Crack Control And Construction Technology Of Mass Concrete

Releasing steam heat from the mass concrete structures while solidifying leads toproduce the temperature change and contraction. They cause crack in the massconcrete structures and the cracks destroy the completeness and durability of concrete .Thus, crack control must be considered while a mass concrete structure is constructedAccording to the characteristic of winter construction , crack control measuresand construction technology of mass concrete were systemically researched. Firstly,through studying mechanism of the concrete being frozen and crack control ofconcrete under low-temperature ,the forming of crack under low-temperature and thecontrol measures were discussed;Then , mechanism of mass concrete crack and thecontrol measures were explored;Finally ,in responding to three engineering instances,this paper presented the concrete crack control measures under low temperature ,theresearch of using heat storing method (without addition of anti-freeze agent and earlystrength agent) in winter construction for mass concrete , heat engineering calculationof the heat storing method in winter construction . There are mainly three problemsshould be solved in concrete winter construction : first, how to determine the shortestage of concrete curing;second, how to prevent the concrete being frozen at earlystage;third, how to insure the later strength and durability of concrete meeting thecode requirements. During reality construction, air temperature, state of structureconstructed (construction quantities, structure volume and exposed degree), urgencyof project time limit , type of concrete and price, the performance and price ofconcrete early strength agent, water reducing agent and anti-freeze agent, and the heatinsulating material all should be taken into consideration and then decide the properconstruction procedure. There might be several different schemes for the same project.The best construction quality should be got with the shortest construction time andlowest construction cost in an appropriate construction scheme, while time, cost andquality reach the optimality.