scholarly journals Influence of nanoclays on water uptake and flexural strength of glass–polyester composites

2020 ◽  
Vol 18 ◽  
pp. 228080002093018
Author(s):  
Ali Nemati Giv ◽  
Sina Rastegar ◽  
Mutlu Özcan
Keyword(s):  
Flexural Strength ◽  
Water Absorption ◽  
High Strength ◽  
Time Duration ◽  
Sem Images ◽  
Water Absorption Test ◽  
Polyester Composites ◽  
Chopped Strand Mat ◽  
Nanoclay Content ◽  
Composite Samples

Fiber-reinforced polyester composites have received significant attention in a variety of applications due to their considerable potential due to such characteristics as high strength, stiffness, and modulus. However, one of the most important concerns about polymeric composites is their sensitivity to moisture attack. This work has been conducted to investigate the effects of nanoclay addition on reinforcing glass/polyester composites against water absorption and the resultant deterioration of flexural strength. Therefore, chopped strand mat and woven fiberglass polyester specimens were fabricated by using the hand lay-up technique with varying weight percentages of Cloisite 20A nanoclays (0, 1.5, and 3 wt%) and immersion in water for a time duration of 21 days. The specimens were weighed for the water absorption test. The results showed a remarkable drop in water absorption of the composite samples with the increase of nanoclay content. Moreover, although all the pure and nanocomposite specimens underwent degradation in flexural strength due to the water absorption, the strength was found to significantly increase with increasing the percentage of nanoclay at all immersion periods. The experimental results were confirmed by scanning electron microscopy (SEM). SEM images indicated that the presence of nanoclay protected the fiber/matrix interfaces.

Studies on Tensile and Water Absorption Properties on Kenaf (Hibiscus Cannabinus) Fibre Mat/Polyester Composite Using Chemical Treatment

2013 ◽  
Vol 421 ◽  
pp. 290-295
Author(s):  
Mohammad Taib Mohamad Nurul Azman ◽  
Abu Kassim Masitah ◽  
Ariff Jamaludin Mohd ◽  
Ismail Tayibbah
Keyword(s):  
Water Absorption ◽  
Treatment Duration ◽  
Hibiscus Cannabinus ◽  
Absorption Test ◽  
Duration Of Treatment ◽  
Absorption Properties ◽  
Kenaf Fibre ◽  
Polyester Composite ◽  
Water Absorption Test ◽  
Polyester Composites

This research investigated the tensile and water absorption properties of kenaf fibre mat/polyester composites. Treatment using acetylation method has been introduced to improve the properties of product manufactured. The effects of acetylation treatment with three variations of time that were 1, 4 and 24 hours on the kenaf fibre mats were investigated. The MOE of the tensile of treated fibre mat/polyester composite for 1 hour was the highest with value 4589.61 MPa. The tensile strength of treated fibre mat/polyester composite for 4 hours was the highest with value 0.6213 MPa. For water absorption test, the results showed that fibre mat/polyester composite with treatment duration for 1 hour had the lowest water absorption that was 1.23% compared with treatment duration for 4 hours and 24 hours. For overall it can be concluded that the treatment duration of 1 hour was recommended for acetylation method when compared with 4 hours and 24 hours duration treatments. Using acetylation treatment on the kenaf fibre mat/polyester composites was showed improvement on composite and was recommended in short duration of treatment.

scholarly journals Thermal Action on Normal and High Strength Cement Mortars

2020 ◽  
Vol 10 (18) ◽  
pp. 6455
Author(s):  
Marianela Ripani ◽  
Hernán Xargay ◽  
Ignacio Iriarte ◽  
Kevin Bernardo ◽  
Antonio Caggiano ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Peak Load ◽  
Physical And Mechanical Properties ◽  
Thermal Action ◽  
High Strength ◽  
Strength Loss ◽  
Brittle Behavior ◽  
Cement Mortars ◽  
Water Absorption Test

High temperature effect on cement-based composites, such as concrete or mortars, represents one of the most important damaging process that may drastically affect the mechanical and durability characteristics of structures. In this paper, the results of an experimental campaign on cement mortars submitted to high temperatures are reported and discussed. Particularly, two mixtures (i.e., Normal (MNS) and High Strength Mortar (MHS)) having different water-to-binder ratios were designed and evaluated in order to investigate the incidence of both the mortar composition and the effects of thermal treatments on their physical and mechanical properties. Mortar specimens were thermally treated in an electrical furnace, being submitted to the action of temperatures ranging from 100 to 600 °C. After that and for each mortar quality and considered temperature, including the room temperature case of 20 °C, water absorption was measured by following a capillary water absorption test. Furthermore, uniaxial compression, splitting tensile and three-points bending tests were performed under residual conditions. A comparative analysis of the progressive damage caused by temperature on physical and mechanical properties of the considered mortars types is presented. On one hand, increasing temperatures produced increasing water absorption coefficients, evidencing the effect of thermal damages which may cause an increase in the mortars accessible porosity. However, under these circumstances, the internal porosity structure of lower w/b ratio mixtures results much more thermally-damaged than those of MNS. On the other hand, strengths suffered a progressive degradation due to temperature rises. While at low to medium temperatures, strength loss resulted similar for both mortar types, at higher temperature, MNS presented a relatively greater strength loss than that of MHS. The action of temperature also caused in all cases a decrease of Young’s Modulus and an increase in the strain corresponding to peak load. However, MHS showed a much more brittle behavior in comparison with that of MNS, for all temperature cases. Finally, the obtained results demonstrated that mortar quality cannot be neglected when the action of temperature is considered, being the final material performance dependent on the physical properties which, in turn, mainly depend on the mixture proportioning.

Preparation and Characterization of β-SiAlON Ceramics from High Aluminium Fly Ash via Carbothermal Reduction-Nitridation

2007 ◽  
Vol 561-565 ◽  
pp. 587-590 ◽  
Author(s):  
Jin Hong Li ◽  
Hong Wen Ma ◽  
Ying Cao
Keyword(s):  
Fly Ash ◽  
Flexural Strength ◽  
Physicochemical Properties ◽  
Water Absorption ◽  
Bulk Density ◽  
Carbothermal Reduction ◽  
Sintering Temperature ◽  
Sem Images ◽  
High Aluminium

In this work, β-sialon ceramics were prepared from high-aluminium fly ash via carbothermal reduction-nitridation (CRN) and the physicochemical properties of the materials such as bulk density, apparent porosity, water absorption and flexural strength were also discussed. The results showed that the percentage of β-sialon phase in the product decreases as the temperature increases from 1400°C and the weight of the sintered specimen experienced an increase during 1350°C~1450°C due to the nitridation reactions, and followed by a gradual decrease till 1550°C for the decomposition of β-sialon. It is indicated that the optimum sintering temperature to obtain the highest yield of β-sialon ~93% lies in 1400°C~1450°C. The SEM images revealed that the prepared β-sialon sintered at 1400°C were mainly in shape of elongated prisms, typically ~5μm in length and 0.5~1μm in width. As the temperature increased to 1500°C and above, β-sialon decomposed and the new phases of SiC and AlN were formed at 1550°C as confirmed by XRD.

The Effect of Ultraviolet Exposure on Physical Properties of Electrospun Nanofiber Membrane Based on Polyvinyl Alcohol and Aloe vera

2020 ◽  
Vol 860 ◽  
pp. 244-250
Author(s):  
Dyah Hikmawati ◽  
Noveni Putri Maharani ◽  
Alfian Pramudita Putra ◽  
Siswanto
Keyword(s):  
Polyvinyl Alcohol ◽  
Physical Properties ◽  
Water Absorption ◽  
Aloe Vera ◽  
Uv Exposure ◽  
Absorption Test ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
Water Absorption Test ◽  
Test Result

Ultraviolet (UV) irradiation in biomaterial synthesis is commonly used to do sterilization and increase physical characteristics. This study had a goal to evaluate the characteristics of polyvinyl alcohol-Aloe vera (PVA-AV) nanofibers from the electrospinning process that was exposed by UV with the power of 8, 10, 15, and 20 W for 6 h. The physical properties of the fiber were characterized by using Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), Differential Scanning Calorimetry (DSC) test, and water absorption test. The SEM images showed that the nanofibers were formed with s homogeneous structure and no beads. The diameter and the thickness of the nanofibers increased with the increase of the power of UV exposure to the sample. The biggest diameter was 319.60 ± 56.17 nm at UV exposure power of 20 W. The FTIR test result indicated that there was no new chemical bond after the PVA-AV was exposed by UV. DSC test result showed that the increase of power could increase the melting temperature (Tm) with the highest value of 189.51°C at UV exposure power of 20 W. The water absorption test showed that the highest water absorption was 739.6 % at UV exposure power of 20 W.

COMPUTER-AIDED PREDICTION OF PHYSICAL AND MECHANICAL PROPERTIES OF HIGH STRENGTH CEMENTITIOUS COMPOSITE CONTAINING Cr2O3 NANOPARTICLES

NANO ◽  
2010 ◽  
Vol 05 (05) ◽  
pp. 301-318 ◽  
Author(s):  
ALI NAZARI ◽  
SHADI RIAHI
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Flexural Strength ◽  
Genetic Programming ◽  
Water Absorption ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Programming Models ◽  
Input Parameters ◽  
Percentage Of Water Absorption

In the present paper, two models based on artificial neural networks (ANN) and genetic programming (GEP) for predicting flexural strength and percentage of water absorption of concretes containing Cr2O3 nanoparticles have been developed at different ages of curing. For purpose of building these models, training and testing using experimental results for 144 specimens produced with 16 different mixture proportions were conducted. The data used in the multilayer feed forward neural networks models and input variables of genetic programming models are arranged in a format of eight input parameters that cover the cement content (C), nanoparticle content (N), aggregate type (AG), water content (W), the amount of superplasticizer (S), the type of curing medium (CM), Age of curing (AC) and number of testing try (NT). According to these input parameters, in the neural networks and genetic programming models the flexural strength and percentage of water absorption values of concretes containing Cr2O3 nanoparticles were predicted. The training and testing results in the neural network and genetic programming models have shown that every two models have strong potential for predicting the flexural strength and percentage of water absorption values of concretes containing Cr2O3 nanoparticles. Although neural network have predicted better results, genetic programming is able to predict reasonable values with a simpler method rather than neural network.

Effect of Polypropylene Macro-Fiber on Properties of High-Strength Concrete at Elevated Temperatures

2014 ◽  
Vol 629-630 ◽  
pp. 284-290 ◽  
Author(s):  
Xu Jing Niu ◽  
Qing Xin Zhao ◽  
Ying Nie
Keyword(s):  
Flexural Strength ◽  
Mass Loss ◽  
Water Absorption ◽  
High Strength Concrete ◽  
Loss Rate ◽  
Elevated Temperatures ◽  
Mass Loss Rate ◽  
High Strength ◽  
Hybrid Fibers ◽  
Strength Concrete

After being subjected to different elevated temperatures, ranging between 200 °C and 800 °C, the flexural strength, matrix mass loss rate and water absorption of polypropylene (PP) macro-fiber reinforced high strength concrete (HSC) were investigated. Moreover, the internal damage of concrete was analyzed by the ultrasonic non-destructive testing technology. The results indicate that PP macro-fiber in HSC has an adverse effect on flexural strength, while the synergistic effect of hybrid fibers (PP micro-fiber plus PP macro-fiber) can minimize this effect. Compared with PP micro-fiber, PP macro-fiber is more effective in increasing the matrix mass loss rate and water absorption of HSC. However, if the dosage of PP macro-fiber is too high, the pressure relief channels formed by fibers melt will be too coarse, and the total porosity of HSC will be increased significantly. Finally, a mathematical model relating the damage degree to temperature was established based on the non-linear fitting of the experimental data.

Tensile, Flexural and Water Absorption Properties of Bamboo Fiber/Unsaturated Polyester Composites: Effect of Calcium Carbonate Content

2020 ◽  
Vol 867 ◽  
pp. 68-74
Author(s):  
Sugiman Sugiman ◽  
Atin Martino ◽  
Paryanto Dwi Setyawan ◽  
Buan Anshari
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Water Absorption ◽  
Unsaturated Polyester ◽  
Bamboo Fiber ◽  
Flexural Properties ◽  
Carbonate Content ◽  
Absorption Properties ◽  
Polyester Composites

The paper presents the effect of CaCO3 content on the tensile, flexural and water absorption properties of bamboo fiber/polystyrene-modified unsaturated polyester composites. Two volume fractions of bamboo fibers had been used with the CaCO3 content varied from 2.5 to 10 (wt%). The tensile and flexural properties were used to characterize the composites. In addition, the water absorption and its effect of the flexural properties had also been conducted. The results showed that at the bamboo content of 30%, adding CaCO3 up to 10wt% tended to decrease the tensile strength and elastic modulus of bamboo fiber/modified unsaturated polyester composites up to 27% and 4%, respectively; however, at the bamboo content of 20%, its effect was not significant for both the tensile strength and the elastic modulus. Adding CaCO3 seemed not to have a significant effect for both the flexural strength and modulus. Having exposed in distilled water, CaCO3 did not significantly affect the water uptakes and the flexural properties of bamboo fiber/modified unsaturated polyester composites; however, the flexural strength and modulus significantly decreased in the ranges of 24 - 45% and 36 - 43%, respectively, compared to those in dry condition.

Influence of Different Pore-Forming Mechanism on Superfinish Grinding Tools

2011 ◽  
Vol 418-420 ◽  
pp. 2024-2031
Author(s):  
Zhi Gang Zhang ◽  
Yu Mei Zhu ◽  
Zhi Hong Li
Keyword(s):  
Flexural Strength ◽  
Mechanical Strength ◽  
Water Absorption ◽  
High Porosity ◽  
Performance Tests ◽  
Working Mechanism ◽  
Sem Images ◽  
High Mechanical Strength ◽  
Forming Mechanism ◽  
Grinding Tool

Eight kinds of materials with diverse pore-forming mechanism were added into the ceramic ingredient of superfinish grinding tool with the same amount, and the specimens were prepared and sintered in the same condition. Their pore-forming abilities in the sintered bodies were compared through several performance tests. By measuring the porosity, bulk density, water absorption and flexural strength of these sintered bodies, and observing the SEM images, pore-forming agents with the best working mechanism was identified. It is proved that those pore-forming agents which have pore structures in themselves process the best pore-forming ability, and they can maintain relatively high porosity and high mechanical strength, which is good for the superfinish grinding tools.

scholarly journals STUDY OF SOME PROPERTIES FOR COLD-CURING ACRYLIC RESIN REIENFORCED WITH NANO YTTRIUM OXIDE

2018 ◽  
Vol 18 (1) ◽  
pp. 137-145
Author(s):  
Mohammed R Gharkan ◽  
Bassam I Khalil ◽  
Ahmed H Ali ◽  
Sally A H Kadhum ◽  
Ahmad H Aliwi
Keyword(s):  
Thermal Conductivity ◽  
Water Absorption ◽  
Water Adsorption ◽  
High Strength ◽  
Acrylic Resin ◽  
Weight Fraction ◽  
Mechanical Tests ◽  
Maximum Hardness ◽  
Conductivity Water ◽  
Composite Samples

Through the last two to three dictate, composite materials had being applied enormously inmany industry fields. This is as fact that this type of materials possess; high strength toweight ratio, high stiffness, and limit thermal conductivity. In this work Nano-Yttrium oxidewith (0%, 1%, 2%, 3% and 4%) weight fraction had been added, as reinforcement phase, toacrylic resin (cold curing). Various physical and mechanical tests had done for determiningthe development in the properties of the prepared composite samples like: hardness, tensilestrength, thermal conductivity, water absorption and density. The results show: decreasingtensile strength with increasing Nano-Y2O3 weight fraction, maximum decline in tensilestrength was at (4) % Y2O3, about (16.2) % of Acrylic strength; increasing in hardness withincreasing Nano-Y2O3 weight fraction, maximum hardness was at (4) % Y2O3, about (107)% of Acrylic hardness, no obviously density change with increasing Nano-Y2O3 weightfraction, decreasing water adsorption with increasing Nano-Y2O3 weight fraction, maximumdecreasing in water absorption percentage was at (4) % of Y2O3, about (93) % of Acrylicwater absorption, decreasing thermal conductivity with increasing weight fractions of Nano-Y2O3, maximum decline in thermal conductivity was at (4)% of Y2O3 , about (90)% ofAcrylic thermal conductivity

scholarly journals Investigation on the Properties of Mortar Containing Palm Oil Fuel Ash and Seashell Powder as Partial Cement Replacement

CONSTRUCTION ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 50-61
Author(s):  
K. Hasan ◽  
F.M. Yahaya ◽  
A. Karim ◽  
Rokiah Othman
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Water Absorption ◽  
Palm Oil ◽  
High Strength ◽  
Sustainable Construction ◽  
Partial Replacement ◽  
Palm Oil Fuel Ash ◽  
Fuel Ash ◽  
Oil Fuel

The concept of utilizing various types of wastes, such as agricultural dumps and marine by-products, as a partial replacement of cement has gained a great interest to develop eco-friendly and economical mortars for sustainable construction. This study aims to evaluate the feasibility of using palm oil fuel ash (POFA), an agro-industrial waste by-product from palm oil mills and seashell powder (SSP) derived from seashells, a marine waste material partial replacement of cement in mortars. The water to binder (w/b) ratio of 0.49 and the sand to binder (s/b) ratio of 2.54 with 0% to 30% of ordinary portland cement (OPC) by weight was replaced with POFA and SSP, and the resulting mortar samples were tested for mechanical properties and durability in this study. The compressive strength, flexural strength, water absorption, and flow table tests were performed in this study for different percentages of POFA and SSP after 7, 28, and 130 days. The results showed that the 30% POFA incorporated mortars achieved the highest compressive strength (35.12N/mm2), flexural strength (4.06N/mm2), high density with less water absorption (4.79%) after 130 days of curing and the high strength mortar with less water flow (22.2cm) during casting. Also, it found that the 25% POFA and 5% SSP incorporated mortars attained acceptable results as supplementary cementing material. This study suggests that the POFA and SSP incorporated mortars could be used in concrete for sustainable development of construction through the efficient valorization of waste materials.

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