ASTM D3647 Standard Practice for Classifying Reinforced Plastic Pultruded Shapes According to Composition (Withdrawn 2022)

ASTM D3647 Introduction

ASTM D3647 was a recognized practice that defines and classifies these products based on their composition, which helps in the specification, design, and selection of materials. The product A pultruded shape is produced by continuous pulling of resin-wet fibers through a heated die, which is used in structural or industrial applications. The classification was based on the nature of the resin and reinforcement, thereby providing a harmonized approach to glazing and comparing materials as used by suppliers and in various applications.

ASTM D3647 Test Method

ASTM D3647 Equipment and Sample Preparation

ASTM D3647 Results and Interpretation

This method includes a classification code that identifies the resin type and reinforcement content. As an example, a pultruded form in vinyl ester resin and reinforced with glass fiber would belong in a category that would be assigned its anticipated performance attributes. Such classifications provided users with insight into the typical performance of a product, eliminating the need for comprehensive testing.

ASTM D3647 Related Test Methods

ASTM D790 is employed to assess flexural strength and hardness. Impact resistance, which is crucial for applications subjected to sudden loads or shocks, is evaluated using ASTM D256.

ASTM D3647 Applications and Industry Use

The construction, transportation, marine, and electrical industries have leveraged pultruded composites due to their exceptional corrosion resistance, strength-to-weight ratio, and dimensional stability. This method was particularly helpful in standardizing the selection of materials for structural applications, such as ladder rails, cable trays, and grating supports.

ASTM D3647 Materials Commonly Tested

The materials that fall under this method are pultruded shapes made from thermosetting resin systems, such as polyester, vinyl ester, and epoxy, which are typically durable, resistant to chemicals, and possess a strong structural integrity. These resins are used in conjunction with fiber reinforcements, such as glass fiber, carbon fiber, and aramid, to enhance the mechanical properties, including tensile strength, stiffness, and impact resistance, of the resins.

ASTM D3647 Common Challenges and Troubleshooting

One of the shortcomings of the standard was that the dependency on the composition data did not demand that the performance be verified on all the products. This sometimes caused conflicts between the rated type and reality, and it paid off to have the confirmatory test done using referenced methods.

ASTM D3647 Safety and Best Practices

Pultruded composites can be dangerous to handle as they have exposure to raw fibers on the skin. Gloves, safety glasses, and a dust mask are the proper PPE to wear to prevent fiber dust in the air when the sample is to be cut up and retested.

ASTM D3647 Importance 

This method has made a significant historical contribution to the classification of pultruded composite materials and has played a substantial role in the development of standard practice. It provided a shared vocabulary between material manufacturers and designers, enabling them to select materials and communicate effectively in an industry where unusual formulations are commonplace.