Influence of Nanosized Silica Component on Physical and Mechanical Properties of a Composite Gypsum Binder

2014 ◽  
Vol 584-586 ◽  
pp. 1756-1760 ◽  
Author(s):  
Elena Valerievna Voitovich ◽  
Alla Vasilievna Cherevatova ◽  
Igor Vladimirovich Zhernovsky ◽  
Hans Bertram Fischer ◽  
Valeria Valerievna Strokova ◽  
...  

The work presents the results of development of the composite gypsum binder (GB) with nanostructured binder on the basis of silica component (NBC). Introduction of NBC changes the kinetics of hardening, as well as improves physical and mechanical properties of gypsum system. Analysis of the microstructure of the GB has demonstrated in the presence of the NB the size and morphology of crystals are changed, promoting the formation of fine-crystalline structure and increase the contact area between new formations, compared to NBC – free gypsum system. Experimental studies have shown that the mechanical properties of the composite gypsum application of NBC increased, reduced water absorption, density increases, and increases the setting time.

2021 ◽  
Vol 887 ◽  
pp. 110-115
Author(s):  
G.A. Sabirova ◽  
R.R. Safin ◽  
N.R. Galyavetdinov

This paper presents the findings of experimental studies of the physical and mechanical properties of wood-filled composites based on polylactide (PLA) and vegetable filler in the form of wood flour (WF) thermally modified at 200-240 °C. It also reveals the dependence of the tensile strength, impact strength, bending elastic modulus, and density of composites on the amount of wood filler and the temperature of its thermal pre-modification. We established that an increase in the concentration of the introduced filler and the degree of its heat treatment results in a decrease of the tensile strength, impact strength and density of composite materials, while with a lower binder content, thermal modification at 200 °C has a positive effect on bending elastic modulus. We also found that 40 % content of a wood filler heated to 200 °C is sufficient to maintain relatively high physical and mechanical properties of composite materials. With a higher content of a wood filler, the cost can be reduced but the quality of products made of this material may significantly deteriorate. However, depending on the application and the life cycle of this product, it is possible to develop a formulation that includes a high concentration of filler.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Li Wang ◽  
Hongliang Zhang ◽  
Yang Gao

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.


2020 ◽  
pp. 451-457
Author(s):  
Aleksandr Yur'yevich Vititnev ◽  
Yuriy Davydovich Alashkevich ◽  
Natal'ya Geral'dovna Chistova ◽  
Roman Aleksandrovich Marchenko ◽  
Venera Nurullovna Matygullina

This paper presents the results of experimental studies of the physical and mechanical properties of wood-fiber boards of the wet production method when regulating the design and technological parameters of the grinding process. This allowed us to determine the influence of the working clearance between the grinding discs and the concentration of fibre mass with the subject to of quality change wood fiber after defibrator using the developed construction of the disc fibrillation action on the physico-mechanical properties of boards. As a result of the experiment, regression models were obtained that adequately describe the studied grinding process and allow predicting the values of physical and mechanical properties of the finished product depending on the established  parameters process. A comparative analysis of the size and quality characteristics of the fiber semi-finished product and its fractional composition when using a developed construction the disc of refiner fibrillation action and a traditional design used in industry is carried out. The preferential efficiency of the grinding process under the fibrillating effect the disc of refiner in comparison with the traditional construction disc of refiner is established. As a result, there is a significant improvement in the quality indicators of the fiber semi-finished product and its composition due to the formation and predominance in the total mass of long and thin, respectively, flexible fibrillated fibers with high tile-forming properties, which allows to increase the strength properties of the product (by 20–25%), without using binding resins.


This chapter discusses the effects of metakaolin (MK) on geopolymer mortar and concrete industries. The research topics of MK-based geopolymer cover reaction mechanisms and kinetics. This chapter aims at augmenting knowledge about enhancing mechanical properties of geopolymer mortars/concrete using MK. Specifically, this chapter presents literature studies as well as current experimental studies which delineate the effect of MK on fresh and hardened-state properties of geopolymer mortars (GPMs). Properties and characteristics of metakaolin are explained followed by properties of fresh MK mortars. Properties of hardened MK concrete and durability aspects of MK mortars are explained. Applications of MK-based geopolymers and metakaolin-based geopolymers as repair materials are also included in this chapter. The results of using MK-based GPMs revealed improved workability, enhanced setting time, increased density, higher compressive strength, flexural strength, and resistance against acid attack than conventional ordinary portland cement mortar/concrete.


2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
Amanda Mahammad Mushashe ◽  
Carla Castiglia Gonzaga ◽  
Paulo Henrique Tomazinho ◽  
Leonardo Fernandes da Cunha ◽  
Denise Piotto Leonardi ◽  
...  

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.


2019 ◽  
Vol 974 ◽  
pp. 181-186
Author(s):  
V.A. Perfilov ◽  
V.V. Gabova ◽  
Inessa A. Tomareva

The effect of superplasticizing, foam agents, various fiber aggregates on the physical and mechanical properties of cellular concrete has been studied. The article covers the results of experimental studies conducted to determine the effect of foam agents PO-6 and PB-2000, as well as polymeric and basalt fiber on the pore structure of foam concrete. The dependence between the change in density and strength of cellular concrete and the structure of its pore space has been determined.


Author(s):  
Хафизов ◽  
Kamil Khafizov ◽  
Хафизов ◽  
Ramil Khafizov

A similarity criteria were reveled to determine the dependence of maximum pressure of the tractor wheel on the soil on the basis of the use of similarity theory. Each similarity criterion includes several parameters, characterizing the tractor, its propeller and physical and mechanical properties of the soil. The similarity criteria is taken as factors in the multivariate experiment. Multifactorial experimental studies were planned and carried out. We used Statistics Toolbox subsystem of Matlab computer mathematics system for processing the results of experiments. As a result of statistical processing of the experimental data by the equation we obtained a dependence of maximum pressure of the tractor wheel on the soil from tractor parameters, and physical and mechanical properties of the soil. Statistical data on the equations, such as - multiple correlation coefficient, Fisher’s criterion, Student’s criterion, indicate the significance of equations of the experiments variants, as well as the significance of the coefficients of the regression equations.


Author(s):  
Vu-An Tran

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.


Author(s):  
N. I. Chaban

Research of new methods and technologies of non-destructive control of change of long-term metal structures is an actual task of the present. In this article the methodology and results of experimental studies, the main aim of which is to determine the correlation between the intensity of structural noise in the material determined by failure detectors based on ultrasonic field-induced phase grating and the physical and mechanical properties of steels are presented.


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