GFRP筋海砂混凝土梁受弯性能试验研究

EXPERIMENTAL RESEARCH ON FLEXURAL PERFORMANCE OF GFRP BAR REINFORCING SEA SAND CONCRETE BEAM

河砂过度开采对生态环境造成了严重的影响,用海砂代替传统混凝土中的河砂,可以解决河砂资源缺乏的问题。但是海砂中含有大量的氯离子,对钢筋具有很强的腐蚀性,而纤维增强复合材料(Fiber reinforced polymer,FRP)具有优良的耐腐蚀性,能很好地与海砂混凝土共同工作。为探索GFRP筋海砂混凝土梁受弯性能,文中对4根GFRP筋海砂混凝土梁进行受弯试验,获得混凝土强度和配筋率对海砂混凝土梁的裂缝发展、开裂荷载和极限荷载的影响规律,结果表明提高混凝土的强度等级,对开裂荷载有显著的提升;试验梁的配筋率接近界限配筋率时,混凝土强度等级对极限荷载没有影响,同时试验梁以纯弯段为主裂缝;当配筋率远大于界限配筋率时,提高混凝土强度等级,试验梁的极限荷载有明显的提升,同时试验梁以斜裂缝为主裂缝,通过试验为GFRP筋海砂混凝土梁的设计提供参考。

At this stage,river sand has been over-exploited,which has had a serious impact on the ecological environment.Substituting sea sand for the river sand in traditional concrete can solve the problem of the increasingly scarce river sand resources.The sea sand contains a large amount of chloride ions and is highly corrosive to steel bar,while fiber reinforced polymer(FRP)has excellent corrosion resistance and can be well combined with sea sand concrete.In order to explore the flexural performance of GFRP reinforced sea sand concrete beams,4 GFRP reinforced sea sand concrete beams were subjected to bending tests to obtain the influence of concrete strength and reinforcement ratio on the crack development,cracking load and ultimate load of sea sand concrete beams.The results show that increasing the strength level of concrete can significantly increase the cracking load;when the reinforcement ratio of the test beam is close to the limit reinforcement ratio,the concrete strength level has no effect on the ultimate load.At the same time,the test beam has a pure bending section as the main crack;When the reinforcement ratio is much greater than the limit reinforcement ratio,increase the concrete strength grade,the ultimate load of the test beam is significantly improved,and the test beam is mainly cracked;the test provides for the design of the GFRP reinforced sea sand concrete beam reference.