Bond behavior between recycled aggregate concrete and deformed bars under uniaxial lateral pressure

Experimental and theoretical study of bond stress distribution between recycled concrete and deformed steel bar after freeze–thaw damage

“…where τ i ð Þ in Equation ( 14) is determined by Equation ( 8); γ c is the strain inhomogeneity coefficient of concrete, that is, the ratio of the concrete strain at the steel rebarconcrete bond interface to the average concrete strain in the cross-section, which is set to 2; and the other symbols are the same as in Equations (8)(9)(10)(11)(12)(13).…”

“…Recycled concrete, as a green construction material, has been greatly favored worldwide, and the bond behavior between recycled concrete and steel bar has become a focus of research. [11][12][13][14] In view of the possible adverse effects of the characteristics of recycled concrete (e.g., multiple interfaces, multiple cracks, and high porosity) on its durability, especially frost resistance, a number of researchers in China have studied the bond behavior of recycled concrete after freeze-thaw damage. [15][16][17] Their results show that after the same freeze-thaw cycle, the bond strength loss rate of recycled concrete specimens is higher than that of ordinary concrete specimens with the same water-cement ratio.…”

Experimental and Numerical Studies on Bond Quality of Fully Grouted Rockbolt under Confining Pressure and Pull-Out Load

“…e stress of a rockbolt acting on a deep rock mass changes to 10-15 MPa during its lifetime [31,32]. erefore, in numerical simulations, the con ning pressures of 0, 2, 5, 10, and 15 MPa are considered, which are used to analyze the in uence of con ning pressure on the ultrasonic guided wave propagation law and determine the bond quality of rockbolts under con ning pressure.…”

“…However, as the con ning pressure increases, the e ect of con ning pressure restricts the volume change of the microcracks and cracks in the concrete and cement mortar, and the restricting e ect increases with the con ning pressure. With increasing con ning pressure, the rockbolt and cement mortar are more closely bonded, the bonding ductility is strengthened, the radial force of the rockbolt is increased [31], and the bond quality of the rockbolt is improved. During the propagation of ultrasonic guided waves in the rockbolt, the radial vibration of the ultrasonic guided wave is restricted by the con ning pressure, which causes the wave packet to oscillate but does not reduce the propagation velocity of the guided wave, which is consistent with the experimental phenomenon.…”