In order to study the retrofitting effects of hybrid fiber reinforced reactive powder concrete ( HFRPC) ,the flexural behaviour of reinforced concrete ( RC) beams reinforced with HFRPC was investigated by experiment and theory, then compared with reinforced concrete beams without retrofitting. Seven test beams were designed and made, one of which was not retrofitted, while the other 6 were retrofitted with HFRPC. The test variables include thickness of HFRPC, HFRPC and concrete interfacial bonding method, retrofitting fiber, and so on. The test re-sults show that the reinforced concrete beam strengthened with HFRPC exhibits improved bearing capacity and de-creased deformation. The HFRPC retrofitting layer bonds well with concrete, no debonding failure happens. While there are numerous cracks on the HFRPC reinforcement layer, crack width is significantly decreased.Gouged beams have larger bearing capacity than those with troughs. The superior performance of high-strength steel set in HFRPC is fully utilized. Beams with a 40 mm thickness retrofitting layer have larger capacity than 30 mm beams, about 5%better flexural performance. Adopting fiber cloth wraps to retrofit new and old concrete beams can effectively prevent crack propagation, and thus slowing down loss of ultimate load bearing capacity. Through theoretical analysis, a for-mula for the calculation of HFRPC beam crack load, yield load, and ultimate load is provided. Finally,the experi-mental results match well with the theoretical predictions.%为了研究混杂纤维增强活性粉末混凝土(HFRPC)的加固效果,进行了高强钢筋HFRPC加固普通钢筋混凝土梁抗弯性能的试验和理论研究,并与未加固梁比较. 共完成7根梁抗弯试验,其中1根是未加固梁,6根为HFRPC加固梁. 变化参数为:HFRPC厚度、HFRPC与旧混凝土界面粘结方式和粘贴纤维布等. 试验结果表明:采用高强钢筋HFRPC加固梁能有效提高抗弯承载力,HFRPC加固层与旧混凝土粘结牢靠,未发生脱粘破坏;HFRPC加固层裂缝数量众多、宽度明显减小;旧混凝土表面经凿坑处理比凿沟处理的加固梁承载力更大;HFRPC中配置高强钢筋,能发挥高强钢筋优势;HFRPC加固层厚度40 mm比30 mm梁抗弯承载力提高5%;采用纤维布箍约束新旧混凝土,可阻止弯曲裂缝扩展,峰值荷载后承载力下降较慢. 最后,给出了加固梁开裂荷载、屈服荷载和极限承载力计算公式,计算值与试验结果吻合较好.
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