There are lots of mass concrete construction in modern building like the foundation of high building and large scale equipment, dams and so on. With no specific definition, mass concrete is extremely massive and is no less than 1m in entity minimal size, with low surface coefficient and low hydration heat of cement causing increasing temperature of concrete. Great temperature difference would lead to temperature-related cracking of concrete, impacting the construction safety, so it must be analyzed at the root cause to ensure construction quality.
ACI states: Mass concrete is any volume of concrete with dimensions large enough to require that measures be taken to cope with the generation of heat from hydration of
the cement and attendant volume change to minimize cracking.
It has following characteristics: Being thick structure, costing large amount of concrete, with complicated engineering conditions (usually the reinforced concrete structure being poured underground), it requires higher construction technology, for the heat of hydration of cement is quite high (estimated over 25 degree ) and may cause temperature cracking. Besides regulations on the minimum section and the internal and external temperature, mass concrete also has regulation on plane size, because the bigger plane size would cause more temperature stress, and if the temperature is controlled improperly, the temperature stress would surpass the tensile strength peak of the concrete and easily cause cracking.