AFRP-水泥砂浆抗弯性能的湿热效应

Influence of Moisture and Heat on the Bending Property of AFRP-Cement Mortar

利用三点弯曲试验研究了不同湿热条件下外贴芳纶纤维增强塑料(AFRP)片材水泥砂浆试件抗弯性能的变化.结果表明:当AFRP-水泥砂浆试件在25°C水中浸泡1～5d,其抗弯断裂荷载随时间的增加基本不变,但显著低于室温干燥条件下的抗弯断裂荷载;当试件在60°C水中浸泡1～5d,其抗弯断裂荷载随时间的增加而逐渐上升;当试件在90°C水中浸泡1～5d,相应的抗弯断裂荷载随时间的增加呈先增大后减小趋势.当试件在25°C和60°C水中浸泡1～5d,AFRP-水泥砂浆试件断裂破坏模式为具有一定延性的积累性破坏;当在90°C水中浸泡1～3d,其破坏模式保持不变,但继续浸泡到5d时,由于试件发生了严重的界面剥离破坏,则该破坏模式转变为脆性破坏.上述研究结果仅对所采用的树脂体系有效.

The change of bending property for AFRP-cement mortar in different moisture and heat conditions was studied. When the specimen was immersed in 25°C water for 1-5 d, the bending failure load did not change with the time, but it is obviously lower than that under the dry and room temperature condition. When the specimen was immersed in 60°C water for 1-5 d, the bending failure load increased with the time. When the specimen was immersed in 90°C water for 1-5 d, the bending failure load increased at 1-3 d, but decreased after 3 d. The fracture modes of AFRP-cement mortar were accumulation with ductility when they were immersed in 25°C and 60°C water for 1-5 d, as well as 1-3 d at 90°C. But when they were immersed in 90°C water for 5 d, the brittle collapse took place due to serious pearling damage of interphase. The results are only effective for the resin system used in the experiment.