Mesoscopic thermal field reconstruction and parametrical studies of heterogeneous rock-filled concrete at early age

Rock-filled concrete (RFC) is a highly heterogeneous material composed of rock blocks and self-compacting concrete (SCC). There is still limited literature regarding the non-uniform thermal behavior of early-age RFC, making it difficult to predict equivalent homogeneous parameters. In this study, a novel mesoscopic FEM model was developed to simulate the full-scale heterogeneous RFC, both considering the pre-placement of stochastic rocks and layered filling process of SCC into rock voids. Based on on-site experiments of an integrally-poured RFC arch dam, the mesoscopic simulation results were validated and showed good accordance with the monitoring data. The results show that: (1) Spatial heterogeneity in RFC is most pronounced within the first 4 h after SCC pouring, and the RFC temperature typically reaches its peak within about 3 days. (2) The maximum temperature rise observed for SCC is only around 6 similar to 7 degrees C, whereas the presence of the rockfill skeleton aids in the absorption of hydration heat, leading to a maximum temperature rise of 12.9 degrees C. (3) With a 5 % increase in the rock-fill ratio, the overall temperature level of the RFC model decreased by approximately 1 degrees C. (4) Increasing the adiabatic temperature rise of SCC by 10 degrees C, will lead to an approximate 3 degrees C rise in the highest temperature observed in RFC. These findings offer valuable insights for effective thermal control strategies in practical engineering applications.