Enhancement of the Compressive Strength of Kevlar-29/Epoxy Resin Unidirectional Composites

2007 ◽  
Vol 20 (3) ◽  
pp. 357-364 ◽  
Author(s):  
James D'Aloia ◽  
James A. Newell ◽  
Christopher Del Vecchio ◽  
Christopher Hill ◽  
David Santino ◽  
...  
2019 ◽  
Vol 32 (3) ◽  
pp. 306-315 ◽  
Author(s):  
Liang Xu ◽  
Yi He ◽  
Shaohua Ma ◽  
Li Hui

T800/high-temperature epoxy resin composites with different hole shapes were subjected to hygrothermal ageing and thermal-oxidative ageing, and the effects of these different ageing methods on the open-hole properties of the composites were investigated, including analyses of the mass changes, surface topography changes (before and after ageing), fracture morphologies, open-hole compressive performance, dynamic mechanical properties and infrared spectrum. The results showed that only physical ageing occurred under hygrothermal ageing (70°C and 85% relative humidity), and the equilibrium moisture absorption rate was only approximately 0.72%. In contrast, under thermal-oxidative ageing at 190°C, both physical ageing and chemical ageing occurred. After ageing, the open-hole compressive strength of the composite laminates with different hole shapes decreased significantly, but the open-hole compressive strength after thermal-oxidative ageing was greater than that after hygrothermal ageing. Among the aged and unaged laminates, the laminates with round holes exhibited the largest open-hole compressive strength, followed by those with the elliptical holes, square holes and diamond holes. The failure modes of the laminates were all through-hole failures. The unaged samples had a glass transition temperature ( T g) of 226°C, whereas the T g of the samples after hygrothermal ageing was 208°C, which is 18°C less than that of the unaged samples, and the T g of the samples after thermal-oxidative ageing was 253°C, which is 27°C greater than that of the unaged samples.


2017 ◽  
Vol 37 (4) ◽  
pp. 238-246
Author(s):  
Uri Breiman ◽  
Jacob Aboudi ◽  
Rami Haj-Ali

The compressive strength of unidirectional composites is strongly influenced by the elastic and strength properties of the fiber and matrix phases, as well as by the local geometrical properties, such as fiber volume fraction, misalignment, and waviness. In the present investigation, two microbuckling criteria are proposed and examined against a large volume of measured data of unidirectional composites taken from the literature. The first criterion is based on the compressive strength formulation using the buckling of Timoshenko’s beam. It contains a single parameter that can be determined according to the best fit to experimental data for various types of polymeric matrix composites. The second criterion is based on buckling-wave propagation analogy using the solution of an eigenvalue problem. Both criteria provide closed-form expressions for the compressive strength of unidirectional composites. We propose modifications of the two criteria by a fitting approach, for a wide range of fiber volume fractions, applied to four classes of unidirectional composite systems. Furthermore, a normalized form of the two models is presented after calibration in order to compare their prediction against experimental data for each of the material systems. The new modified criteria are shown to give a good match to a wide range of unidirectional composite systems. They can be employed as practical compression failure criteria in the analysis and design of laminated structures.


2019 ◽  
Vol 887 ◽  
pp. 40-47
Author(s):  
Tomáš Žlebek ◽  
Jakub Hodul ◽  
Rostislav Drochytka

The work deals with the use of waste glass to the polymer anchor material based on epoxy resin, primarily for anchoring to a high strength concrete (HSC). The main aim was to use the largest possible amount of the waste packaging glass by reducing the amount of epoxy resin, which is an expensive material and its production has a negative impact on the environment. Within the experimental verification, the influence of waste packaging glass fraction 0–0.63 mm on the final properties of the polymer anchoring material was observed. To determine the optimal formulation compressive strength, flexural strength, chemical resistance, shrinkage and pull-out test were performed. Based on the evaluation of the results the optimal percentage of filling was determined, when the polymer anchor material showed high strengths, minimal shrinkage, good chemical resistance, optimal consistency for anchoring into the HSC and high anchor bolt pull-out strength.


2011 ◽  
Vol 391-392 ◽  
pp. 807-811
Author(s):  
Fang Liu ◽  
Zhi Bin Zhang ◽  
Ling Ling Xu ◽  
Ming Shu Tang

The epoxy resin based repairing material(REM) is suitable for repairing cracks and holes in concrete or broken concrete due to its high bond strength and high durability. The compressive strength and flexile strength are 76.4MPa and >12.5MPa at 28d, and the retest strength still remain 73.4MPa and >12.5MPa respectively. The fracture location of cement mortar specimen bonded by RME is at cement mortar, that is, the bond strength between REM and cement mortar is more than mortar itself. The compressive strength of RME keeps 93.3% under ultraviolet light radiation (Peak Value 308nm, 49.5 W/m2) for 1700h.


2015 ◽  
Vol 1088 ◽  
pp. 411-414 ◽  
Author(s):  
Francisco Augusto Zago Marques ◽  
Carlos Eduardo G. da Silva ◽  
André Luis Christoforo ◽  
Francisco Antonio Rocco Lahr ◽  
Túlio Hallak Panzera ◽  
...  

This research evaluated, with the of the analyses of variance (ANOVA), a composite material based on epoxy matrix phase reinforced with Portland cement (CP-II) particles (0%wt [100%wt of resin], 20%wt, 40%wt, 60%wt). The response-variable investigated were modulus of elasticity (E) and compressive strength (S), bulk density (ρB), apparent density (ρA) and porosity (P). The highest values of the modulus of elasticity were provided from the composites manufactured with 40wt% of cement addition. The inclusion of 60% of cement implies in a reduction in the mechanical properties when compared with the results of the composite manufactured with 40% of cement. For the physical properties, the gradually inclusion of cement provides increasing in the density of the composites, and reduce the porosity of the materials manufactured.


2017 ◽  
Vol 152 ◽  
pp. 990-998 ◽  
Author(s):  
Nan Ji Jin ◽  
Inbae Seung ◽  
Yoon Sang Choi ◽  
Jaeheum Yeon

2019 ◽  
Vol 27 ◽  
pp. 39-51
Author(s):  
Kamrun N. Keya ◽  
Alamgir Habib ◽  
Sampa Akhter ◽  
Hasan M. Tamim ◽  
Maksuda Akhter

Polymer concrete is one kind of which is used as an additive of the binding material. Due to their high thermal stability, tensile and flexural strengths, high compressive strength and resistance to chemical, its popularity increasing rapidly and which is now widely used as a construction material. This paper explores a research study that has been establishing a standard correlation between concrete compressive strength with the amount of polymers and other ingredients. Hence a comparison was made between the conventional concrete and polymer concrete. As per ASTM C31, the mix design of polymer concrete is calculated and estimated the material quantity. In this research, a total of twenty-two trail mixes of polymer concrete were prepared with different amount of epoxy resin and hardener. In implementation of experimental program compressive strength test was performed for conventional concrete, polymer resin (epoxy resin) concrete with resin percentage 10%, 12%, 15%, 17% and 20% was performed and compared the results with polymer concrete (no-fly ash) with polymer concrete (fly ash) percentage 15%. It was found that the compressive strength of the polymer concrete was increased with increasing the percentage of a polymer. Compressive strength of the 17% and 20% polymer resin-based polymer concrete was 46.75 MPa and 48.32 MPa and cost was around 1,17,110.00 TK and 1,37,152.00 TK; respectively and also it was observed that by using fly ash the strength of the concrete could be increased significantly. It can be said that higher strength can be achieved with a comparatively high cost. However, the cost can be reduced by proper materials selection, mix ratio, curing and adequate quality control of the material.


2019 ◽  
Vol 944 ◽  
pp. 1103-1107
Author(s):  
Ming Dan He ◽  
Ming Li ◽  
Yong Jin Yu ◽  
Hao Wang ◽  
Wei Yuan Xiao ◽  
...  

To adequately understand the waterborne epoxy resin and enhance the compressive, tensile strength of oil-well cement stone, the cement composite materials were prepared with different addition of waterborne epoxy resin, and the specimens were cured for 3days, 7 days, 14days, 28days at 50°C thermostatic water bath to test the compressive strength and tensile strength, respectively. The results showed when the content of resin emulsion is 30%, the compressive strength and tensile strength of the cement are increased by 303.09% and 306.04% compared with pure cement, respectively. Obviously, in the mechanical performance testing, oil-well cement stone modified by waterborne epoxy resin have been significantly improved compared with the pure cement. To explore the enhanced microstructure of oil-well cement modified with waterborne epoxy resin, the cement specimens were prepared with 30% waterborne epoxy resin analyzed by scanning electron microscopy (SEM).


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