Flexural behaviour of concrete beams pretensioned with aramid fibre reinforced plastic tendons

1993 ◽  
Vol 20 (4) ◽  
pp. 688-695 ◽  
Author(s):  
K. S. McKay ◽  
M. A. Erki
Keyword(s):  
Cyclic Loading ◽  
Prestressed Concrete ◽  
Concrete Structures ◽  
Aramid Fibre ◽  
Advanced Composite ◽  
Advanced Composite Materials ◽  
Reinforced Plastic ◽  
Aramid Fibres ◽  
Static And Cyclic Loading ◽  
Corrosive Environments

The durability of reinforced concrete structures has become an increasing concern as our infrastructure ages. In particular is the deterioration of steel reinforcements when used in concrete structures exposed to severe corrosive environments. This paper investigates the feasibility of using noncorroding aramid fibre reinforced plastic (AFRP) tendons as a substitute for steel strand in pretensioned concrete applications. Three AFRP pretensioned beams, 150 × 300 × 2100 mm, were tested under static and cyclic loading. These results indicate that load capacities of the beams were not affected by the cyclic loading. Ultimate strengths were generally greater than predicted, primarily as a result of the ability of the AFRP rods to develop greater tensile stresses than expected. Key words: prestressed concrete, nonmetallic tendons, aramid fibres, advanced composite materials.

Grouted anchorages for aramid fibre reinforced plastic prestressing tendons

1993 ◽  
Vol 20 (6) ◽  
pp. 1065-1069 ◽  
Author(s):  
K. S. McKay ◽  
M. A. Erki
Keyword(s):  
Prestressed Concrete ◽  
Steel Tube ◽  
High Ratio ◽  
Aramid Fibre ◽  
Test Results ◽  
Structural Deterioration ◽  
Reinforced Composite ◽  
Reinforced Plastic ◽  
Aramid Fibres ◽  
Lateral Strength

Nonmetallic prestressing tendons, made of fibre-reinforced composite materials, are being proposed as alternatives to steel prestressing tendons for bridges and parking garage structures, where corrosion is the leading cause of structural deterioration. One type of commercially available nonmetallic tendons is made of pultruded aramid fibres. One of the main problems for these tendons, which is common to all nonmetallic tendons, is that the high ratio of the axial to lateral strength of fibre-reinforced materials requires special attention to the type of anchorage used. For the aramid tendon, the simplest grouted anchorage consists of a steel tube filled with nonshrink grout, into which the end of the tendon is embedded. This note presents the test results of a parametric study on grouted anchorages for pultruded aramid tendons. Key words: prestressed concrete, nonmetallic tendons, aramid fibre, grouted anchorage.

Comprehensive investigation of cutting mechanisms and hole quality in dry drilling woven aramid fibre–reinforced plastic with typical tools

2019 ◽  
Vol 233 (14) ◽  
pp. 2471-2491 ◽  
Author(s):  
Sinan Liu ◽  
Tao Yang ◽  
Chang Liu ◽  
Yu Du
Keyword(s):  
Radial Component ◽  
Aramid Fibre ◽  
Twist Drill ◽  
Hole Quality ◽  
Specific Strength ◽  
Reinforced Plastics ◽  
Dry Drilling ◽  
Reinforced Plastic ◽  
Aramid Fibres ◽  
Cutting Mechanisms

Due to high specific strength and strong toughness, aramid fibre–reinforced plastics have been widely used in the aircraft, military, and automobile industries. However, in the hole-making process, these excellent properties make aramid fibre–reinforced plastics difficult to machine and prone to severe entrance and exit damages. In this article, the cutting mechanisms of three typical tools (twist drill, burr tool, and brad drill) are thoroughly investigated during dry drilling of aramid fibre–reinforced plastic. On this basis, systematic experiments are conducted to evaluate the cutting performance and hole quality. At the hole entrance, the cutting edges of the twist drill peel and tear the uncut material, which results in severe fuzzing damage. Due to the radial rake angles of the burr tool and brad drill, the radial component of the cutting force can pre-tension aramid fibres prior to being cut, which effectively reduces the fuzzing defect. At the hole exit, the extrusion action of the chisel edge and the severe chip adherence are the main causes of exit damage for the twist drill and burr tool, respectively. Due to the decrease in the thrust force and improvement in the shearing action, the best hole quality is achieved by the brad drill. To further improve the hole quality, an auxiliary approach using collars is introduced to effectively restrain the damage by enhancing interfacial bonding strength. This article provides comprehensive and available information on tool performance for drilling aramid fibre–reinforced plastics, which can help guide process optimizations to achieve the desired hole quality.

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