leads to the lower mechanical strength. However, it is still sufficient for construction applications.
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Fareed, Muhammad A., and Artemis Stamboulis. "Effect of Nanoclay Dispersion on the Properties of a Commercial Glass Ionomer Cement." International Journal of Biomaterials 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/685389.
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Objective.The reinforcement effect of polymer-grade montmorillonite (PGV and PGN nanoclay) on Fuji-IX glass ionomer cement was investigated.Materials and Method.PGV and PGV nanoclays (2.0 wt%) were dispersed in the liquid portion of Fuji-IX. Fourier-transform infrared (FTIR) spectroscopy and gel permeation chromatography (GPC) were used to quantify acid-base reaction and the liquid portion of GIC. The mechanical properties (CS, DTS, FS, andEf) of cements (n= 20) were measured at 1 hour, 1 day, and 1 month. The microstructure was examined by cryo-SEM and TEM.Results. FTIR shows that the setting reaction involves the neutralisation of PAA by the glass powder which was linked with the formation of calcium and aluminium salt-complexes. The experimental GICs (C-V and C-N) exhibited mechanical properties in compliance to ISO standard requirement have higher values than Fuji-IX cement. There was no significant correlation of mechanical properties was found between C-V and C-N. The average Mw of Fuji-IX was 15,700 and the refractive index chromatogram peak area was 33,800. TEM observation confirmed that nanoclays were mostly exfoliated and dispersed in the matrix of GIC.Conclusion. The reinforcement of nanoclays in GICs may potentially produce cements with better mechanical properties without compromising the nature of polyacid neutralisation.
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Angelescu, Nicolae, Ioana Ion, Darius Stanciu, José Barroso Aguiar, Elena Valentina Stoian, and Vasile Bratu. "Special Concrete with Polymers." Scientific Bulletin of Valahia University - Materials and Mechanics 14, no. 11 (October 1, 2016): 7–10. http://dx.doi.org/10.1515/bsmm-2016-0001.
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Abstract The development of polymeric materials offers new perspectives of science and technology due to their outstanding properties. These properties are obtained either due to the effect of dispersion polymers and their polymerization either due to their intervention in structure formation. They were prepared epoxy resin polymer concrete, Portland cement, coarse and fine aggregate and to evaluate the influence of resin dosage on microstructures and density of such structures reinforced concrete mixtures. The paper detailing the raw materials used in experimental works and structural properties of concrete studied.
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Kovalenko, O. V. "Modern cement-based waterproofings for hydraulic structures protection." Міжвідомчий тематичний науковий збірник "Меліорація і водне господарство", no. 1 (June 25, 2020): 175–85. http://dx.doi.org/10.31073/mivg202001-222.
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Hydrotechnical structures of water management and land reclamation complex from the moment of commissioning are subject to aggressive environmental effects: hydrostatic water pressure, alternating freezing and thawing, moistening and drying, corrosive action of salts dissolved in water, dynamic action of ice. The trouble-free operation of structures with long-term aggressive environmental factors is possible only in the case of providing their protection (reinforcement) with effective insulating, anticorrosive, high-strength, wear-resistant and cavitation-resistant composite materials.
Waterproofing coatings, which arrange on the surface of reinforced concrete structures, plays an important role in ensuring operational reliability and durability of hydraulic structures. Having rather low cost of waterproofing coatings as compared to the cost of structures the fate of their responsibility in terms of ensuring the durability and operational reliability of the structures is high enough. Waterproofing coatings serve as a barrier to an aggressive environment and thus protect structures from destruction.
Notwithstanding the importance of waterproofing protection, this issue is not given due attention today. Therefore, filtration of water through the structures of water-reclamation facilities is a common phenomenon. Water filtration through damaged concrete of hydraulic structures causes dissolution and leaching of water with calcium hydroxide (leaching), which further causes the decomposition of other components of the cement stone and leads to the dilution of the concrete structure and to the strengthening of drip filtration. Drip filtration increases over time, then jet filtration develops, which can lead to complete destruction of the structure. Therefore, providing waterproofing protection of structures is an important engineering task in their construction and operation.
One of the determining factors for the effectiveness of waterproofing is the right selection of material. Traditional waterproofing materials on a bituminous basis have insufficient physical-mechanical properties and durability. However, modern technologies of waterproofing protection of concrete and reinforced concrete structures are based on the use of effective composite materials with high physical, mechanical and protective properties. Depending on the type of binder, waterproofing materials can be based on bitumen, bituminous-mineral, bitumen-polymer, coal, polymer compositions, as well as on the basis of cements and polymer cements.
The selection of a waterproofing material should be made taking into account the specifics of the operating environment and the conditions of use. The most common in the construction of gluing roll materials on a bituminous basis can only partially satisfy the need for hydraulic engineering, as for the waterproofing of hydraulic structures. There are high requirements with regard to the aggressiveness of the environment and their low repairsability.
The most promising for use in the technology of arrangement of waterproofing coatings on concrete and reinforced concrete structures of hydraulic engineering facilities of water management and reclamation complex are polymer cement mixtures, binders in which are Portland cement modified with polymer latex dispersion powder (for two-component).
Creation of effective polymer cement waterproofing compositions is based on optimization of the ratio of interpenetrating meshes of polymers and crystal matrix hydrates. Modification of cement systems by polymers allows to increase adhesion and deformation characteristics, fracture resistance and corrosion resistance of polymer cement composites. Depending on the components included in the mixture, waterproofing coatings may be rigid or elastic. Rigid formulations are a water-mixed, dry mixture that includes a vinyl acetate copolymer and designed for waterproofing concrete and reinforced concrete structures with low water filtration. Elastic waterproofing materials are usually two-component. These materials are used for waterproofing structures that are susceptible to deformation, as well as surfaces with a high degree of water filtration and where cracks up to 1 mm are formed. Elastic two-component formulations are dry mixtures with the addition of redispersible polymer powders. They consist of two components: a dry mixture of modified fine cement and aqueous latex polymer, usually acrylic.
The content of polymer latex in the mixture has a significant effect on the rheological properties of polymer-cement mixtures and on the physical and mechanical properties of waterproofing coatings made of them. Thus, the introduction of a redispersible polymer powder Axilat L 8262 in a waterproofing mixture in the amount of up to 10% by weight of cement increases the mobility of the mixture from 3,2 to 8,0 cm, increases the adhesive strength of the coating to concrete from 0,45 to 1,95 MPa, increases its bending strength from 6,9 to 7,9 MPa, reduces its water absorption in 24 hours from 7,02% to 0,35% .
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Irekti, A., M. Oualit, H. Siahmed, D. Buncianu, and F. Zibouche. "Effect of Black Liquor from Date Palm on the Workability and Compressive Strength of Portland Cement and Concrete." Advances in Materials Science 19, no. 3 (September 1, 2019): 5–18. http://dx.doi.org/10.2478/adms-2019-0013.
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AbstractLignin is the second most abundant natural polymer. Due to the high content of carbon and hydrogen (C-H, C-C, C=O), it can be used as a potential dispersant for cement matrix. The objective of this study is to extract lignin from date palm and study its effect in the form of black liquor (BL) on the rheological and physic-mechanical properties of the cements and concrete. The lignin in black liquor form represents approximately 30 wt% dry weight of date palm. It is a heteropolymer composed primarily of methoxylated phenylpropylene alcohol monomeric units interconnected by a variety of stable carbon-carbon and carbon-oxygen-carbon (ether and esters) linkages. The results found show the positive effect on the workability of cement and concrete and confirms its dispersion effect by improving compressive strength of concrete during the early and the later ages of hydration.
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Liu, Zhi Yong, Chong Cui, and Li Li. "Study on Preparation and Dispersion Effect of Polycarboxylate Superplasticizer with Broken Dentiform Structure." Advanced Materials Research 250-253 (May 2011): 984–89. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.984.
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Based on the analysis of the chemical structure of polycarboxylate-type SPs grafted PEO side chains, as well as sulfonic and carboxylic acid groups, a kind of polycarboxylate-based SPs grafted varied PEO side chains were synthesized by using radical polymerisation techniques.The relative dispersing effectiveness of the SPs was evaluated in cement paste and concrete by measuring paste flow and concrete slumps. The test results indicat that the copolymers with shorter PEO side chains (with 9 and 14 EO units) give lower initial dispersing power but higher time retention,with the prolonging of PEO side chains the higher initial dispersing effect and the lower time retention can be received. The excellent dispersing property and time retention of synthesized SPs for cementious systems can be achieved by grafted long side chain(with 45 EO units) integrated with short side chain(9 or 14 EO) at the backbone of anionic polymer.
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Fořt, Jan, Anton Trník, and Zbyšek Pavlík. "Cement-Lime Plaster with PCM Addition – A Perspective Material for Moderation of Interior Climate." Key Engineering Materials 707 (September 2016): 43–50. http://dx.doi.org/10.4028/www.scientific.net/kem.707.43.
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The interior temperature and relative humidity are important parameters in order to achieve healthy, comfortable, sustainable, and energy efficient indoor environment. In this paper, cement-lime plaster with PCM addition is studied as a perspective material for moderation of indoor temperature and humidity fluctuations. Commercial dry plaster mixture is modified by PCM addition based on the water dispersion of polymer microencapsulated paraffinic wax. The dosage of PCM is 4, 8, and 12 mass% related to the dry mass of plaster mixture. For the developed plasters, basic physical, thermal and hygric properties are measured. Incorporation of PCM into the cement-lime matrix lead to the substantial increase of the heat storage capacity in dependence on temperature as well as to the improvement of moisture buffer value of the newly developed composites which brings efficient way to reduce daily moisture variations. The obtained data can find use in attaining the higher indoor climate stability with lower energy consumption and operational cost.
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Chia, Leonard, Gina Blazanin, Ying Huang, Umma Salma Rashid, Pan Lu, Senay Simsek, and Achintya N. Bezbaruah. "Surface Treatment of Carbon Nanotubes Using Modified Tapioca Starch for Improved Force Detection Consistency in Smart Cementitious Materials." Sensors 20, no. 14 (July 17, 2020): 3985. http://dx.doi.org/10.3390/s20143985.
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The remarkable mechanical properties and piezo-responses of carbon nanotubes (CNT) makes this group of nanomaterials an ideal candidate for use in smart cementitious materials to monitor forces and the corresponding structural health conditions of civil structures. However, the inconsistency in measurements is the major challenge of CNT-enabled smart cementitious materials to be widely applied for force detection. In this study, the modified tapioca starch co-polymer is introduced to surface treat the CNTs for a better dispersion of CNTs; thus, to reduce the inconsistency of force measurements of the CNTs modified smart cementitious materials. Cement mortar with bare (unmodified) CNTs (direct mixing method) and surfactant surface treated CNTs using sodium dodecyl benzenesulfonate (NaDDBS) were used as the control. The experimental results showed that when compared with samples made from bare CNTs, the samples made by modified tapioca starch co-polymer coated CNTs (CCNTs) showed higher dynamic load induced piezo-responses with significantly improved consistency and less hysteresis in the cementitious materials. When compared with the samples prepared with the surfactant method, the samples made by the developed CCNTs showed slightly increased force detection sensitivity with significantly improved consistency in piezo-response and only minor hysteresis, indicating enhanced dispersion effectiveness. The new CNT surface coating method can be scaled up easily to cater the potential industry needs for future wide application of smart cementitious materials.
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A. Jadhav, Sushilkumar, Roberta Bongiovanni, Daniele L. Marchisio, Daniela Fontana, and Christian Egger. "Surface modification of iron oxide (Fe2O3) pigment particles with amino-functional polysiloxane for improved dispersion stability and hydrophobicity." Pigment & Resin Technology 43, no. 4 (July 1, 2014): 219–27. http://dx.doi.org/10.1108/prt-07-2013-0057.
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Purpose – The purpose of the present study is to use an amino-functional polysiloxane for the surface modification of red iron oxide (Fe2O3) pigment particles for their improved dispersion stability and hydrophobicity and to study the chemical interactions of polysiloxanes with the particle surface. Design/methodology/approach – Surface-treated red Fe2O3 pigment particles were prepared by treatment of the particles with different quantities of the (aminopropylmethylsiloxane)-dimethylsiloxane copolymer in concentrated suspensions in water. The samples were analysed with different instrumental and spectroscopic techniques to study the interaction of the polysiloxane with the particle surface and the effect of the surface treatment of the particles on their dispersion stability and hydrophobicity. Findings – Chemisorption of the amino-polysiloxane onto the surface of Fe2O3 particles resulted in stable layers which turned out to be helpful in improving greatly the dispersion stability of the particles as shown by the Static Light Scattering and Dynamic Light Scattering results. Formation of a polysiloxane coating onto the surface of the pigment particles was confirmed by studying the interactions of the polymer molecules with Fe2O3 surfaces by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy techniques. Practical implications – The surface-treated red Fe2O3 particles with improved dispersion stability can be important components of various formulations in applications such as the colouring of the cement or inorganic pigment-based paint formulations. Originality/value – The study provides mechanistic insights about the interactions of amino-polysiloxane with the red Fe2O3 particles. The process of surface modification of red Fe2O3 particles with the amino-functional polysiloxane showed increased hydrophobicity and dispersion stability which is an important requirement of the pigment-based formulations in real applications.
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Balabanov, Vadim, and Ksenia Putsenko. "Modification of fine-grained polymer concrete with microsilica." MATEC Web of Conferences 212 (2018): 01010. http://dx.doi.org/10.1051/matecconf/201821201010.
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At present, one of the most promising areas in construction is the modification of concrete by means of a complex of modifying additives and production wastes that will allow to obtain concrete with improved technical and operational characteristics and solve a number of problems: import substitution and nanotechnology. The aim of scientific research is the development of new technologies for obtaining concrete with enhanced performance characteristics, provided that raw materials, energy and labor costs are minimized. The article presents the results of research work on the development of fine-grained polymer concrete, modified with microsilica. In the framework of the study, a literature review for the last 68 years has been conducted, devoted to the experience of using microsilica and polymers in concrete construction as a modifier for building materials. The main characteristics of the starting materials and modifying additives are determined. A study was conducted to determine the effect of various modifying additives on the physicomechanical characteristics of fine-grained concrete. The main rheological properties and strength characteristics of the entire spectrum of the investigated compositions are determined. A microscopic study of the structure was carried out. The result of scientific research is the establishment of an optimal combination of additives, the development of cement concrete with the use of microsilica and acrylic dispersion and the determination of the effect of additives on the physical and mechanical properties.
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Soto, Diana, Orietta León, José Urdaneta, Alexandra Muñoz-Bonilla, and Marta Fernández-García. "Modified Starch as a Filter Controller in Water-Based Drilling Fluids." Materials 13, no. 12 (June 20, 2020): 2794. http://dx.doi.org/10.3390/ma13122794.
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Herein, the effectiveness of an itaconic acid (IA) graft copolymer on native corn starch (NCS) as a filter control agent in fresh water-based drilling fluids (WBDFs) was evaluated. The copolymer (S-g-IA_APS) was synthesized by conventional radical dispersion polymerization using the redox initiation system (NH4)2S2O8/NaHSO3. The modification of the starches was verified by volumetry, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Then, three WBDFs were formulated in which only the added polymer (NCS, S-g-IA_APS, and a commercial starch (CPS)) was varied to control the fluid losses. The physico-chemical, rheological, and filtering properties of the formulated systems were evaluated in terms of density (ρ), pH, plastic viscosity (µp), apparent viscosity (µa), yield point (Yp), gel strength (Rg), and filtrated volume (VAPI). In order to evaluate the resistance to temperature and contaminants of the WBDFs, they were subjected to high pressure and high temperature filtering (VHPHT). The filter control agents were also subjected to aging and contamination with cement and salt. The S-g-IA_APS addition improved the filtering behavior at a high pressure and temperature by 38%.
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Liu, Yanzhu, Liang Wang, Ke Cao, and Lei Sun. "Review on the Durability of Polypropylene Fibre-Reinforced Concrete." Advances in Civil Engineering 2021 (June 4, 2021): 1–13. http://dx.doi.org/10.1155/2021/6652077.
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Polypropylene fibre (PPF) is a kind of polymer material with light weight, high strength, and corrosion resistance. The crack resistance of concrete can be improved by adding PPFs. PPF can optimize the pore size distribution of concrete. As a result, the durability of concrete is significantly enhanced since PPF can block the penetration of water or harmful ions in concrete. This paper summarizes the influence of polypropylene fibre on the durability of concrete, including drying shrinkage, creep, water absorption, permeability resistance, chloride ion penetration resistance, sulfate corrosion resistance, freeze-thaw cycle resistance, carbonation resistance, and fire resistance. The authors analysed the effects of fibre content, fibre diameter, and fibre hybrid ratio on these durability indexes. The durability property of concrete can be further improved by combining PPFs and steel fibres. The drawbacks of PPF in application in concrete are the imperfect dispersion in concrete and weak bonding with cement matrix. The methods to overcome these drawbacks are to use fibre modified with nanoactive powder or chemical treatment. At last, the authors give the future research prospects of concrete made with PPFs.
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Shvarczkopf, Valeriya È., Irina A. Pavlova, and Elena P. Farafontova. "Utilization of Porcelain Tile Polishing Residue." Defect and Diffusion Forum 410 (August 17, 2021): 699–703. http://dx.doi.org/10.4028/www.scientific.net/ddf.410.699.
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The research focuses on the properties of by-products formed in the production of porcelain stoneware: polishing residue and residue of the mixture-preparation shop. The polishing residue consists of glassy phase (80%), quartz (14%), mullite (5%). Residue of the mixture-preparation shop consists of quartz (~ 18%), muscovite (~ 6.9%), kaolinite (~ 20.5%), calcium-sodium feldspar (~ 51.4%), diopside (~ 2.98%). Polishing residue occurs when polishing porcelain stoneware to create a glossy surface and when polishing the side faces of porcelain stoneware to obtain accurate tile geometry. The particle size of the polishing residue is less than 0.2 mm, and the residue of the mixture-preparation shop is less than 40 microns. Residue of the mixture-preparation shop is formed when cleaning equipment: mills, mixers, slipways, etc. The ways of utilization of by-product are follows: as a filler for the silicate production; for polymer-cement, water-dispersion and oil paints; as a filler for the production of roofing materials, bituminous roofing mastics based on organic binders; raw materials for the production of foam glass materials and products.
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Francke, Barbara, and Artur Piekarczuk. "Experimental Investigation of Adhesion Failure between Waterproof Coatings and Terrace Tiles under Usage Loads." Buildings 10, no. 3 (March 17, 2020): 59. http://dx.doi.org/10.3390/buildings10030059.
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This paper analyses the mechanism of the loss of functional properties of water-impermeable products used under ceramic tiles bonded with adhesives. Recorded damages were caused by selected ageing factors and were measured by the loss of adhesion of individual layers of the set. The analyzed phenomenon is found mainly on terraces and balconies located in a mid-European transitional climate, i.e., exposed to temperatures passing through 0 °C for three seasons a year. The tests reflected the action of three main functional factors, i.e., temperatures, water and freeze/thaw cycles. Tested waterproof coatings were grouped into three types, i.e., dispersion, cementitious and reaction resin-based products. Research kits consisted of liquid-applied water-impermeable products laid on a concrete substrate, adhesives and tiles. Comparing the effects of the action of the above-mentioned ageing factors revealed that water has the greatest impact on the reduction of the tensile adhesion strength of such sets. The adhesion of waterproof coatings to the concrete substrate showed higher values than the adhesion between the waterproof coating and the tile adhesive layers, regardless of the coating material. Both for samples not exposed to ageing factors, and for those exposed to such impacts, failure usually occurred in the adhesive layer or between the tile adhesive and the waterproof coating, without damaging the waterproof layer. The loss of adhesion of finishing layers to the substrate was not accompanied by a loss of tightness of the waterproof coating. The impact of negative water ageing was particularly destructive on the adhesion of cement-based tile adhesives to waterproof coatings made of polymer with a water dispersion of absorbability above 7% (V/V). There was no correlation among the results of adhesion of the finishing layers to the waterproofing layer after the action of the three ageing factors, i.e., water contact, elevated temperature and freeze/thaw cycles.
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Weichold, Oliver, Markus Hojczyk, Alina Adams, Alexandra Olaru, and Helge Stanjek. "Microstructural Analysis during the Hydration of Cement-in-Polymer Coatings." Key Engineering Materials 466 (January 2011): 159–66. http://dx.doi.org/10.4028/www.scientific.net/kem.466.159.
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Cement-in-polymer (c/p) dispersions allow the full utilisation of the reinforcing abilities of multifilament rovings in concrete. In this work the role of the polymer properties on the performance of the c/p dispersions is investigated and discussed. Two model polymers are chosen and c/p dispersions made with these are investigated regarding the water ingress velocity (NMR), the phase development during cement hydration (XRD), and the microstructure after cement hydration (SEM). Best mechanical performance is achieved with the hydrophobic poly(vinyl acetate) which regulates the water ingress and causes a slow hydration of the cement.
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Shuyskiy, Anatoliy I., Sergey A. Stel'makh, Evgeniy M. Shcherban', and Mikhail G. Kholodnyak. "Investigation of the Influence of the Initial Composition of Heavy Concrete Designed for the Manufacture of Ring-Section Products on its Properties." Materials Science Forum 931 (September 2018): 508–14. http://dx.doi.org/10.4028/www.scientific.net/msf.931.508.
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The authors conducted the analysis of scientific and technical references relating to the issue of increasing maintenance reliability of pre-stressed reinforced concrete by means of taking into account concrete non-homogeneity in the calculations of strength, deformability and crack resistance of the reinforced concrete products with annular section. The authors stated the opportunity to increase the quality of concrete intended for centrifugation by means of regulating the properties of used materials. It was identified that applying disperse-reinforced fibers resulted in increase in bending tensile strength, decrease in shrinkage, increase in crack resistance and material resistance towards alternate freezing and thawing, drying and humidification cycles. Upon the results of conducted research and comparison of the properties of various fibers, the authors obtained regularities and application rules on fiber use and gave recommendations in terms of applying one of another fiber type. On the basis of the analysis of obtained results the authors made the conclusion that the highest effect in all tests was observed at the application of basalt fibers as they provide for a higher dispersion of cement rock reinforcement while the basalt fiber itself has a higher strength comparing with any other polymer fiber. Further, the authors conducted the research of mechanical properties characteristic for test beams made of heavy concrete to manufacture the annular section products by means of centrifugation. The obtained dependences allow making a conclusion that the percentage ratio of applied crushed stone fractions Fr 5-10 / Fr 5-20 = 50 / 50 under otherwise equal conditions has the highest influence on the heavy concrete ground strength.
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Larsen, Oksana, Marsel Nurtdinov, Viktoria Shvetsova, and Ekaterina Fomina. "Influence of expansive additive on formation of fresh polymer modified pastes." MATEC Web of Conferences 239 (2018): 01023. http://dx.doi.org/10.1051/matecconf/201823901023.
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Chemical admixtures are widely used in cement-based mixtures to reduce water demand, increase working time or accelerate strength development. The application of water-soluble polymers in building industry is increasing. The performance of cement mortars and concretes can be improved by the modification of their structure with additives of polymers. The use of polymers in cement-based compositions can decrease the intensity of hydration kinetic and increase the shrinkage deformation. Hardening of polymer-modified cement-based mixtures is associated with drying shrinkage which can significantly decrease crack resistance of cement concretes, especially in the case of polymer dispersions. The influence of polymer admixture with expansive additive on formation of cement-based pastes was investigated. Structure formation of fresh polymer modified cementitious mixtures with expansive additive was experimentally investigated by heat evolution behavior. Structure formation as a function of time and depends from initial mixture design properties such as water-cement ratio, polymer-cement ratio and content of expansive additive.
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Jo, Young-Kug. "Adhesion in tension of polymer cement mortar by curing conditions using polymer dispersions as cement modifier." Construction and Building Materials 242 (May 2020): 118134. http://dx.doi.org/10.1016/j.conbuildmat.2020.118134.
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Loganina, Valentina I., and Tatyana V. Uchaeva. "Statistical assessment of damnification risk due to inconformity of paint coating quality." Vestnik MGSU, no. 11 (November 2019): 1449–55. http://dx.doi.org/10.22227/1997-0935.2019.11.1449-1455.
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Introduction. In connection with the increase in the proportion of paint compositions in the decoration of buildings and the actualization of the building structure finishing quality issues, it is necessary to determine the degree of damnification risk if the quality of paints and coatings does not conform to requirements.
Materials and methods. In order to assess the risk in the work, the study used polyvinyl acetate cement (PVAC) paint, MA-15 oil paint, PF-115 alkyd paint, AK-111 water-dispersion acrylic paint, KO-168 organic-silicone paint, and PI polymer lime paint as paint compositions. The risk was considered as the probability of an event that harms the paint coating. In addition to this, a calculation of the risk R as the expected damage Y due to destruction of the coating was performed.
Results. The research has established that some coatings are characterized by lower uniformity of adhesion strength values than it is required on the grounds of the relation between the actual and normative coefficients of variation. The values of risk r indicate that the probability of adhesive destruction is minimal. The calculation of the risk R as the expected damage Y because of the coating destruction due to the violation of adhesion showed that the maximum risk R values are from 0.068 to 11.18 rubles per square meter.
Conclusions. It is established that the probability of paint coating adhesive destruction is minimal. The values of risk as expected damage because of coating adhesive destruction are from 0.068 to 11.18 rubles per square meterб depending on the coating type. When making a managerial decision on a paint production, a risk of economic damage should be estimated.
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Schirmer, Ulrike, and Andrea Osburg. "Interactions between Non-Ionic Additives and Cement Phases." Advanced Materials Research 1129 (November 2015): 492–99. http://dx.doi.org/10.4028/www.scientific.net/amr.1129.492.
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For a variety of applications the use of polymer modified cement mortar (PCM) or polymer modified cement concrete (PCC) is state of the art. It is a matter of common knowledge that interparticular interactions between the mineral and polymer components, more precisely the adsorption behaviour and film formation processes of polymer particles, cause a change of properties in comparison to a concrete without any modification. The affinity of polymer particles to mineral surfaces determines the adsorption behaviour significantly and thus the microstructure formation of the entire system, in which mineral and polymer phases penetrate one another. A quantitative prediction of cementitious surface preferred by non-ionic stabilized polymer particles to adsorb, was aspirated by titration experiments carried out with electroacoustic zeta potential measurements and turbidity measurements of polymer modified pastes carried out by spectrophotometry. Measuring the change of zeta potential of several cementitious components by a stepwise addition of polymer dispersions, do not require a variation of variables of the system. It can be measured without any treatment of the powdery raw materials or dissolution of the considered suspension. Equally the polymer dispersions were used in their original state. Spectrophotometric analyses were used to determine the concentration of polymer particles in the liquid phase of fresh polymer modified cement-paste or pastes of additives like quartz powder. The preparation of dilution series allowed the assessment of desorption behaviour as well as the prediction of the amount of adsorbed particles. Finally affinities of non-ionic stabilized polymer particles to several mineral surfaces in a state constituted, fresh paste could be described as a result of chemical induced repulsive or attractive forces and physical repressions, like the absence of sufficient space in liquid media for dispersed polymer particles. The central role of non-ionic stabilizers in adsorption processes was exposed especially by electroacoustic zeta potential measurements.
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Hojczyk, Markus, and Oliver Weichold. "Melt-rheological behavior of high-solid cement-in-polymer dispersions." Journal of Applied Polymer Science 119, no. 1 (July 27, 2010): 565–71. http://dx.doi.org/10.1002/app.32676.
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Kremieniewski, Marcin. "Korelacja skuteczności działania środków dyspergujących o różnym mechanizmie upłynniania." Nafta-Gaz 76, no. 11 (November 2020): 816–26. http://dx.doi.org/10.18668/ng.2020.11.07.
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Effective borehole sealing depends on many properties of the cement slurry. The rheological parameters are the most important. Designing the cement slurry with the required values of plastic viscosity, yield point or consistency coefficient contributes to the efficient performance of the cementing procedure and allows for effective filling of the cemented space outside the tubing. In order to adjust rheological parameters to technological requirements, dispersants are used. The operation of these plasticizers or superplasticizers is related to their chemical structure, which determines their liquefaction mechanism. Therefore, in order to properly select a fluidizing agent, it is beneficial to become familiar with its mechanism of operation, thanks to which it will be possible to use the optimal amounts for a given cement slurry recipe. The publication discusses the effectiveness of dispersing agents depending on their liquefaction mechanism. The research work carried out consisted in the modification of the cement slurry with the use of sodium salts of polycondensates of naphthalene sulfonic acids and a polymer dispersant based on carboxylates. Amounts of dispersant ranging from 0.05% (bwoc) to 1.0% (bwoc) were used. The rheological parameters described by means of five rheological models, i.e. Newton, Bingham, Ostwald de Waele, Casson and Herschele-Bulkley, were tested for the cement slurries. The main goal of the work presented in the article was to conduct a correlation analysis of the change in rheological parameters of slurries modified with dispersants belonging to different groups depending on their liquefaction mechanism. Thanks to this, it was possible to indicate the effectiveness of the dispersing additives depending on the amount of the fluid used belonging to a specific group. The work carried out is helpful in determining the optimal amount of dispersing agent depending on its type (mechanism of action).