scholarly journals Combined Effects of Curing Temperatures and Alkaline Concrete on Tensile Properties of GFRP Bars

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Wen-rui Yang ◽  
Xiong-jun He ◽  
Kai Zhang ◽  
Yang Yang ◽  
Li Dai
Keyword(s):  
Tensile Strength ◽  
Tensile Properties ◽  
Correlation Equation ◽  
Immersion Test ◽  
Test Methods ◽  
Curing Temperature ◽  
Mechanical Degradation ◽  
Combined Effects ◽  
Scanning Calorimetry ◽  
Gfrp Bars

A significant number of studies have been conducted on the tensile properties of GFRP bars embedded in concrete under different environments. However, most of these studies have been experimentally based on the environmental immersion test after standard-curing and the lack of influence on the tensile properties of GFRP bars embedded in concrete during the curing process of concrete. This paper presents the results of the microscopic structures through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and tensile properties of GFRP bars, which were employed to investigate the combined effects of curing temperatures and alkaline concrete on tensile properties of GFRP bars. The results showed that the higher curing temperature aggravated the influence of the alkaline concrete environment on GFRP bars but did not change the mechanisms of mechanical degradation of the GFRP bars. The influence of different curing temperatures on the tensile strength of GFRP bars was different between the bare bar and bars in concrete. Finally, the exponential correlation equation of two different test methods was established, and the attenuation ratio of the tensile strength of GFRP bars embedded in concrete under different curing temperatures was predicted by the bare test.

scholarly journals Combined Effects of Cellulose Nanofiber Nucleation and Maleated Polylactic Acid Compatibilization on the Crystallization Kinetic and Mechanical Properties of Polylactic Acid Nanocomposite

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3226
Author(s):  
Siti Shazra Shazleen ◽  
Lawrence Yee Foong Ng ◽  
Nor Azowa Ibrahim ◽  
Mohd Ali Hassan ◽  
Hidayah Ariffin
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Polylactic Acid ◽  
Crystallization Kinetics ◽  
Crystallization Kinetic ◽  
Crystallization Rate ◽  
Combined Effects ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Isothermal Crystallization Kinetics

This work investigated the combined effects of CNF nucleation (3 wt.%) and PLA-g-MA compatibilization at different loadings (1–4 wt.%) on the crystallization kinetics and mechanical properties of polylactic acid (PLA). A crystallization kinetics study was done through isothermal and non-isothermal crystallization kinetics using differential scanning calorimetry (DSC) analysis. It was shown that PLA-g-MA had some effect on nucleation as exhibited by the value of crystallization half time and crystallization rate of the PLA/PLA-g-MA, which were increased by 180% and 172%, respectively, as compared to neat PLA when isothermally melt crystallized at 100 °C. Nevertheless, the presence of PLA-g-MA in PLA/PLA-g-MA/CNF3 nanocomposites did not improve the crystallization rate compared to that of uncompatibilized PLA/CNF3. Tensile strength was reduced with the increased amount of PLA-g-MA. Contrarily, Young’s modulus values showed drastic increment compared to the neat PLA, showing that the addition of the PLA-g-MA contributed to the rigidity of the PLA nanocomposites. Overall, it can be concluded that PLA/CNF nanocomposite has good performance, whereby the addition of PLA-g-MA in PLA/CNF may not be necessary for improving both the crystallization kinetics and tensile strength. The addition of PLA-g-MA may be needed to produce rigid nanocomposites; nevertheless, in this case, the crystallization rate of the material needs to be compromised.

scholarly journals Investigation on tensile properties of epoxy/graphene nano-platelets/carboxylated nitrile butadiene rubber ternary nanocomposites using response surface methodology

2019 ◽  
Vol 9 ◽  
pp. 184798041985584 ◽  
Author(s):  
Mohammadhossein Saberian ◽  
Faramarz Ashenai Ghasemi ◽  
Ismail Ghasemi ◽  
Sajjad Daneshpayeh
Keyword(s):  
Tensile Strength ◽  
Response Surface Methodology ◽  
Tensile Properties ◽  
Response Surface ◽  
Tensile Modulus ◽  
Curing Temperature ◽  
Butadiene Rubber ◽  
Elongation At Break ◽  
Low Concentration ◽  
Nitrile Butadiene Rubber

In this study, the response surface methodology was used to investigate the tensile properties of epoxy/graphene nano-platelets/carboxylated nitrile butadiene rubber ternary nanocomposites. Box–Benhken method was used to design experiments for four factors consisting of graphene nano-platelets (at 0, 0.75, and 1.5 wt%), carboxylated nitrile butadiene rubber (0, 5, and 10 wt%), hardener contents (80, 90, and 100 phr), and also different post curing temperature (130, 140, and 150°C). After the samples were prepared, a tensile test was performed to obtain the tensile strength, tensile modulus, and elongation at break of nanocomposites. Moreover, field-emission scanning electron microscopy was used to observe the state of graphene nano-platelets dispersion. The results obtained from the tensile tests showed that increasing the graphene nano-platelets, carboxylated nitrile butadiene rubber, and hardener contents and high post curing temperature reduced the tensile strength. The optimum value of tensile modulus was achieved at low concentration of carboxylated nitrile butadiene rubber and high contents of graphene nano-platelets, whereas maximum elongation at break occurred at high content of carboxylated nitrile butadiene rubber and low concentration of graphene nano-platelets and hardener. In addition, a second-order polynomial model was used to correlate the tensile properties of ternary nanocomposites to the desired factors. Finally, contour plots were used to determine optimum values of the desired factors. It was seen that the presence of 10 wt% of carboxylated nitrile butadiene rubber in the epoxy matrix increased the elongation at break by the considerable amount of ∼49%.

scholarly journals Tensile Strength and Degradation of GFRP Bars under Combined Effects of Mechanical Load and Alkaline Solution

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3533 ◽  
Author(s):  
Qingping Jin ◽  
Peixia Chen ◽  
Yonghong Gao ◽  
Aihua Du ◽  
Dongxu Liu ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Alkaline Solution ◽  
Mechanical Load ◽  
Three Dimensional ◽  
Strength Degradation ◽  
Combined Effects ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Stress Levels

Mechanical properties of glass fiber reinforced polymer (GFRP) composites degrade under the combined effects of mechanical load and alkaline solution, affecting the service ability and safety of GFRP reinforced structures. In this study, GFRP bars were loaded with cyclic tension at different stress levels and immersed in alkaline solution for days to investigate the tensile properties and degradation law of GFRP bars. The degradation mechanisms were studied at micro-, meso- and macro-scales with scanning electron microscopy (SEM) and three-dimensional X-ray microscopy, respectively. The results show that tensile strength and degradation rate of GFRP bars are mainly dependent on the different stress levels and alkaline solution. When stress level is higher, the tensile strength degrades more quickly, especially in the early stages of soaking. With the loading and immersion time, the elastic modulus and Poisson’s ratio increase at first and then decrease. The ultimate tensile strain is relatively stable, whereas the ultimate elongation is significantly reduced. A strength-degradation model was proposed and fit well with experimental data, demonstrating that the model can be applied to predict tensile strength degradation under combined effects of the load and alkaline solution.

Effects of Cu on the Microstructures and Tensile Properties of Thixoformed Al-Si Alloys

2014 ◽  
Vol 217-218 ◽  
pp. 91-98
Author(s):  
Mohd Shukor Salleh ◽  
Mohd Zaidi Omar ◽  
Junaidi Syarif ◽  
K.S. Alhawari ◽  
M.N. Mohammed
Keyword(s):  
Tensile Strength ◽  
Tensile Properties ◽  
Copper Content ◽  
Liquid Fraction ◽  
Tensile Tests ◽  
Scanning Calorimetry ◽  
Cu Content ◽  
Semi Solid ◽  
Cooling Slope Casting ◽  
Solid Liquid

In this study, the effects of copper content on the microstructures and tensile properties of thixoformed Al-5Si-xCu-0.5Fe (x =1.0, 2.0 and 3.0 wt. %) were investigated. For this study, three different alloys having various amounts of copper were prepared using cooling slope casting before thixoforming. The semi-solid liquid range for the alloys were estimated using the diffrential scanning calorimetry (DSC) analysis. The samples were thixoformed at 40% liquid fraction. Some of these samples were treated with a T6 aging process. The thixoformed and thixoformed T6 samples were then characterized by optical microscopy, scanning electron microscope (SEM) and energy dispersive X-ray (EDX) as well as tensile tests. The different phases formed in the thixoformed and thixoformed T6 samples were throughly investigated.The results indicate that as copper content increases, the tensile strength also increases, which might due to precipitation hardening. The thixoformed T6 alloys attained an ultimate tensile strength (UTS) as high as 303 MPa when Cu content is 3 wt%.

Effect of curing cycles using wet prepreg processing on mechanical properties

2018 ◽  
Vol 32 (19) ◽  
pp. 1840076
Author(s):  
Chen Zixuan ◽  
Yu Tianyu ◽  
Kyung-Seok Jung ◽  
Chang-Wook Park ◽  
Soo-Jeong Park ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Manufacturing Process ◽  
Curing Temperature ◽  
Forming Process ◽  
Scanning Calorimetry ◽  
Reinforced Plastic ◽  
The Matrix ◽  
Matrix Reinforcement ◽  
Opposite Tendency

For the fabrication of polymer-based composite materials, the interpretation of an appropriate fabrication process is essential to improve the productivity and manufacturing process. In this study, the wet prepreg forming process was used to fabricate carbon fiber reinforced plastic (CFRP) and different curing cycles were demonstrated for an optimal process. To determine the range of curing temperature, a pretreatment on differential scanning calorimetry (DSC) analysis was performed. After that, tensile and ILSS tests were adopted to investigate the mechanical properties and thermal analysis on a matrix carried out by the DSC equipment. Different volumes of the matrix residue on fractured fiber, which represent the matrix-reinforcement adhesion strength, were observed by a scanning electron microscope (SEM). Also, a void aggregation was found in high curing temperature situation due to excessive exotherm. Both the tensile strength and ILSS held a certain trend with the changing curing cycles. The highest tensile strength (469 MPa) and glass transition temperature (Tg) at 91.58[Formula: see text]C occurred at 80[Formula: see text]C and 12 h curing temperature and time, respectively. The result of ILSS had an almost opposite tendency of the tensile strength. A correlation between Tg and mechanical properties was observed and it can be extensively applied to optimize the manufacturing process.

The Effects on Tensile Properties of Different Winding Way on GFRP Bar

2013 ◽  
Vol 438-439 ◽  
pp. 357-360
Author(s):  
Yu Yang Pang ◽  
Pu Zhang ◽  
Dan Ying Gao ◽  
Fei Mo
Keyword(s):  
Tensile Strength ◽  
Tensile Properties ◽  
Modulus Of Elasticity ◽  
Tensile Tests ◽  
Test Results ◽  
Shear Properties ◽  
Gfrp Bars ◽  
Ultimate Elongation ◽  
Gfrp Bar ◽  
Gfrp Reinforcement

The influence of different surface forms on GFRP reinforcement mainly manifest in bonding between reinforcement materials and concrete, especially when the GFRP bars are used in slope, the form of the surface of GFRP bar will affect reinforced materials torsion and shear properties directly. This article made some tensile tests on several different surface forms of GFRP reinforcement, and learned that the form of the surface wound of GFRP bar make the influence on tensile strength, ultimate elongation and modulus of elasticity. Test results show that the surface of the winding way will affect on the tensile strength, ultimate elongation and modulus of elasticity of GFRP bar.

scholarly journals Experimental Evaluation of Tensile Performance of Aluminate Cement Composite Reinforced with Weft Knitted Fabrics as a Function of Curing Temperature

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4385
Author(s):  
Bentolhoda Adosi ◽  
Seyed Abbas Mirjalili ◽  
Mostafa Adresi ◽  
Jean-Marc Tulliani ◽  
Paola Antonaci
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Tensile Properties ◽  
Retaining Wall ◽  
Cement Composite ◽  
Curing Temperature ◽  
Cementitious Composites ◽  
Absorbed Energy ◽  
Curing Conditions ◽  
Aluminate Cement

Cement composites (CC) are among the composites most widely used in the construction industry, such as a durable waterproof and fire-resistant concrete layer, slope protection, and application in retaining wall structures. The use of 3D fabric embedded in the cement media can improve the mechanical properties of the composites. The use of calcium aluminate cement (CAC) can accelerate the production process of the CC and further contribute to improving the mechanical properties of the cement media. The purpose of this study is to promote the use of these cementitious composites by deepening the knowledge of their tensile properties and investigating the factors that may affect them. Therefore, 270 specimens (three types of stitch structure, two directions of the fabric, three water temperature values, five curing ages, with three repetitions) were made, and the tensile properties, absorbed energy, and the inversion effects were evaluated. The results showed that the curing conditions of the reinforced cementitious composite in water with temperature values of 7, 23, and 50 °C affect the tensile behavior. The tensile strength of the CCs cured in water with a temperature of 23 °C had the highest tensile strength, while 7 and 50 °C produced a lower tensile strength. The inversion effect has been observed in CC at 23 °C between 7 and 28 days, while this effect has not occurred in other curing temperature values. By examining three commercial types of stitches in fabrics and the performance of the reinforced cementitious composites in the warp direction, it was found that the structure of the “Tuck Stitch” has higher tensile strength and absorbed energy compared to “Knit stitch” and “Miss Stitch”. The tensile strength and fracture energy of the CC reinforced with “Tuck Stitch” fabric in the warp direction, by curing in 23 °C water for 7 days, were found to be 2.81 MPa and 1.65 × 103 KJ/m3, respectively. These results may be helpful in selecting the design and curing parameters for the purposes of maximizing the tensile properties of textile CAC composites.

Variasi Penambahan Sika Cim Dan Fiber Kawat Pada Beton Mutu Fc’ 30 Mpa

2018 ◽  
Vol 9 (2) ◽  
pp. 67-73
Author(s):  
M Zainul Arifin
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Curing Temperature ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Normal Concrete ◽  
Astm Method ◽  
Additive Type ◽  
Composition Variation ◽  
Compressive Strength Of Concrete

This research was conducted to determine the value of the highest compressive strength from the ratio of normal concrete to normal concrete plus additive types of Sika Cim with a composition variation of 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1 , 50% and 1.75% of the weight of cement besides that in this study also aims to find the highest tensile strength from the ratio of normal concrete to normal concrete in the mixture of sika cim composition at the highest compressive strength above and after that added fiber wire with a size diameter of 1 mm in length 100 mm with a ratio of 1% of material weight. The concrete mix plan was calculated using the ASTM method, the matrial composition of the normal concrete mixture as follows, 314 kg / m3 cement, 789 kg / m3 sand, 1125 kg / m3 gravel and 189 liters / m3 of water at 10 cm slump, then normal concrete added variations of the composition of sika cim 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.5%, 1.75% by weight of cement and fiber, the tests carried out were compressive strength of concrete and tensile strength of concrete, normal maintenance is soaked in fresh water for 28 days at 30oC. From the test results it was found that the normal concrete compressive strength at the age of 28 days was fc1 30 Mpa, the variation in the addition of the sika cim additive type mineral was achieved in composition 0.75% of the cement weight of fc1 40.2 Mpa 30C. Besides that the tensile strength test results were 28 days old with the addition of 1% fiber wire mineral to the weight of the material at a curing temperature of 30oC of 7.5%.

A method for measuring the in-plane compressive strength and the compression behavior of coating layers

TAPPI Journal ◽  
2011 ◽  
Vol 10 (7) ◽  
pp. 29-34
Author(s):  
TEEMU PUHAKKA ◽  
ISKO KAJANTO ◽  
NINA PYKÄLÄINEN
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Calcium Carbonate ◽  
Coating Layer ◽  
Test Methods ◽  
Coating Films ◽  
Precipitated Calcium Carbonate ◽  
Coating Color ◽  
Mineral Coatings ◽  
Styrene Butadiene

Cracking at the fold is a quality defect sometimes observed in coated paper and board. Although tensile and compressive stresses occur during folding, test methods to measure the compressive strength of a coating have not been available. Our objective was to develop a method to measure the compressive strength of a coating layer and to investigate how different mineral coatings behave under compression. We used the short-span compressive strength test (SCT) to measure the in-plane compressive strength of a free coating layer. Unsupported free coating films were prepared for the measurements. Results indicate that the SCT method was suitable for measuring the in-plane compressive strength of a coating layer. Coating color formulations containing different kaolin and calcium carbonate minerals were used to study the effect of pigment particles’ shape on the compressive and tensile strengths of coatings. Latices having two different glass transition temperatures were used. Results showed that pigment particle shape influenced the strength of a coating layer. Platy clay gave better strength than spherical or needle-shaped carbonate pigments. Compressive and tensile strength decreased as a function of the amount of calcium carbonate in the coating color, particularly with precipitated calcium carbonate. We also assessed the influence of styrene-butadiene binder on the compressive strength of the coating layer, which increased with the binder level. The compressive strength of the coating layer was about three times the tensile strength.

SINTESIS DAN MODIFIKASI STRUKTUR DAN PORI MEMBRAN KITOSAN TERCROSSLINK UNTUK STERILISASI MEDIA PERTUMBUHAN BAKTERI

2019 ◽  
Vol 3 (2) ◽  
pp. 27
Author(s):  
Emma Savitri ◽  
Natalia Suseno ◽  
Tokok Adiarto
Keyword(s):  
Tensile Strength ◽  
Chitosan Solution ◽  
Curing Temperature ◽  
Growth Media ◽  
Optimum Conditions ◽  
Separation Processes ◽  
Crosslinking Process ◽  
Chitosan Membrane ◽  
Chitosan Membranes ◽  
Crosslinked Chitosan

Many mass-transfer applications have used chitosan membrane in separation processes. This research applied crosslinked chitosan membrane to sterillize bacterial growth media. Chitosan membranes having 79 % DD were produced by casting and drying chitosan solution. The images of the membrane were characterized by SEM and other characterizations such as permeability, permselectivity and tensile strength were investigated. The flux increased with longer submersion period but the rejection decreased. Otherwise, the flux decreased and rejection increased in line with an increase in curing temperature. Tensile strength increased with the increase of submersion period and curing temperature. The optimum conditions of crosslinking process are 2 hours of submersion periods and curing temperature at 90 oC.  It gives flux 5.8930 L/jam.m2, rejection 97.47 % and tensile strength 49640 kN/m2

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