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为了研究再生混凝土梁在不同再生粗骨料取代率和不同再生细骨料取代率下其正截面的受力特点和破坏特征,进行了不同再生粗骨料取代率和不同再生细骨料取代率的足尺钢筋混凝土简支梁正截面抗弯性能试验。试验共有7根配筋及构造相同的试件梁,其截面尺寸为300 mm×200 mm,净跨为3 000 mm;再生粗骨料取代率有0%,33%,66%,100%共4种,再生细骨料取代率有0%,50%,100%共3种。试验采用三分点单向重复加载方式,研究了不同再生粗、细骨料取代率对梁的开裂荷载、屈服荷载、极限荷载、挠度、截面应变、裂缝及损伤破坏过程的影响。试验结果表明:再生混凝土梁在正截面受力过程中,仍具有弹性、开裂、屈服和极限4个明显的过程;正截面平均应变服从平截面假定;再生混凝土梁损伤破坏过程与普通混凝土梁相似;相同混凝土和配筋条件下再生混凝土梁的极限承载力与普通混凝土梁接近;再生粗骨料取代率对梁受弯性能影响不明显,而再生细骨料取代率对梁裂缝分布和挠度有一定的影响。
In order to study the stress characteristics and failure characteristics of recycled aggregate concrete beams under different recycled coarse aggregate replacement rates and different recycled fine aggregate substitution rates, the replacement rates of different recycled coarse aggregate and the replacement rates of different recycled fine aggregates Full - scale Bending Behavior of Full - scale Reinforced Concrete Beams. A total of seven test beams with the same reinforcement and the same structure were tested. The cross-sectional dimensions were 300 mm × 200 mm and the net span was 3 000 mm. The replacement rates of recycled coarse aggregate were 0%, 33%, 66% and 100% 4 species, the regeneration of fine aggregate replacement rate of 0%, 50%, 100% total of 3 species. In the experiment, the one-way repeat loading method was used to study the effect of different recycled coarse and fine aggregate substitution rates on the beam cracking load, yield load, ultimate load, deflection, section strain, crack and damage process. The experimental results show that the regenerated concrete beams still have four obvious processes of elasticity, cracking, yielding and ultimate stress in the normal cross-section. The average strain at the normal section follows the assumption of flat section. The damage and destruction process of the recycled concrete beam is similar to ordinary concrete beams. The ultimate bearing capacity of recycled concrete beam is close to that of common concrete beam under the condition of concrete and reinforcement; the effect of replacement rate of recycled coarse aggregate on beam bending performance is insignificant, while the replacement rate of recycled fine aggregate has certain distribution and deflection of beam crack influences.