RC类活性粉末混凝土钢筋锚固性能试验研究

Experimental study on anchorage properties of RC reactive powder concrete and steel bars

为了研究RC类活性粉末混凝土与钢筋的粘结锚固性能,分别以RC类活性粉末混凝土抗压强度、钢纤维体积掺量、钢筋直径和钢筋的粘结长度为参数,设计制作了22组试件。对试件采用中心拔出试验,获得各试件的试验数据。对试验数据的分析结果表明:随着RC类活性粉末混凝土抗压强度的增大,混凝土与钢筋间极限粘结强度呈线性增长;钢纤维的掺入量能有效延缓裂缝的发展;钢筋与混凝土间极限粘结强度随钢筋直径的增大而减小,且钢筋与RC类活性粉末混凝土的粘结长度越长,粘结应力分布越不均匀。基于试验数据提出了RC类活性粉末混凝土与钢筋极限粘结强度计算公式,进而采用中心点法并参考现有混凝土设计规范中关于钢筋锚固长度的计算方法,建立了RC类活性粉末混凝土与钢筋粘结锚固长度的计算公式。

In order to study the bonding and anchoring properties of RC reactive powder concrete and steel bars, 22 sets of test pieces are designed and fabricated based on the compressive strength of RC reactive powder concrete, the volume of steel fiber, the diameter of steel bars and the bond length of steel bars. The center pull-out test is applied to the test piece to obtain test data of each test piece. The analysis of the test data shows that: with the increase of compressive strength of RC reactive powder concrete, the ultimate bond strength between concrete and steel bar increases linearly;the amount of steel fiber blended can effectively delay the development of cracks;the ultimate bond strength between steel and concrete decreases with the increase of steel bar diameter, and the longer the bond length between steel bar and RC active powder concrete, the more uneven the bond stress distribution. Based on the experimental data, the formula for calculating the ultimate bond strength of RC reactive powder concrete and steel bars is proposed, furthermore, using the central point method and referring to the calculation method of the anchor length of the steel in the existing concrete design specification, the calculation formula of the bond length of the RC active powder concrete and the steel bar is established.