scholarly journals Effects of load types and critical molar ratios on strength properties and geopolymerization mechanism

2021 ◽  
Vol 60 (1) ◽  
pp. 216-222
Author(s):  
Tao Meng ◽  
Sara Ahmed ◽  
Dawang Dai ◽  
Yue Yu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Bending Strength ◽  
Strength Properties ◽  
Degree Of Polymerization ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Loading Patterns ◽  
Load Types ◽  
The Relationship

Abstract In this study, the effect of SiO2/Al2O3 (S/A), Na2O/Al2O3 (N/A) and H2O/Na2O (H/N) molar ratios on bending and compressive strength of geopolymer were investigated. The geopolymerization mechanism was also analyzed from microstructure difference by FTIR. The experimental results showed that compressive strength and bending strength of geopolymer has an opposite reaction under different critical molar ratios. The increase of S/A molar ratio and the decrease of N/A and H/N molar ratios have resulted in an increase of the compressive strength. However, it caused a noticeable decrease in bending strength. The microstructure of geopolymer indicated that the degree of polymerization and cohesion of geopolymer have systematical depending on these critical molar ratios, making the mechanical properties of geopolymer susceptible to different types of loads. This paper reveals the relationship between the microstructure of geopolymer and different mechanical properties and helps to selectively prepare corresponding geopolymer for different loading patterns.

scholarly journals AN INVESTIGATION ON THE EFFECTS OF MICRO-PARAMETERS ON THE STRENGTH PROPERTIES OF ROCK

2021 ◽  
Vol 36 (1) ◽  
pp. 111-119
Author(s):  
Behzad Jafari Mohammadabadi ◽  
Kourosh Shahriar ◽  
Hossein Jalalifar ◽  
Kaveh Ahangari
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Friction Coefficient ◽  
Critical Stress ◽  
Friction Angle ◽  
Strength Properties ◽  
Brazilian Tensile Strength ◽  
The Relationship

Rocks are formed from particles and the interaction between those particles controls the behaviour of a rock’s mechanical properties. Since it is very important to conduct extensive studies about the relationship between the micro-parameters and macro-parameters of rock, this paper investigates the effects of some micro-parameters on strength properties and the behaviour of cracks in rock. This is carried out by using numerical simulation of an extensive series of Uniaxial Compressive Strength (UCS) and Brazilian Tensile Strength (BTS) tests. The micro-parameters included the particles’ contact modulus, the contact stiff ness ratio, bond cohesion, bond tensile strength, the friction coefficient and the friction angle, and the mechanical properties of chromite rock have been considered as base values of the investigation. Based on the obtained results, it was found that the most important micro-parameters on the behaviour of rock in the compressive state are bond cohesion, bond tensile strength, and the friction coefficient. Also, the bond tensile strength showed the largest effect under tensile conditions. The micro-parameter of bond tensile strength increased the rock tensile strength (up to 5 times), minimized destructive cracks and increased the corresponding strain (almost 2.5 times) during critical stress.

scholarly journals Effect of Fiber Reinforcement on the Compression and Flexural Strength of Fiber-Reinforced Geopolymers

2021 ◽  
Vol 11 (21) ◽  
pp. 10443
Author(s):  
Michał Łach ◽  
Bartłomiej Kluska ◽  
Damian Janus ◽  
Dawid Kabat ◽  
Kinga Pławecka ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Building Materials ◽  
Bending Strength ◽  
Strength Properties ◽  
Attractive Alternative ◽  
Reinforcing Fibers ◽  
Different Types ◽  
The Matrix ◽  
Glass Carbon

This work aimed to determine the effect of the addition of different types of reinforcing fibers on the strength properties of geopolymers such as flexural and compressive strength. Geopolymers are an attractive alternative to conventional binders and building materials; however, one of the main problems of their widespread use is their low resistance to brittle fracture. To improve the mechanical properties, reinforcement in the form of glass, carbon, and basalt fibers (as grids) was applied to geopolymers in the following work. Additionally, composites with these fibers were produced not only in the matrix of pure geopolymer but also as a hybrid variant with the addition of cement. Furthermore, basalt grids were used as reinforcement for geopolymers not only based on ash but also metakaolin. An additional variable used in the study was the molar concentration of the alkali solution (5 M and 10 M) for the different types of geopolymer samples. The mechanical properties of geopolymer materials and geopolymer–cement hybrids are the highest when reinforcement in the form of carbon fiber is used. Strength values for geopolymers reinforced with basalt mats depend on the number of reinforcement layers and the concentration of the alkaline solution used. All produced composites were tested for compressive strength and bending strength. When using basalt mesh, it was possible to achieve a bending strength of 12 MPa. The highest compressive strength that was achieved was the value of 66 MPa, while for samples not reinforced with fibers, only about 40 MPa was achieved.

Size Effect on Mechanical Properties of LVL

2014 ◽  
Vol 887-888 ◽  
pp. 824-829
Author(s):  
Qing Fang Lv ◽  
Ji Hong Qin ◽  
Ran Zhu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Size Effect ◽  
Tensile Test ◽  
Compression Test ◽  
Test Results ◽  
Laminated Veneer Lumber ◽  
Object Of Study ◽  
The Relationship

Laminated veneer lumber is taken as an object of study, and use LVL specimens of different sizes for compression test and tensile test. The goal of the experiment is to investigate the size effect on compressive strength and tensile strength as well as the influence of the secondary glued laminated face, which appears in the secondary molding processes. The results show that both compressive strength and tensile strength have the size effect apparently and the existence of the secondary glued laminated face lower the compressive strength of LVL specimens. Afterwards, the relationship between compressive strength and volume along with tensile strength and area are obtained by the test results.

Strength Properties of Activated Hwangtoh Mortars

2010 ◽  
Vol 168-170 ◽  
pp. 709-715
Author(s):  
Dongsik Oh ◽  
Doheom Song ◽  
Seongseok Go
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Building Materials ◽  
Strength Properties ◽  
Mixing Conditions ◽  
Substitution Ratio ◽  
Pozzolanic Properties ◽  
The Relationship ◽  
Furnace Slag

Hwangtoh (loess) has pozzolanic properties that mean it can be used as a cement admixture when activated at high temperatures, and that it can be used in combination with building materials such as fly ash or blast furnace slag. This study aimed to analyze the relationship between the compressive strength and the brick bond strength of various mortars containing hwangtoh, and also to find the optimum mixing conditions for the use of hwangtoh. It was found that the mortars’ strength properties are significantly influenced by the water/cement ratio W/C and the activated hwangtoh substitution ratio. We recommend the following materials and mixing conditions: W/C 60%, a cement substitution ratio of activated hwangtoh of 20 ~ 25%, and the addition of 10% blast furnace slag to improve the compressive strength of such mortars.

scholarly journals The Effect of Borax Solution as Preservative to the Mechanical Properties of Bamboo

2020 ◽  
Vol 11 (2) ◽  
Author(s):  
M.A.P Handana ◽  
◽  
Besman Surbakti ◽  
Rahmi Karolina ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Bending Strength ◽  
Environmentally Friendly ◽  
Preservative Solution ◽  
Borax Solution ◽  
Preservative Solutions

The use of borax solution as a preservative in wood and bamboo materials is well known in the community. A borax solution is an environmentally friendly liquid that can dissolve in water, so it is suitable to be used as a preservative within cold or hot soaking techniques. The ability of borax to resist insects and fungus attacks on bamboo has been proven, but the effect of the solution on the strength of bamboo must also be investigated. This study conducts to investigate the effects of borax and its additives as preservative solutions to the mechanical properties of bamboos. The bamboos preservations were conducted by cold conditions of immersion, while the mechanical properties were performed to understand the effects of preservatives. The result of this study indicated that 30% to 50% borax in the preservative solution is sufficient to provide significant increase in strength for compressive strength, tensile strength, and bending strength of bamboo specimen. From this study, the use of borax solution in preserving the bamboos materials improved the quality of bamboos based on its mechanical properties.

Modeling the influence of chemical composition on compressive strength behavior of alkali-activated phosphorus slag cement using statistical design

2018 ◽  
Vol 45 (12) ◽  
pp. 1073-1083 ◽  
Author(s):  
Hamideh Mehdizadeh ◽  
Ebrahim Najafi Kani
Keyword(s):  
Compressive Strength ◽  
Chemical Composition ◽  
Statistical Design ◽  
Molar Ratio ◽  
Statistical Experimental Design ◽  
Molar Ratios ◽  
Strength Behavior ◽  
Optimum Chemical Composition ◽  
Optimum Chemical ◽  
Alkali Activated

In this study, a statistical experimental design based on response surface methodology (RSM) has been applied to predict and optimize the compressive strength of alkali-activated phosphorus slag in different ages (3, 7, and 28 days). For this purpose, the binder samples were prepared with different molar ratios of SiO2/Na2O (S/N), Na2O/Al2O3(Na/Al), and H2O/Al2O3(H/Al) as alkali activator. Results showed that S/N molar ratio plays its role in early ages of curing and Na/Al molar ratio, and showed its significant effect on 7 and 28 days of compressive strength. H/Al molar ratio had the most significant effect on compressive strength compared to the other parameters. The derived RSM models were statistically adequate and could be used to predict the compressive strength. The optimum chemical composition of activator to obtain the highest compressive strength was achieved as 0.39, 1.34, and 30 for S/N, Na/Al, and H/Al molar ratios, respectively, with compressive strength of 30, 65, and 100 MPa at 3, 7, and 28 days of curing.

Influence of the Method of Polymerization of Composite Material for Teeth Crown Fillings on its Strength Properties

2015 ◽  
Vol 240 ◽  
pp. 168-173
Author(s):  
Grzegorz Milewski ◽  
Tomasz Majewski
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Composite Material ◽  
Modulus Of Elasticity ◽  
Strength Properties ◽  
Dental Practice ◽  
Polymerization Shrinkage ◽  
Filling Materials

Polymerization shrinkage of composite filling materials still becomes one of the most important features which decreases strength properties of reconstructed teeth crowns. From among various methods to reduce that disadvantageous phenomenon which are used in a dental practice sandwich filling processing of crown cavity seems to be the most effective one. The paper presents the results of the strength examination of the influence of the different ways of layered polymerization processing on the mechanical properties of modern hybrid micro composite material with regards to the following quantities: compressive strength, strain to fracture, modulus of elasticity and work to fracture.

The Influence of Pore-Strucrure on the Campressive Strength of Hardened Cement Paste

1984 ◽  
Vol 42 ◽  
Author(s):  
Huang Yiun-Yuan ◽  
Ding Wei ◽  
Lu Ping
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Pore Structure ◽  
Cement Paste ◽  
Total Porosity ◽  
Hardened Cement ◽  
Hardened Cement Paste ◽  
New Information ◽  
The Relationship ◽  
Empirical Constants

AbstractThe pore-structure strongly influences the carpressive strength of hardened cement paste (hcp) and other porous materials, as well as other mechanical properties. The simplest but most currently used expression representing the relationship between the pore-structure and compressive strength is fram Balshin: σ = σ0 (l-P)A, in which only the total porosity P is involved as a single parameter and σ0 and A are empirical constants. The influence of pore size distribution and pore shapes etc. are not considered.The authors introduce second parameter w - the factor of relative specific surface area of the pores other than the total porosity P into consideration and a new expression is proposed:σc=K11-p/1+2p(K2(1-p))K3w+K4 all the constants K1 - K4 can be determined experimentally. By using of this expression the new information relating the influence of pore-structure on the caopressive strength of hcp can be predicted.

Evaluating the potential of different carbon sources to promote denitrification

2020 ◽  
Vol 158 (3) ◽  
pp. 194-205
Author(s):  
J. C. Dlamini ◽  
D. Chadwick ◽  
J. M. B. Hawkins ◽  
J. Martinez ◽  
D. Scholefield ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Carbon Sources ◽  
Organic Soil ◽  
Mitigation Strategies ◽  
Molar Ratio ◽  
Pig Slurry ◽  
Molar Ratios ◽  
Organic Soil Amendments ◽  
The Relationship ◽  
Denitrification Process

AbstractOrganic carbon (C) plays an essential role in the denitrification process as it supplies energy for N2O, N2 and CO2 producing reactions. The objectives of this study were to: (i) rank the reactivity of different C compounds found in manures based on their availability for denitrification and (ii) explore C-quality in different C sources based on their capacity to promote denitrification. Evaluation of different C-sources in promoting denitrification was conducted based on the molar ratio of CO2 production to NO3− reduction after incubation. Results of the first experiment (a 12-day investigation) showed that glucose and glucosamine were highly reactive C compounds with all applied NO3− being exhausted by day 3, and glucosamine had significantly high amount of NH4+-N present at end of the experiment. The glucose and glucosamine treatments resulted in significantly greater cumulative CO2 production, compared to the other treatments. In the second experiment (a 9-day investigation), all NO3− had been depleted by day 6 and 9 from acetic acid and glucose, respectively, and the greatest cumulative CO2 production was from acetic acid. The CO2 appearance to NO3− molar ratios revealed that glucose and glucosamine were compounds with highly available C in the first experiment. In the second experiment, the pig slurry and acetic acid were found to be C-sources that promoted potential denitrification. The application of slurry to soil results in the promotion of denitrification and this depends on the availability of the C compounds it contains. Understanding the relationship between C availability and denitrification potential is useful for developing denitrification mitigation strategies for organic soil amendments.

scholarly journals Metakaolinite Phosphate Cementitious Matrix: Inorganic Polymer Obtained by Acidic Activation

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 442 ◽  
Author(s):  
Antigoni Katsiki ◽  
Tobias Hertel ◽  
Tine Tysmans ◽  
Yiannis Pontikes ◽  
Hubert Rahier
Keyword(s):  
Compressive Strength ◽  
Optimum Composition ◽  
Molar Ratio ◽  
High Porosity ◽  
X Ray Diffraction ◽  
Promising Candidate ◽  
Cementitious Matrix ◽  
Molar Ratios ◽  
Optimal Behavior ◽  
Amorphous Network

This work aims to study an aluminosilicate phosphate cementitious matrix. The cementitious matrix was studied on paste samples. The synthesis of metakaolinite phosphate cement (MKPC) was investigated using calorimetric techniques. A systematic study was performed by emphasizing a broad range of Al/P molar ratios, covering the different behavior of the material to the extremes, as well as the optimum composition. X-ray diffraction and scanning electron microscopy revealed that the final structure was mainly an amorphous network, albeit with some non-reacted phases. The compressive strength was studied on mortars using a cement/sand ratio of 1:3. MKPC specimens with Al/P ratios close to 1/1 showed optimal behavior. MKPCs with Al/P ratios above 1/1 were characterized by high porosity and low strength, whereas MKPCs with Al/P < 1 contained an excess of phosphates. The influence of the Al/P molar ratio on compressive strength was also studied, reaching a maximum of 68 MPa for the optimum composition. Based on the results, MKPC may be a promising candidate for construction purposes.

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