Size Effects in Climatic Aging of Epoxy Basalt Fiber Reinforcement Bar
Anna A Gavrilieva1, Oleg V Startsev1,2, Mikhail P Lebedev2
1Siberian Branch of the Russian Academy of Sciences V.P. Larionov Institute of Physical and Technical Problems of the North, 1 Oktyabrskaya Str., 677000 Yakutsk, Russia.
Polymers
|September 28, 2024
Summary
The size of pultruded epoxy basalt fiber reinforcement bars significantly impacts their climatic aging. Smaller diameter bars experience greater moisture effects and strength reduction, while larger bars show less degradation, highlighting the importance of size in material durability.
Area of Science:
- Materials Science
- Polymer Science
- Composite Materials
Background:
- Pultruded composite materials, such as epoxy basalt fiber reinforcement bars, are susceptible to environmental degradation.
- Climatic aging, particularly moisture absorption and temperature fluctuations, can significantly alter material properties.
- Understanding the influence of material dimensions on aging is crucial for predicting long-term performance.
Purpose of the Study:
- To investigate the effect of bar diameter on the climatic aging of pultruded epoxy basalt fiber reinforcement bars.
- To analyze the kinetics of moisture transfer and its impact on material properties under different climatic conditions.
- To determine how size influences mechanical strength, thermal expansion, and glass transition temperature after prolonged environmental exposure.
Main Methods:
- Samples of epoxy basalt fiber reinforcement bars with varying diameters (6-20 mm) were exposed to extreme cold (Yakutsk) and moderate warm (Gelendzhik) climates for 28-54 months.
- Moisture transfer kinetics were studied using humidification and drying at 60 °C, modeled with the 2D Langmuir model.
- Mechanical properties (tensile, compressive, bending strength), coefficient of linear thermal expansion, and glass transition temperature were measured after exposure.
Main Results:
- Diffusion coefficients were significantly higher in the reinforcement direction than the radial direction, varying with bar diameter.
- Moisture penetration had a more significant impact on the strength of smaller diameter bars (6 mm) compared to larger ones.
- Smaller diameter bars showed decreased deformability and a more significant increase in glass transition temperature, indicating greater aging effects and additional polymer matrix curing.
Conclusions:
- Bar diameter is a critical factor influencing the climatic aging of pultruded epoxy basalt fiber reinforcement bars.
- Moisture plasticization significantly reduces the strength of smaller diameter bars, while larger bars are less affected.
- The observed increase in glass transition temperature in smaller bars suggests enhanced polymer matrix curing due to moisture interaction and thermal cycling.
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