This study focuses on the fracture behavior of recycled aggregate concrete (RAC) after exposure to elevated temperatures, thus, a total of 128 cubic specimens and 64 notched beams were cast to analysis the effects of recycled coarse aggregate (RA) substitutions (0%, 30%, 70% and 100%) and elevated temperatures (20 °C, 100 °C, 200 °C and 300 °C) on fracture parameters of RAC, such as peak load (P_max), critical crack mouth opening displacement (CMOD_c), critical crack tip opening displacement (CTOD_c), effective crack length (a_c), fracture energy (G_F), initiation fracture toughness ($K_{IC}^{ini})$, unstable fracture toughness$(K_{IC}^{un}$), the characteristic length (L_ch) and so on. The result showed that the values of P_max decreased as the increase of exposure temperature and the decrease rate grew slower as the increase of RA substitution. In contrast, the values of G_F increased with elevated temperature and the increased rate grew slow with the incremental of RA replacement. As the increase of RA substitution, the CMOD_c and CTOD_c of specimens slightly increased first and then decreased at ordinary temperature and elevated temperature. The $K_{IC}^{ini}$ and $K_{IC}^{un}$ of concrete with different RA substitution decreased with the elevated temperatures. In addition, the RA substitution had a positive impact on the $K_{IC}^{ini}$ of concrete after exposure to 200 °C and 300 °C. At each high temperature, the L_ch of RAC was smaller than that of natural aggregate concrete (NAC), indicating that the ductility of RAC was worse than that of NAC.

这项研究的重点是再生骨料（RAC）在暴露于高温后的断裂行为，因此，共浇铸了128个立方试样和64个带缺口的梁，以分析再生粗骨料（RA）替代的影响（0％， 30％，70％和100％）和高温（20°C，100°C，200°C和300°C）对RAC的断裂参数（例如峰值载荷（P _max），关键裂纹口张开位移（ CMOD _c），临界裂纹尖端张开位移（CTOD _c），有效裂纹长度（a _c），断裂能（G _F），初始断裂韧性（${ķ}_{\mathrm{一世}C}^{\mathrm{一世}ñ\mathrm{一世}}）$，断裂韧性不稳定$（{ķ}_{\mathrm{一世}C}^{üñ}$），特征长度（L _ch）等。结果表明，随着暴露温度的升高，P _max值降低，而随着RA取代度的增加，降低速率的增长速度变慢。相反，G _F的值随着温度的升高而增加，并且随着RA替代物的增加，其增加速率增长缓慢。随着RA替代量的增加，在常温和高温下，样品的CMOD _c和CTOD _c先略有升高，然后降低。的${ķ}_{\mathrm{一世}C}^{\mathrm{一世}ñ\mathrm{一世}}$ 和 ${ķ}_{\mathrm{一世}C}^{üñ}$随着温度升高，具有不同RA替代率的混凝土的比重降低。此外，RA替代品对${ķ}_{\mathrm{一世}C}^{\mathrm{一世}ñ\mathrm{一世}}$暴露于200°C和300°C后的混凝土。在每个高温下，RAC的L _ch均小于天然骨料混凝土（NAC）的L _ch，表明RAC的延展性较NAC差。