Evaluation of a New Bond-Type Anchorage System with Expansive Grout for a Single FRP Rod

Prestressed concrete applications require a high strength prestressing material that could apply and maintain effective compressive force to concrete members. Although fiber reinforced polymer (FRP) materials, especially carbon FRP (CFRP), have the desired strength, no efficient system for its anchorage to concrete has been devised yet. This paper presents an experimental evaluation on a new bond-type anchorage system using an expansive grout as a filling material to anchor CFRP rods. A total of twelve specimens were fabricated and tested. Short-term and long-term pullout tests were performed. The CFRP rods were 0.375 in. (10 mm) and 0.50 in. (13 mm) in diameter. The parameters investigated were the bond length, rod diameter, and curing time of the expansive grout. The experimental results showed that 12 in. (305 mm) and 15 in. (381 mm) were adequate bond lengths to effectively anchor the 0.375 in. (10 mm) and 0.50 in. (13 mm) CFRP rods, respectively. The results also indicated that the anchor strength and stiffness were directly proportional to the bond length, and cross-sectional area ratio of CFRP rods to anchor borehole affected the stiffness and bonding capacity of the proposed anchor. Finally, a numerical analysis was carried out to predict the tensile behavior of FRP anchors. The numerical results had good agreement with the experimental results

Evaluation of a new bond-type anchorage system with expansive grout for a single FRP rod

Prestressed concrete applications require a high strength prestressing material that could apply and maintain effective compressive force to concrete members. Although fiber reinforced polymer (FRP) materials, especially carbon FRP (CFRP), have the desired strength, no efficient system for its anchorage to concrete has been devised yet. This paper presents an experimental evaluation on a new bond-type anchorage system using an expansive grout as a filling material to anchor CFRP rods. A total of twelve specimens were fabricated and tested. Short-term and long-term pullout tests were performed. The CFRP rods were 0.375 in. (10 mm) and 0.50 in. (13 mm) in diameter. The parameters investigated were the bond length, rod diameter, and curing time of the expansive grout. The experimental results showed that 12 in. (305 mm) and 15 in. (381 mm) were adequate bond lengths to effectively anchor the 0.375 in. (10 mm) and 0.50 in. (13 mm) CFRP rods, respectively. The results also indicated that the anchor strength and stiffness were directly proportional to the bond length, and cross-sectional area ratio of CFRP rods to anchor borehole affected the stiffness and bonding capacity of the proposed anchor. Finally, a numerical analysis was carried out to predict the tensile behavior of FRP anchors. The numerical results had good agreement with the experimental results

Physicochemical study of eco-friendly sugar palm fiber thermoplastic polyurethane composites

The physicochemical properties of an innovative and environmentally friendly composite material based on sugar palm fiber (SPF) and thermoplastic polyurethane (TPU) were examined. The base material with short fibers was extruded and hot pressed to produce the TPU-SPF composites with different synthetic parameters. Operating parameters including temperature for extrusion (170 to 190 °C), rotational velocity (30 to 50 rpm), and fiber particle sizes (160, 250, and 425 µm) were investigated. The aims were to optimize rotational velocity, temperature, and fiber size of the TPU-SPF composites. Firstly, the influence of rotation of velocity and temperature on the tensile properties was investigated. Secondly, effects of different fiber sizes on tensile, flexural properties, and impact strength as per ASTM standards were tested. The morphological, thermal, and physicochemical properties of the synthesized TPU-SPF composites were ascertained with Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The optimal results were observed with a temperature of 190°C and a rotational velocity of 40 rpm. Meanwhile, the strength and modulus for tensile and flexural were best for fiber size 250 µm. Moreover, the impact strength reached a peaking trend at 250 µm fiber siz

Removal of Cd(II) from Aqueous Solution Using Blue Pine Sawdust: Equilibrium, Kinetics and Thermodynamic Studies

The adsorption of Cd(II) ions onto sawdust has been investigated in detail as a function of equilibration time (1-120 min), dosage of adsorbent (0.025-0.5 g)/10 ml, concentration of Cd(II) (9-1780 mu M) and of nature (pH 1-10). Maximum adsorption (ca. 95.3%) is achieved from deionised water in 30 minutes at pH 7 using 0.2 g adsorbent/10 ml adsorbate solution. The adsorption data follow Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms over the entire range of Cd(II) ions concentration examined and their characteristic constants have also been evaluated. The variation of adsorption with temperature has yielded Delta H, Delta S and Delta G values for the 18 mu M cadmium concentration. The kinetics of adsorption obeys Morris-Weber and Lagergren equations. The first order rate constant and the intraparticle diffusion rate have also been estimated. Sawdust appears to have potential to remove Cd(II) ions from aqueous solutions at trace or subtrace concentration, to preconcentrate or treat industrial wastewater