Creep behavior of resin matrix and basalt fiber reinforced polymer (Bfrp) plate at elevated temperatures

Pre-stressed fiber reinforced polymer (FRP) has great application potential in structural strengthening. However, the elevated temperature resistance of FRPs is always a key concern due to the poor thermal stability of its resin matrix. In this study, the effects of temperature on the creep behavior of the resin matrix and basalt fiber reinforced polymer (BFRP) was experimentally investigated. The tensile stresses were set at 2.6 MPa for the resin matrix and 522 MPa (35% of its ultimate tensile strength (f_u )) for BFRP, and the exposure temperatures were 25^◦ C, 80^◦ C, 120^◦ C, and 160^◦ C. The short-term strain of the resin matrix and BFRP exposed to different exposure temperatures was measured. The variation of the thermal property and interlaminar shear strength (ILSS) of the BFRP were studied. The results indicated that molecular chain disruption and post-cure coexisted. The resin matrix is sensitive to the exposure temperatures, and a remarkable increase of the strain was observed when the exposure temperature exceeded its glass transition temperature (107.5^◦ C). The resin matrix fractured within 50 seconds when it was exposed to 160^◦ C. BFRP showed excellent temperature resistance even though the exposure temperature exceeded its glass transition temperature (123.7^◦ C). Sustained loading led to stress transferring to the basalt fiber in BFRP specimens, especially at elevated temperatures. Stress redistribution caused interfacial damage, and ILSS decreased by 0.5%, 13.6%, and 14.6% for 80^◦ C, 120^◦ C, and 160^◦ C exposure from its original value of 73.5 MPa. Dynamic mechanical thermal analysis (DMTA) was used to explain the post-curing and interface damage of BFRP.