型钢与地聚合物混凝土粘结滑移性能研究

为了研究型钢与地聚合物混凝土之间的粘结滑移规律,对9个型钢地聚合物混凝土柱试件进行推出试验,研究地聚合物混凝土抗压强度、型钢的保护层厚度、型钢的锚固长度以及配箍率四个参数对型钢地聚合物混凝土试件荷载-滑移曲线、破坏形态以及粘结滑移性能的影响。结果表明:试件的荷载-滑移曲线具有相同的发展趋势,可将其划分为无滑移段、荷载上升段、荷载下降段和水平残余段四个阶段;试件的破坏模式为混凝土劈裂破坏,劈裂裂缝从加载端型钢翼缘产生,并向自由端发展;随着地聚合物混凝土抗压强度、型钢的保护层厚度和配箍率的提高,试件的特征粘结强度呈上升趋势;与普通水泥型钢混凝土不同,型钢的锚固长度增大也会使试件的特征粘结强度提高。根据试验结果,建立了特征粘结强度的计算公式,提出了型钢地聚合物混凝土的粘结-滑移本构模型,采用该模型计算得到的型钢地聚合物混凝土粘结-滑移曲线与试验曲线吻合度较高。

Bond-Slip Behavior Between Steel Section and Geopolymer Concrete

Nine push-out test specimens were made and experimented to study the bond-slip behavior between steel section and geopolymer concrete. The influences of four factors such as compressive strength of geopolymer concrete, concrete cover thickness, embedded length of steel section and stirrup ratio on the load-slip curves, failure modes and bond-slip properties of the steel reinforced geopolymer concrete specimens were studied. The results show that the load-slip curves of different specimens have the same development tendency and can be divided into four stages: no slipping stage, load increasing stage, load declining stage and horizontal residual stage. The failure modes of specimens are bond splitting failure, cracks originate from the flange of the steel section at loading end and develop to the free end. As the compressive strength of geopolymer concrete, concrete cover thickness and stirrup ratio increase, the values of characteristic bond strength of specimens present a tendency towards growth. Unlike the steel reinforced concrete with ordinary cement, the values of characteristic bond strength of the specimens increase with the increase of embedded length of steel section. According to the test results, the calculation formulas of the characteristic bond strength are established, and the constitutive model of the steel reinforced geopolymer concrete is proposed. The bond-slip curves calculated by the model agree well with the experimental curves of steel reinforced geopolymer concrete specimens.