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再生混凝土构件受力分析的关键问题是钢筋与再生混凝土间的黏结滑移本构关系。进行了49个钢筋与再生混凝土试件黏结滑移性能的试验研究。试件尺寸为150 mm×150 mm×450 mm,钢筋直径d分别为10、14、20 mm,钢筋外形分为螺纹钢筋、光圆钢筋,钢筋锚固长度分为5d、10d、20d,混凝土再生粗骨料取代率分别为33%、66%、100%,再生细骨料取代率分别为50%、100%,混凝土设计强度分为中强和高强。试验研究表明:再生粗细骨料取代率及混凝土强度、钢筋外形、钢筋锚固长度为影响试件黏结滑移性能的关键因素;再生细骨料取代率50%以上时,钢筋与再生混凝土间的黏结滑移性能退化明显;与普通混凝土试件相比,中高强再生粗骨料螺纹钢筋混凝土试件相对混凝土强度的黏结效率系数明显提高。
The key problem in the stress analysis of recycled concrete members is the bond-slip constitutive relationship between reinforced concrete and recycled concrete. The experimental study on the bond slippage of 49 reinforced concrete specimens with recycled concrete specimens was carried out. The specimen size is 150 mm × 150 mm × 450 mm, the diameter of the steel bars is 10, 14 and 20 mm respectively. The shape of the steel bars is divided into that of the screw steel bars. The length of the light steel bar and the steel bars is 5d, 10d and 20d, Aggregate replacement rates were 33%, 66%, 100%, respectively. The replacement rates of recycled fine aggregate were 50% and 100% respectively. The designed strength of concrete was divided into medium and high strength. The experimental results show that the replacement rate of coarse and fine aggregate, the strength of concrete, the shape of steel bar and the length of reinforcing steel bar are the key factors affecting the bond-slip performance of the specimen. When the replacement ratio of regenerated fine aggregate is above 50%, the bond between reinforcing bar and recycled concrete Compared with the ordinary concrete specimens, the coefficient of cohesion efficiency of the reinforced concrete specimens with medium and high strength recycled coarse aggregate concrete relative to the strength of concrete is obviously improved.