Loading...
Durability Study of Basalt Fiber-reinforced Bars Exposed to Harsh Environments
Alrifai, Mohamad Mazen
Alrifai, Mohamad Mazen
Description
A Master of Science thesis in Civil Engineering by Mohamad Mazen Alrifai entitled, “Durability Study of Basalt Fiber-reinforced Bars Exposed to Harsh Environments”, submitted in April 2019. Thesis advisor is Dr. Farid Abed and thesis co-advisor is Dr. Tamer El Maaddawy. Soft and hard copy available.
Abstract
In this research, the durability of Basalt Fiber Reinforced Polymers (BFRP) bars of 10 mm diameter is studied after direct exposure to severe conditions. The main aim is to investigate the degradation performance of the microstructure and tensile properties of these BFRP bars under accelerated conditionings that simulate the concrete’s environment. A set of BFRP bars was wrapped by concrete prisms that were immersed in tap water. Another set of BFRP bars was exposed to alkaline solution. In concrete-wrapped and alkaline exposures, temperatures of 20oC, 40oC, 60oC were applied in isolated tanks for durations of 2880, 5760, and 8760 hours. The experimental program included Uniaxial Tensile Tests, Scanning Electron Microscopy (SEM), Water Absorption, Differential Scanning Calorimetry Analysis (DSC), Fourier Transform Infrared Spectrometry (FTIR), Matrix Digestion, and Fiber Volume Fraction Analysis. This combination of tests was selected to validate the tensile strength values. The output of these tests is a comprehensive microstructural characterization and tensile behavior evaluation before and after exposure to harsh environments. As a result, the effect of temperature was more distinct than the effect of exposure periods. Higher temperatures and greater durations in a harsh environment tend to cause impairments on the structural and microstructural levels. These impairments are represented by tensile loss, debonding, matrix loss, moisture impregnation, and micro-cracking at the fiber-matrix interface. Maximum tensile loss, moisture loss, and matrix loss were recorded to be 29%, 1%, 29.8%, respectively, for the samples that were conditioned for 9 months at 60oC in alkaline environment.