Similar to most of the other developing countries, Vietnam has national programs for industrial waste recycling including fuel, ash, and slag. In which, fly ash (FA) has been used commonly as a pozzolanic additive in the roller-compacted concrete (RCC) mixture for the dam construction of hydropower projects. This usage allows reducing the concrete cost, the hydration heat, and the thermal cracking during the construction process of the RCC. In this study, the optimal concrete mixture and the maximum temperature of the RCC dam were determined using the experiment planning method, Matlab, Maple 13, and Midas Civil. In addition, the mathematical model has been used to adequately describe the influence of the intensity concreting (IC) and the initial temperature of the concrete mixture (ITC) on the temperature regime of the RCC dam. The calculation of the temperature regime during the construction of the RCC dam of 45 m high and 1 m thick in Vietnamese climate conditions was performed with considering the IC and the ITC. As the results, the maximum temperature of the RCC dam was determined depending on the IC and the ITC. Calculation found that at IC = 0.6 m/day and ITC = 20°C, the maximum temperature in the central dam zone reached 36.38°C after 1800 hours from the beginning of construction. The results of the present study further support the safe and durable construction of the RCC dam in the future.