This paper presents an experimental study on the behavior of circular concrete columns reinforced by BFRP-PVC tubes under uniaxial loading.A total of six specimens were prepared and tested under uniaxial loading.The m...This paper presents an experimental study on the behavior of circular concrete columns reinforced by BFRP-PVC tubes under uniaxial loading.A total of six specimens were prepared and tested under uniaxial loading.The main parameters varied in the tests were strengthening ratio and strengthening approach of BFRP.The performance,such as failure modes,ultimate bearing capacity and stress-strain curves,was investigated in details and a formula was proposed to predict the compressive ultimate strength.The results show that this kind of confined columns obviously improves the ultimate bearing capacity,and the ultimate bearing capacity increases with the strengthening layers.The formula proposed is applicable and efficient for prediction of the ultimate bearing capacity as well.展开更多
We present in this work how to use the dura palm kernel shell powders as loads for the elaboration by extrusion of PVC tubes. The transformation of dura palm kernel shells into micronized shell powder as well as its c...We present in this work how to use the dura palm kernel shell powders as loads for the elaboration by extrusion of PVC tubes. The transformation of dura palm kernel shells into micronized shell powder as well as its characterization was the subject of recent work. We carried out, the formulations by using the industrial scales of precision, the mixtures of the instrants with an industrial machine of mark HENSHLLE N˚2 MAIN 570762, the routine tests by ATG/DSC then by IRTF, the extrusion of the tubes with an extruder twin-screw with 9 rooms of transformation finally the tests of conformity by the observations and the analyses. We obtained for the formulations the dosage of 0%, 4.01%, 12.54%, 23.03%, 32.01%, 38.01%, 51.02% representing the percentage of hull powder in the mixture, the machine mixing gave perfectly homogeneous powders, the routine tests showed that the hull powder keeps all its properties until the end of the shaping whatever the percentage of hulls contained in the PVC, the extrusion gave tubes for each formulation and the conformity tests gave perfectly round tubes of diameter 90 × 82 mm, a coloration going from white grey at 0% to dark black at 51.02% showing the influence of the carbon black and the color of the shell powder according to its proportion. The infrared of the tubes obtained shows for each formulation a variation of the CH<sub>2</sub> and CH bonds and a decrease of the −OH bonds. The thermogravimetric analyses and the differential calorimetric analyses of the tubes of each formulation, show each time that the quantity of shell powders in the mixture influences the PVC tubes obtained. Thus, we obtain a variation of the phase temperatures according to the dosage, giving from 108.72<span style="white-space:normal;">˚</span>C to 76.56<span style="white-space:normal;">˚</span>C for the glass transition temperature and from 494.71<span style="white-space:normal;">˚</span>C to 414.56<span style="white-space:normal;">˚</span>C for the melting temperature, at the DSC and a progressive decrease of the mass following the heat absorption with each time 4 phases instead of 5 for the unloaded PVC tubes at the ATG according to the dosage.展开更多
文摘This paper presents an experimental study on the behavior of circular concrete columns reinforced by BFRP-PVC tubes under uniaxial loading.A total of six specimens were prepared and tested under uniaxial loading.The main parameters varied in the tests were strengthening ratio and strengthening approach of BFRP.The performance,such as failure modes,ultimate bearing capacity and stress-strain curves,was investigated in details and a formula was proposed to predict the compressive ultimate strength.The results show that this kind of confined columns obviously improves the ultimate bearing capacity,and the ultimate bearing capacity increases with the strengthening layers.The formula proposed is applicable and efficient for prediction of the ultimate bearing capacity as well.
文摘We present in this work how to use the dura palm kernel shell powders as loads for the elaboration by extrusion of PVC tubes. The transformation of dura palm kernel shells into micronized shell powder as well as its characterization was the subject of recent work. We carried out, the formulations by using the industrial scales of precision, the mixtures of the instrants with an industrial machine of mark HENSHLLE N˚2 MAIN 570762, the routine tests by ATG/DSC then by IRTF, the extrusion of the tubes with an extruder twin-screw with 9 rooms of transformation finally the tests of conformity by the observations and the analyses. We obtained for the formulations the dosage of 0%, 4.01%, 12.54%, 23.03%, 32.01%, 38.01%, 51.02% representing the percentage of hull powder in the mixture, the machine mixing gave perfectly homogeneous powders, the routine tests showed that the hull powder keeps all its properties until the end of the shaping whatever the percentage of hulls contained in the PVC, the extrusion gave tubes for each formulation and the conformity tests gave perfectly round tubes of diameter 90 × 82 mm, a coloration going from white grey at 0% to dark black at 51.02% showing the influence of the carbon black and the color of the shell powder according to its proportion. The infrared of the tubes obtained shows for each formulation a variation of the CH<sub>2</sub> and CH bonds and a decrease of the −OH bonds. The thermogravimetric analyses and the differential calorimetric analyses of the tubes of each formulation, show each time that the quantity of shell powders in the mixture influences the PVC tubes obtained. Thus, we obtain a variation of the phase temperatures according to the dosage, giving from 108.72<span style="white-space:normal;">˚</span>C to 76.56<span style="white-space:normal;">˚</span>C for the glass transition temperature and from 494.71<span style="white-space:normal;">˚</span>C to 414.56<span style="white-space:normal;">˚</span>C for the melting temperature, at the DSC and a progressive decrease of the mass following the heat absorption with each time 4 phases instead of 5 for the unloaded PVC tubes at the ATG according to the dosage.
