Temperature And Cracking Control Of Mass Concrete

Mass concrete is easy to crack if constructed improperly, because of its huge volume and complicated construction condition. And the cracking will either affect the durability of the concrete structure, or even influence the mechanics performance of the concrete. So avoiding the mass concrete from cracking has drawn the attention of the engineering field of the whole world. As the variety of mass concrete application and its complexity, the cracking of mass concrete is occurring at large. These problems request us to do more researches on cracking mechanism, cracking development, assessment criteria and cracking control methods.Based on the former fruits of temperature control and cracking prevention, the temperature stress, cracking causes and cracking control measures are studied from the macro-aspects such as: raw materials, mix ratio, additives and construction technology , and also from the micro-structure of concrete. The effect of the combination of temperature stress and the multi-stress caused by the dry shrinkage, self-shrinkage, temperature shrinkage and plastic shrinkage is considered, and the basic cracking control measures are concluded. And new temperature and cracking control method is created , which applies the carbon fiber reinforced concrete techniques into the temperature and cracking self-monitoring.On the early cracking research, the indirect assessment methods such as: hydration test, isolation temperature rise test and shrinkage test, and direct assessment methods such as: ring restraint test and single axis restraint test are studied to contrast the different cracking performances of different concrete mixtures in this paper. The causes affect the early cracking of concrete are analyzed here and the cracking assessment criteria based on the temperature-stress test is concluded: temperature of the second zero stress<40℃, stress storage>35% and cracking temperature <14℃...