Cracks in Mass Concrete at Early Ages in Haditha Dam

Mass concrete in the central part of the Haditha dam is placed in unfavourable arid and hot climate with great temperature differences. An additional problem was raised by the characteristics of the available aggregate sources : small maximum size and gap grading. The appearance of maximum temperature in mass concrete, formation of thermal gradient, and crack appearance have been analysed.Special attention was paid to the formation of thermal gradient near block surface in sudden temperature changes. The results of numerical calculations have been compared to measurements on the site. Each concrete block was examined and possible cracks were noted before pouring subsequent blocks. Crack frequency was correlated to characteristics parametres. The results prove that there is no need to limit block height in order to avoid cracking risk or to exceed maximum temperatures in given climatic condition with the concrete mix design considered.