The Experts below are selected from a list of 95331 Experts worldwide ranked by ideXlab platform

Ahmed El Refai - One of the best experts on this subject based on the ideXlab platform.

  • bond durability of basalt fiber reinforced Polymer bars embedded in concrete under direct pullout conditions
    Journal of Composites for Construction, 2015
    Co-Authors: Ahmed El Refai, Farid Abed, Ahmad Altalmas
    Abstract:

    AbstractThe use of basalt fiber–reinforced Polymer (BFRP) bars as a reinforcing material has gained increasing interest worldwide. However, few studies have reported on these bars’ performance in concrete when exposed to harsh environments. This paper investigates the effect of five different accelerated environments, namely (1) tap water, (2) seawater, (3) elevated temperature, (4) elevated temperature followed by tap water, and (5) elevated temperature followed by seawater, on the bond stress-slip response, adhesion to concrete, and bond strength [of two types of BFRP bars and one type of glass fiber–reinforced Polymer (GFRP) bar]. The bond-slip responses of all specimens were governed by the surface treatment of each bar and its manufacturing quality, regardless of the fiber type. Sand-coated BFRP bars showed higher bond characteristics than helically grooved bars after conditioning. Moister environments caused enhanced adhesion at the early loading stages for all specimens. Nevertheless, such environm...

  • bond performance of basalt fiber reinforced Polymer bars to concrete
    Journal of Composites for Construction, 2015
    Co-Authors: Ahmed El Refai, Mohamed Ammar, Radhouane Masmoudi
    Abstract:

    This paper presents the test results of a study on the bond behavior of basalt Fiber-Reinforced Polymer (BFRP) bars to concrete. Thirty six concrete cylinders reinforced with BFRP bars and twelve cylinders reinforced with glass Fiber-Reinforced Polymer (GFRP) bars were tested in direct pullout conditions. Test parameters included the FRP material (basalt and glass), the bar diameter, and the bar embedment length in concrete. Bond-slip curves of BFRP and GFRP bars revealed similar trends. BFRP bars developed average bond strength 75% of that of GFRP bars. All BFRP specimens failed in a pullout mode of failure along the interfacial surface between the outer layer of the bar and the subsequent core layers. The influence of various parameters on the overall bond performance of BFRP bars is analyzed and discussed. The well-known BPE and modified-BPE analytical models were calibrated to describe the bond-slip relationships of the bars. Test results demonstrate the promise of using the BFRP bars as an alternative to the GFRP bars in reinforcing concrete elements.

  • bond degradation of basalt fiber reinforced Polymer bfrp bars exposed to accelerated aging conditions
    Construction and Building Materials, 2015
    Co-Authors: Ahmad Altalmas, Ahmed El Refai, Farid Abed
    Abstract:

    Abstract Bond durability of sand-coated basalt Fiber-Reinforced Polymer (BFRP) bars was investigated. Pullout specimens were tested under direct tensile load after being exposed to accelerated conditioning environments. The test parameters included the bar material (basalt and glass), the conditioning environment (acid, saline, and alkaline), and the duration of exposure (30, 60, and 90 days). The bond behavior of the tested specimens was reported in terms of stress–slip response, bond strength, bar slip, adhesion, and failure mechanism. The BFRP bars showed higher adhesion and bond strengths to concrete than the ribbed glass Fiber-Reinforced Polymer (GFRP) bars irrespective of the fiber type and the exposure condition. The absorption of the bar material and its quality of manufacturing affected the bond behavior of the conditioned specimens. All specimens failed in pullout mode by inter-laminar shear between the layers of the bar. Conditioning reduced the bond strength of the BFRP bars by 14–25% of their initial strength. Ribbed GFRP specimens subjected to acid exposure suffered the highest loss in bond strength (25%) compared to 17% for GFRP specimens exposed to alkaline and ocean water. Conditioning had insignificant influence on the slip of the bars.

Ahmad Altalmas - One of the best experts on this subject based on the ideXlab platform.

  • bond durability of basalt fiber reinforced Polymer bars embedded in concrete under direct pullout conditions
    Journal of Composites for Construction, 2015
    Co-Authors: Ahmed El Refai, Farid Abed, Ahmad Altalmas
    Abstract:

    AbstractThe use of basalt fiber–reinforced Polymer (BFRP) bars as a reinforcing material has gained increasing interest worldwide. However, few studies have reported on these bars’ performance in concrete when exposed to harsh environments. This paper investigates the effect of five different accelerated environments, namely (1) tap water, (2) seawater, (3) elevated temperature, (4) elevated temperature followed by tap water, and (5) elevated temperature followed by seawater, on the bond stress-slip response, adhesion to concrete, and bond strength [of two types of BFRP bars and one type of glass fiber–reinforced Polymer (GFRP) bar]. The bond-slip responses of all specimens were governed by the surface treatment of each bar and its manufacturing quality, regardless of the fiber type. Sand-coated BFRP bars showed higher bond characteristics than helically grooved bars after conditioning. Moister environments caused enhanced adhesion at the early loading stages for all specimens. Nevertheless, such environm...

  • bond degradation of basalt fiber reinforced Polymer bfrp bars exposed to accelerated aging conditions
    Construction and Building Materials, 2015
    Co-Authors: Ahmad Altalmas, Ahmed El Refai, Farid Abed
    Abstract:

    Abstract Bond durability of sand-coated basalt Fiber-Reinforced Polymer (BFRP) bars was investigated. Pullout specimens were tested under direct tensile load after being exposed to accelerated conditioning environments. The test parameters included the bar material (basalt and glass), the conditioning environment (acid, saline, and alkaline), and the duration of exposure (30, 60, and 90 days). The bond behavior of the tested specimens was reported in terms of stress–slip response, bond strength, bar slip, adhesion, and failure mechanism. The BFRP bars showed higher adhesion and bond strengths to concrete than the ribbed glass Fiber-Reinforced Polymer (GFRP) bars irrespective of the fiber type and the exposure condition. The absorption of the bar material and its quality of manufacturing affected the bond behavior of the conditioned specimens. All specimens failed in pullout mode by inter-laminar shear between the layers of the bar. Conditioning reduced the bond strength of the BFRP bars by 14–25% of their initial strength. Ribbed GFRP specimens subjected to acid exposure suffered the highest loss in bond strength (25%) compared to 17% for GFRP specimens exposed to alkaline and ocean water. Conditioning had insignificant influence on the slip of the bars.

Farid Abed - One of the best experts on this subject based on the ideXlab platform.

  • bond durability of basalt fiber reinforced Polymer bars embedded in concrete under direct pullout conditions
    Journal of Composites for Construction, 2015
    Co-Authors: Ahmed El Refai, Farid Abed, Ahmad Altalmas
    Abstract:

    AbstractThe use of basalt fiber–reinforced Polymer (BFRP) bars as a reinforcing material has gained increasing interest worldwide. However, few studies have reported on these bars’ performance in concrete when exposed to harsh environments. This paper investigates the effect of five different accelerated environments, namely (1) tap water, (2) seawater, (3) elevated temperature, (4) elevated temperature followed by tap water, and (5) elevated temperature followed by seawater, on the bond stress-slip response, adhesion to concrete, and bond strength [of two types of BFRP bars and one type of glass fiber–reinforced Polymer (GFRP) bar]. The bond-slip responses of all specimens were governed by the surface treatment of each bar and its manufacturing quality, regardless of the fiber type. Sand-coated BFRP bars showed higher bond characteristics than helically grooved bars after conditioning. Moister environments caused enhanced adhesion at the early loading stages for all specimens. Nevertheless, such environm...

  • bond degradation of basalt fiber reinforced Polymer bfrp bars exposed to accelerated aging conditions
    Construction and Building Materials, 2015
    Co-Authors: Ahmad Altalmas, Ahmed El Refai, Farid Abed
    Abstract:

    Abstract Bond durability of sand-coated basalt Fiber-Reinforced Polymer (BFRP) bars was investigated. Pullout specimens were tested under direct tensile load after being exposed to accelerated conditioning environments. The test parameters included the bar material (basalt and glass), the conditioning environment (acid, saline, and alkaline), and the duration of exposure (30, 60, and 90 days). The bond behavior of the tested specimens was reported in terms of stress–slip response, bond strength, bar slip, adhesion, and failure mechanism. The BFRP bars showed higher adhesion and bond strengths to concrete than the ribbed glass Fiber-Reinforced Polymer (GFRP) bars irrespective of the fiber type and the exposure condition. The absorption of the bar material and its quality of manufacturing affected the bond behavior of the conditioned specimens. All specimens failed in pullout mode by inter-laminar shear between the layers of the bar. Conditioning reduced the bond strength of the BFRP bars by 14–25% of their initial strength. Ribbed GFRP specimens subjected to acid exposure suffered the highest loss in bond strength (25%) compared to 17% for GFRP specimens exposed to alkaline and ocean water. Conditioning had insignificant influence on the slip of the bars.

Saverio Spadea - One of the best experts on this subject based on the ideXlab platform.

Qiang Cheng - One of the best experts on this subject based on the ideXlab platform.

  • microwave curing of multidirectional carbon fiber reinforced Polymer composites
    Composite Structures, 2019
    Co-Authors: Jing Zhou, Qiang Cheng
    Abstract:

    Abstract Composite microwave curing technologies have been researched and given great expectations for decades to cutting down the long curing cycle and enormous energy consumption during traditional curing process. However, this good vision was stopped since the microwave can hardly penetrate and heat multidirectional carbon fiber reinforced Polymer composites. In this paper, the mechanism that multidirectional composite can hardly be heated was revealed. New method was found to stimulate Vertical Penetrating Microwave (VPM) by using metal strips, and the multidirectional carbon fiber reinforced Polymer composites can be heated directly. The theory and model of VPM’s heating depth of multidirectional composite were established and verified. The results indicated that 2.3 mm thickness multidirectional composite can be cured effectively by using the VPM.