In this study, ring restraint heating tests were conducted at 3, 8, 22, and 42 days of age to evaluate the possibility of fire spalling at an early age for heat-resistant cross-sectional repair materials (HRM) that can be used up to 300 ℃. The same tests were also conducted for the case with 0.2 vol% jute fiber for fire spalling control. The required strength can be obtained in about one month after casting. Therefore, the early age was defined as within one month after casting. The results indicated that without jute fibers, the ring specimen spalled at an early age. The earlier the age of the specimen, the more significant the degree of spalling. However, the inclusion of jute fibers prevented spalling at all ages. In addition, the tensile strain caused by the confining restraint stress tended to increase with the age of the specimens. 0.2 vol% jute fibers increased the tensile strain owing to the cross-linking effect of the fibers. The calculation of the tensile strain showed the possibility of assessing the risk of spalling.