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.

Effect of Wood Filler Concentration on Physical and Mechanical Properties of PLA-Based Composites

2021 ◽  
Vol 887 ◽  
pp. 110-115
Author(s):  
G.A. Sabirova ◽  
R.R. Safin ◽  
N.R. Galyavetdinov
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Composite Materials ◽  
Impact Strength ◽  
Wood Flour ◽  
Experimental Studies ◽  
Physical And Mechanical Properties ◽  
Filler Concentration ◽  
High Concentration

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.

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.

Comparative experimental study on physical and mechanical properties of quartz sandstone after water-cooling and natural-cooling under high temperature

2021 ◽  
pp. qjegh2020-181
Author(s):  
Haopeng Jiang ◽  
Annan Jiang ◽  
Fengrui Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Uniaxial Compressive Strength ◽  
Heating Temperature ◽  
Physical And Mechanical Properties ◽  
P Wave ◽  
Water Cooling ◽  
Average Value ◽  
Cooling Methods

Experimental tests were conducted to study the influence of natural cooling and water cooling on the physical and mechanical properties of quartz sandstone. This study aims to understand the effect of different cooling methods on the physical and mechanical properties of quartz sandstone (such as mass, volume, density, P-wave velocity, elastic modulus, uniaxial compressive strength, etc.). The results show that the uniaxial compressive strength (UCS) and elastic modulus(E) of the specimens cooled by natural-cooling and water-cooling decrease with heating temperature. At 800℃, after natural cooling and water cooling, the average value of UCS decreased by 34.65% and 57.90%, and the average value of E decreased by 87.66% and 89.05%, respectively. Meanwhile, scanning electron microscope (SEM) images were used to capture the development of microcracks and pores within the specimens after natural-cooling and water-cooling, and it was found that at the same temperature, water cooling treatment was more likely to cause microcracks and pores, which can cause more serious damage to the quartz sandstone. These results confirm that different cooling methods have different effects on the physical and mechanical properties of quartz sandstone, and provide a basis for the stability prediction of rock mass engineering such as tunnel suffering from fire.

scholarly journals Effects of High Temperatures on the Physical and Mechanical Properties of Carbonated Ordinary Concrete

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Qifang Xie ◽  
Lipeng Zhang ◽  
Shenghua Yin ◽  
Baozhuang Zhang ◽  
Yaopeng Wu
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Elastic Modulus ◽  
High Temperatures ◽  
Elevated Temperatures ◽  
Physical And Mechanical Properties ◽  
Surface Characteristics ◽  
Time Service ◽  
Different Temperatures ◽  
Cooling Methods

Fires are always known for seriously deteriorating concrete in structures, especially for those with certain carbonation due to long-time service. In this paper, 75 prism specimens were prepared and divided into four groups (three carbonated groups and one uncarbonated group). Specimens were tested under different temperatures (20, 300, 400, 500, 600, and 700°C), exposure times (3, 4, and 6 hours), and cooling methods (water and natural cooling). Surface characteristics, weight loss rate, and residual mechanical properties (strength, initial elastic modulus, peak, and ultimate compressive strains) of carbonated concrete specimens after elevated temperatures were investigated and compared with that of the uncarbonated ones. Results show that the weight loss rates of the carbonated concrete specimens are slightly lower than that of the uncarbonated ones and that the cracks are increased with raising of temperatures. Surface colors of carbonated concrete are significantly changed, but they are not sensitive to cooling methods. Surface cracks can be evidently observed on carbonated specimens when temperature reaches 400°C. Residual compressive strength and initial elastic modulus of carbonated concrete after natural cooling are generally larger than those cooled by water. The peak and ultimate compressive strains of both carbonated and uncarbonated concrete specimens increase after heating, but the values of the latter are greater than that of the former. Finally, the constitutive equation to predict the compressive behaviors of carbonated concrete after high temperatures was established and validated by tests.

The Effect of Lithium Alumina Silicate Phases on Elastic Modulus of Porcelain Tiles

2014 ◽  
Vol 92 ◽  
pp. 188-193 ◽  
Author(s):  
Tuna Aydin ◽  
Alpagut Kara
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Liquid Phase ◽  
Bulk Density ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Raw Material ◽  
Closed Porosity ◽  
Low Viscosity ◽  
Porcelain Tiles

Spodumene, which is a lithium alumina silicate, has been used as a raw material in the production of thermal shock resistant whitewares and sanitarywares. The presence of spodumene results in enhancement of mullitization and imparts better physical and mechanical properties to ceramics. In this study, the influence of Lithium alumina silicate phases on the mechanical properties of standard porcelain stoneware body was investigated. Especially solid-solid reactions were observed between spodumene and quartz or spodumene and clay. These solid-solid reactions bring about a newly formed lithium alumina silicate (LAS) phases. Spodumene allows the development of a low viscosity liquid phase and results in a decrease in closed porosity, also with increase in bulk density, bending strength and elastic modulus.

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.

Effect of Hardening Accelerators and other Chemical Admixtures on the Properties of a Quick-Setting Mixture

2018 ◽  
Vol 276 ◽  
pp. 116-121 ◽  
Author(s):  
Alsu Khamatova ◽  
Grigory Ivanovich Yakovlev ◽  
Vadim Khozin ◽  
Grigory Nikolaevich Pervushin
Keyword(s):  
Mechanical Properties ◽  
Setting Time ◽  
Physicomechanical Properties ◽  
Electric Steelmaking ◽  
Steelmaking Slag ◽  
Strength Gain ◽  
Short Term ◽  
Fine Grained ◽  
Chemical Admixtures ◽  
Gypsum Content

The physicochemical and physicomechanical properties of quick-setting compositions based on fine-grained electric steelmaking slag (ESS) produced by Izhstal PJSC, Russia, have been examined. The study also focuses on the processes of interaction of the components of the compositions based on ESS in combination with hardening accelerators (Li2CO3, K2SO4) and plasticizing additives (SP-1, Melflux 2651F). It has been found that mechanoactivation of the composition improves the hydration in comparison with chemical admixtures. This can be proved by the obtained results of the setting and testing timing of the mechanical properties of the mixture. Plasticizers being added, the setting time increases at the average by 2.3 times, and accelerators being added, by 2 times compared with the mechanically activated composition. The influence of mechanoactivation on the strength of the compositions has been described. In comparison with the plasticized composition, the strength increases by 10%, while using accelerators – by 30%. Thus, the most effective way of producing a dry mixture with the properties of quick setting and hardening is a short-term mixed grinding of all its components, which makes it possible to exclude accelerating chemical admixtures and plasticizing additives in the mixture. Also, grinding positively affects the strength gain of quick-setting compositions while reducing the gypsum content to 5%.

Physical Properties of Volcanic Ash Based Geopolymer Concrete

2016 ◽  
Vol 841 ◽  
pp. 1-6 ◽  
Author(s):  
Puput Risdanareni ◽  
Adjib Karjanto ◽  
Febriano Khakim
Keyword(s):  
Tensile Strength ◽  
Fly Ash ◽  
Physical Properties ◽  
Volcanic Ash ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Ash Content ◽  
Geopolymer Concrete ◽  
Split Tensile Strength ◽  
Time Test

This paper describes the result of investigating volcanic ash of Mount Kelud as fly ash substitute material to produce geopolymer concrete. The test was held on geopolymer concrete blended with 0%, 25%, 50% and 100% fly ash replacement with volcanic ash. Natrium Hidroxide (NaOH) with concentration of 12 molar and Natrium Silicate (Na2SiO3) were used as alkaline activator. While alkali-activator ratio of 2 was used in this research. The physical properties was tested by porosity and setting time test, while split tensile strength presented to measure brittle caracteristic of geopolymer concrete. The result shown that increasing volcanic ash content in the mixture will increase setting time of geopolymer paste. On the other hand increasing volcanic ash content will reduce split tensile strength and porosity of geopolymer concrete. After all replacing fly ash with volcanic ash was suitable from 25% to 50% due to its optimum physical and mechanical properties.

Production of mullite‒TiC‒с-BN‒с-ZrO2-materials by the method of plasma-spark sintering and their properties

2019 ◽  
pp. 23-29 ◽  
Author(s):  
A. V. Hmelov
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Elastic Modulus ◽  
Linear Correlation ◽  
Modulus Of Elasticity ◽  
Physical And Mechanical Properties ◽  
Linear Shrinkage ◽  
Physicomechanical Properties ◽  
Intensive Development ◽  
Crystalline Microstructure

The effect of different с-BN and с-ZrO2 ratios on the phase composition, microstructure, relative density, open porosity, linear shrinkage, physicomechanical properties, and linear correlation of the elastic modulus and toughness of samples during plasma-spark sintering at pressing load 70 MPa in the range of 1200‒1600 °C is shown. The synthesized powders of TiC, c-BN and c-ZrO2, sintered at 1400 °C by the plasma-spark method, are characterized by intense crystallization of the phases. Sintered samples with different ratios of c-BN and c-ZrO2 show the intensive development of mullite and TiC. An increase in the c-BN / c-ZrO2 ratio promotes an active increase in c-BN and a less intensive increase in с-ZrO2 in the range of 1200‒1600 °C, and it causes the formation of a less uniform and densely sintered crystalline microstructure with a large number of pores at 1500 °C. This sample has lower values of physical and mechanical properties and a lower linear correlation of the modulus of elasticity and toughness in the range of 1200‒1600 °C and lower crack resistance at 1500 °C. Ill. 9. Ref. 13. Tab. 1.

Correlation of the Coefficient of Adhesion With Various Physical and Mechanical Properties of Metals

1963 ◽  
Vol 85 (2) ◽  
pp. 279-285 ◽  
Author(s):  
M. E. Sikorski
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Elastic Modulus ◽  
Surface Energy ◽  
Work Hardening ◽  
Physical And Mechanical Properties ◽  
Atomic Volume ◽  
Recrystallization Temperature ◽  
Bonding Method

The coefficients of adhesion determined by a modification of the twist-compression bonding method are compared with the following properties of metals: crystal structure, hardness, surface energy, elastic modulus, work-hardening properties, recrystallization temperature, purity, and atomic volume. Conclusions are reached regarding the desirable characteristics of metals, or combinations of metals, for antifriction applications.

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