scholarly journals Effects of Surfactants on the Properties of Mortar Containing Styrene/Methacrylate Superplasticizer

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
El-Sayed Negim ◽  
Latipa Kozhamzharova ◽  
Jamal Khatib ◽  
Lyazzat Bekbayeva ◽  
Craig Williams
Keyword(s):  
Mechanical Properties ◽  
Glycidyl Methacrylate ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Monomethyl Ether ◽  
Butyl Methacrylate ◽  
Glycol Monomethyl Ether ◽  
Flow Table ◽  
Polyoxyethylene Glycol ◽  
Polymer Latex

The physical and mechanical properties of mortar containing synthetic cosurfactants as air entraining agent are investigated. The cosurfactants consist of a combination of 2% dodecyl benzene sodium sulfonate (DBSS) and either 1.5% polyvinyl alcohol (PVA) or 1.5% polyoxyethylene glycol monomethyl ether (POE). Also these cosurfactants were used to prepare copolymers latex: styrene/butyl methacrylate (St/BuMA), styrene/methyl methacrylate (St/MMA), and styrene/glycidyl methacrylate (St/GMA), in order to study their effects on the properties of mortar. The properties of mortar examined included flow table, W/C ratio, setting time, water absorption, compressive strength, and combined water. The results indicate that the latex causes improvement in mortar properties compared with cosurfactants. Also polymer latex containing DBSS/POE is more effective than that containing DBSS/PVA.

scholarly journals Effect of TiO2 Nanoparticles on Physical and Mechanical Properties of Cement at Low Temperatures

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Li Wang ◽  
Hongliang Zhang ◽  
Yang Gao
Keyword(s):  
Mechanical Properties ◽  
Low Temperatures ◽  
Cement Hydration ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Xrd Analysis ◽  
Cementitious Materials ◽  
Strength Test ◽  
Hydration Degree ◽  
Time Test

Low temperature negatively affects the engineering performance of cementitious materials and hinders the construction productivity. Previous studies have already demonstrated that TiO2 nanoparticles can accelerate cement hydration and enhance the strength development of cementitious materials at room temperature. However, the performance of cementitious materials containing TiO2 nanoparticles at low temperatures is still unknown. In this study, specimens were prepared through the replacement of cement with 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, and 5 wt.% TiO2 nanoparticles and cured under temperatures of 0°C, 5°C, 10°C, and 20°C for specific ages. Physical and mechanical properties of the specimens were evaluated through the setting time test, compressive strength test, flexural strength test, hydration degree test, mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) analysis, thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM) in order to examine the performance of cementitious materials with and without TiO2 nanoparticles at various curing temperatures. It was found that low temperature delayed the process of cement hydration while TiO2 nanoparticles had a positive effect on accelerating the cement hydration and reducing the setting time in terms of the results of the setting time test, hydration degree test, and strength test, and the specimen with the addition of 2 wt.% TiO2 nanoparticles showed the superior performance. Refined pore structure in the MIP tests, more mass loss of CH in TGA, intense peak appearance associated with the hydration products in XRD analysis, and denser microstructure in SEM demonstrated that the specimen with 2 wt.% TiO2 nanoparticles exhibited preferable physical and mechanical properties compared with that without TiO2 nanoparticles under various curing temperatures.

Properties of Natural Rubber Nanocomposites Reinforced with Carbon Nanotubes

2015 ◽  
Vol 1109 ◽  
pp. 195-199 ◽  
Author(s):  
Abd Aziz Azira ◽  
Dayang Habibah Abangismawi I. Hassim ◽  
D. Verasamy ◽  
Abu Bakar Suriani ◽  
M. Rusop
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Natural Rubber ◽  
Considerable Increase ◽  
Physical And Mechanical Properties ◽  
Rubber Matrix ◽  
Rubber Composites ◽  
Transmission Electron ◽  
Maximum Conductivity ◽  
Polymer Latex

In order to achieve improvements in the performance of rubber materials, the development of carbon nanotube (CNT)-reinforced rubber composites was attempted. The CNT/epoxidised natural rubber (ENR) nanocomposite was prepared through latex technology. Physical and mechanical properties of the CNT/ENR nanocomposites were characterized in contrast to the carbon black (CB)/ENR composite. The dispersion of the CNTs in the rubber matrix and interfacial bonding between them were rather good; monitored transmission electron microscopy and scanning electron microscopy. The mechanical properties of the CNT-reinforced ENR showed a considerable increase compared to the neat ENR and traditional CB/ENR composite. The storage modulus of the CNT/ENR nanocomposites greatly exceeds that of neat ENR and CB/ENR composites and a maximum conductivity of about 1 S m-1 can be achieved. The approach presented can be adapted to other CNT/polymer latex systems.

scholarly journals Antibacterial Effect and Physical-Mechanical Properties of Temporary Restorative Material Containing Antibacterial Agents

2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
Amanda Mahammad Mushashe ◽  
Carla Castiglia Gonzaga ◽  
Paulo Henrique Tomazinho ◽  
Leonardo Fernandes da Cunha ◽  
Denise Piotto Leonardi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compression Strength ◽  
Water Sorption ◽  
Antibacterial Agents ◽  
Antibacterial Effect ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Diffusion Method ◽  
Restorative Material ◽  
Significant Difference

Introduction. For the maintenance of the aseptic chain created during the treatment the coronal sealing becomes paramount. Aim. Evaluating the antibacterial effect and the physical-mechanical properties of a temporary restorative material containing different antibacterial agents. Material and Methods. Two antibacterial agents (triclosan and chloramine T) were manually added to a temporary restorative material used as base (Coltosol). The antibacterial action of the material was analyzed using the agar diffusion method, in pure cultures of Escherichia coli (ATCC BAA-2336) and Staphylococcus aureus (ATCC 11632) and mixed culture of saliva collection. The microleakage rate was analyzed using bovine teeth, previously restored with the materials, and submitted to thermocycling, in a solution of 0.5% methylene blue, for a period of 24 hours. The physical and mechanical properties of the materials analyzed were setting time, water sorption, solubility, and compression strength. Results. No marginal leakage was observed for all groups. There was no statistical significant difference in antimicrobial activity, setting time, water sorption, solubility, and compression strength among the materials. Conclusion. The addition of antibacterial agents on a temporary restorative material did not optimize the antibacterial ability of the material and also did not change its physical-mechanical properties.

scholarly journals Effect of fly ash on physical and mechanical properties of mortar

2019 ◽  
Vol 17 (6) ◽  
pp. 35
Author(s):  
Vu-An Tran
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Water Absorption ◽  
Thermal Power ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Flow Density ◽  
Control Specimen

This research investigates the physical and mechanical properties of mortar incorporating fly ash (FA), which is by-product of Duyen Hai thermal power plant. Six mixtures of mortar are produced with FA at level of 0%, 10%, 20%, 30%, 40%, and 50% (by volume) as cement replacement and at water-to-binder (W/B) of 0.5. The flow, density, compressive strength, flexural strength, and water absorption tests are made under relevant standard in this study. The results have shown that the higher FA content increases the flow of mortar but significantly decreases the density of mixtures. The water absorption and setting time increases as the samples incorporating FA. Compressive strength of specimen with 10% FA is approximately equal to control specimen at the 91-day age. The flexural strength of specimen ranges from 7.97 MPa to 8.94 MPa at the 91-day age with the best result for samples containing 10% and 20% FA.

scholarly journals Self-Compacting Concrete and Concreting Technology for Foundation Block Using 9000 Cubic Meters of Concrete

2021 ◽  
Vol 20 (4) ◽  
pp. 329-337
Author(s):  
E. I. Batyanovskiy ◽  
A. I. Bondarovich ◽  
N. N. Kalinovskaya ◽  
P. V. Ryabchikov
Keyword(s):  
Mechanical Properties ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Test Methods ◽  
Third Party ◽  
Hardened Concrete ◽  
Self Compacting Concrete ◽  
Foundation Slab ◽  
Concrete Mixtures ◽  
Structure Height

. The paper presents the results of the development and implementation of the technology of self-compacting heavy structural concrete and the technology of concreting with its use of the largest foundation slab in Belarus (concrete volume ~9100 m3) of a high-rise building at the facility “Construction of a multifunctional complex in Minsk within the boundaries of Filimonova Street – Avenue Nezavisimosty – Makayonka Street”. The results of research are shown, which ensured the production of self-compacting concrete of class C35/45 with water resistance up to W20 (with the required W12 according to the project) from concrete mixtures of the maximum cone expansion of the PK6 (RK6) grade for three zones of the foundation slab different in degree of reinforcement: lower, middle and upper, with a total structure height of 3.5 m and plan dimensions ~(83´34) m. The technology of continuous (seamless) concreting has been developed and implemented, which made it possible to lay ~9100 m3 of concrete into the structure without defects within 42 hours of continuous operation, and a system of technological measures that prevented temperature cracking in concrete. The homogeneity of the physical and mechanical properties of concrete, confirmed by control tests, is ensured due to the uniform supply of the concrete mixture (from six  concrete pumps at the same time) in layers 200–300 mm high with a distance between the supply points of about 5–6 m and the vertical arrangement of the “trunks” of the concrete pipes during delivery of concrete to each point, as well as the fact that the time for feeding the next volume of concrete was significantly less than the setting time of the previously laid concrete (with a total concreting speed £0.1 m/h). Standardized and original test methods for concrete mixtures, hardening kinetics and properties of hardened concrete have been used during the development, research and implementation of the project. Control tests of physical and mechanical properties and characteristics of concrete, carried out at BNTU together with authorized  organizations controlling the progress of construction, as well as in independent (third-party) organizations, have confirmed their compliance with the design requirements.

scholarly journals Experimental Investigation of the Physical and Mechanical Properties of Cassava Starch Modified Concrete

2019 ◽  
Vol 13 (1) ◽  
pp. 331-343 ◽  
Author(s):  
Daniel Oluwabusayo ONI ◽  
John Mwero ◽  
Charles Kabubo
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Setting Time ◽  
Research Work ◽  
Physical And Mechanical Properties ◽  
Cassava Starch ◽  
Split Tensile Strength ◽  
Chemical Admixtures ◽  
Mix Proportion ◽  
Hot Weather

Background: Concrete is a widely used material in construction, which has given rise to innovations in terms of modifying some of its properties to meet desired requirements. The use of chemical admixtures is important in this regard, which has necessitated the search for new materials which can serve as a substitute. Objective: This research work investigates the use of Cassava Starch (CS) as an admixture for improving the physical and mechanical properties of concrete. Methodology: The physical and mechanical properties of concrete were studied by adding CS by weight of cement at 0.4, 0.8, 1.2, 1.6 and 2.0%, respectively. Concrete cubes and cylinders were cast and cured for a test period of 7, 14, 28, 56 and 90 days, respectively. Unreinforced beams of size 150 x 150 x 530 were cast and cured for 28 days. A total of 6 mix proportion was used, five out of which were used to examine the effect of CS on the properties of concrete. Results: The workability of concrete reduced as the percentage of CS increased due to its viscosity modifying properties. CS increased the initial and final setting time of concrete for every increase in percentage addition. An improvement in the compressive strength, split tensile strength, flexural strength and elastic modulus of concrete were noticed for cassava starch-modified concrete over the control for some of the mixes at all days of curing. The density of concrete was found to decrease at 1.6 and 2.0% addition of CS in concrete. Conclusion: From the results of this investigation, CS improved the compressive, split tensile, flexural and elastic modulus of concrete at an optimum of 0.8 percentage addition of CS. The setting time of concrete was also increased, which makes CS suitable to be used as a retarding admixture in hot weather concreting. Based on the findings of the work, CS can be considered as an admixture to be used as a substitute for retarders and viscosity modifying admixtures for improved concrete properties.

Influence of the Chemical Composition of Bauxite on Mineral Formation and Properties of Sulfoaluminate-Ferrite Cement

2021 ◽  
Vol 325 ◽  
pp. 53-58
Author(s):  
Aleksandr A. Ponomarenko ◽  
Fedor L. Kapustin ◽  
Elena Makarova ◽  
Ekaterina S. Gerasimova
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Sulfur Dioxide ◽  
Specific Surface ◽  
Mineral Composition ◽  
Cement Paste ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Mineral Formation ◽  
Quality Coefficient

The influence of the chemical composition of bauxite on the mineral formation and structure of sulfoaluminate-ferrite clinker (SAFC), and physical and mechanical properties of cement based on it is studied. Ferrous bauxite, marble crushing screenings and neutralized fluorine-anhydrite were used for the synthesis of SAFC. The compositions of raw mixes of low-and high-alkaline SAFC are calculated with modular characteristics: Mf (ferritic modulus) = 0.35 and 0.7, Мs (sulfate modulus) = 0.167 and 0.5, respectively. Clinker synthesis from a raw mix containing ferrous bauxite with a quality coefficient of 1.7 must be carried out at a temperature of 1250 °C, which is reduced to 1200 °C for burning a raw mix based on bauxite with a quality coefficient of 2.2. Intensive decomposition of anhydrite occurs with the release of sulfur dioxide into the atmosphere at a temperature of 1300 °C, so it is not recommended to burn SAFC at this temperature. The mineral composition of the obtained SAFC is represented by sulfoaluminate, calcium sulfoferrite and free anhydrite. There is no C2S as a separate phase in clinkers, since in the process of their synthesis belite dissolves in 3С(A,F)·СŜ, mainly in the aluminoferrite phase. The use of bauxite with a quality coefficient of 2.2 in the SAFC raw mix increases the cement activity up to 54.2 MPa. Increasing its specific surface from 350 to 460 m2/kg significantly reduces the setting time of cement paste and increases the strength of sulfoaluminate-ferrite cement both in the early (up to 43.4 MPa) and late hardening periods (up to 67.3 MPa).

scholarly journals Acrylic Bone Cements Modified with Graphene Oxide: Mechanical, Physical, and Antibacterial Properties

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1773 ◽  
Author(s):  
Mayra Eliana Valencia Zapata ◽  
Lina Marcela Ruiz Rojas ◽  
José Herminsul Mina Hernández ◽  
Johannes Delgado-Ospina ◽  
Carlos David Grande Tovar
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Bacterial Infections ◽  
Setting Time ◽  
Antibacterial Properties ◽  
Physical And Mechanical Properties ◽  
Maximum Temperature ◽  
Bone Cements ◽  
Gram Negative ◽  
Total Joint Replacements

Bacterial infections are a common complication after total joint replacements (TJRs), the treatment of which is usually based on the application of antibiotic-loaded cements; however, owing to the increase in antibiotic-resistant microorganisms, the possibility of studying new antibacterial agents in acrylic bone cements (ABCs) is open. In this study, the antibacterial effect of formulations of ABCs loaded with graphene oxide (GO) between 0 and 0.5 wt.% was evaluated against Gram-positive bacteria: Bacillus cereus and Staphylococcus aureus, and Gram-negative ones: Salmonella enterica and Escherichia coli. It was found that the effect of GO was dependent on the concentration and type of bacteria: GO loadings ≥0.2 wt.% presented total inhibition of Gram-negative bacteria, while GO loadings ≥0.3 wt.% was necessary to achieve the same effect with Gram-positives bacteria. Additionally, the evaluation of some physical and mechanical properties showed that the presence of GO in cement formulations increased wettability by 17%, reduced maximum temperature during polymerization by 19%, increased setting time by 40%, and increased compressive and flexural mechanical properties by up to 17%, all of which are desirable behaviors in ABCs. The formulation of ABC loading with 0.3 wt.% GO showed great potential for use as a bone cement with antibacterial properties.

scholarly journals Retarding effect of grinding dust and its influence on the physical-mechanical and rheological properties of cementitious matrices

2019 ◽  
Vol 12 (3) ◽  
pp. 486-508
Author(s):  
R. D. MARIANO ◽  
J. S. ANDRADE NETO ◽  
M. R. MORELLI ◽  
D. V. RIBEIRO
Keyword(s):  
Mechanical Properties ◽  
Rheological Properties ◽  
Setting Time ◽  
Squeeze Flow ◽  
Retarding Effect ◽  
Finishing Process ◽  
Flow Table ◽  
Hardened State

Abstract The present study evaluated the feasibility of the use of grinding dust (GD), a waste generated in the clutch disc finishing process, as a retardant additive in cementitious matrices. For this, the waste was added in contents of 5%, 10% and 15%, relative to the cement weight, and the setting time was determined by the Vicat method. In addition, the influence of this material on rheology (flow table, squeeze-flow and rotational rheometry) and on the physical-mechanical properties of the hardened matrices was analyzed. The results indicated an increase in setting time and a reduction in the fluidity of the mortars as a function of the addition of GD and the best results for the hardened state properties were verified for the cementitious matrices containing a 5% addition. Therefore, it was observed that GD is effective in retarding the setting time, presenting great potential for use in civil construction, without impairing its properties.

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