锈蚀植筋下新老混凝土黏结面压剪试验研究

为研究锈蚀植筋下新老混凝土的黏结性能,采用某工程锈蚀钢筋作为植筋,制备了不同植筋率(0、0.223％、0.446％、0.502％、0.893％、1.004％、1.396％、1.786％和2.792％)的新老混凝土试件.在RYL-600微机控制岩石伺服剪切流变仪上进行了不同初始静压力(0、1、2、3和4 MPa)下混凝土试件的剪切试验.对试件的剪应力-位移曲线进行了归纳总结,得到了锈蚀植筋下新老混凝土试件在外力作用下产生变形乃至破坏的演化规律;分析了锈蚀植筋下新老混凝土黏结面的抗剪强度,得到了抗剪强度随植筋率及初始静压力变化的规律.同时根据试件试验破坏结果,着重分析了不同植筋率和不同初始静压力对其破坏模式的影响.试验结论为新老混凝土力学性能的研究提供了理论依据.

Experimental research on load-shear performance of interface between new and old concrete with corroded planting bar

Thus far, a lot of concrete structures have been aging owing to the rapid development of highways, railways, and the construction industry in China. Concrete structure diseases, such as concrete surface cracks and erosion, require serious consideration due to the effect of long-term use and environmental impact. Some man-made factors have exacerbated these problems, such as insuffi-cient operating level and corners, among others. This has obscured safety risks associated with these concrete structures. However, not all of these structures could not be decommissioned to reduce the negative social and economic impact and to ensure the safety of build-ings;therefore, a reasonable approach was to repair and reinforce the old concrete structures. Additionally, in the process of mainte-nance and reinforcement, planting bars between the new and old concrete must be considered, and especially the corroded planting bar from an aged project that has been terminated. Many studies for the bonding performance of new and old concrete have been conducted by the experts and scholars at home and abroad;thereby, some results have been achieved. Only a few scholars have investigated the bonding performance between new and old concrete with planting bars and especially corroded planting bars from old reconstruction pro-jects that have been terminated. Therefore, investigating the shear performance of new and old concrete with corroded planting bars was of utmost importance. To study the mechanical properties of the interface between new and old concrete with corroded planting bars, the new and old concrete specimens with different planting bar ratios (0％, 0. 223％, 0. 446％, 0. 502％, 0. 893％, 1. 004％, 1. 396％, 1. 786％, and 2. 792％) were prepared based on the corroded planting bars. These corroded planting bars came from the tunnel lining structure of a project that had been terminated for over five years. Shear tests were conducted for new and old concrete under different initial static pressures (0-4 MPa) in an RYL-600 microcomputer control servo rock shear rheometer. The evolution law of the deforma-tion and destruction of new and old concrete specimens under the action of external forces was obtained through summarizing the shear stresses and displacement curves of the specimens. The law of shear strength along with the variation of the steel planting ratio, as well as the initial pressure, were acquired by analyzing the shear strength of the new and old concrete interface with corroded planting bars. Moreover, the influence of different planting bar ratios and the initial pressure on the failure mode of concrete specimens was analyzed emphatically based on specimen failure results. The test results provided the theoretical basis for investigating the mechanical perform-ance of new and old concrete.