The Quality Detection And Control Of Raft Mass Concrete Of Rui’an World Building Phase ⅱ

In recent years, with the rapid development of economy in our country, theengineering construction scale increases, at the same time, the mass concrete has beenwidely used in bridge、subway and high-building. Because of the mass concretegenerally has a large size which makes the cement hydration heat difficult to send outand a huge rise of internal temperature of concrete. The high internal temperature willcause a larger expansion; In the late cooling stage, with the internal temperaturegradually returning to ambient temperature, there will be a bigger contraction. Thestructure and performance characteristics of the mass concrete will cause through crack,especially in the cooling stage. Crack’s appearing greatly increase the difficulty ofengineering maintenance and maintenance costs; On the other hand, crack alsoaccelerates reinforcement corrosion which will seriously reduce the integrity anddurability of the mass concrete, endangering the safe use of structure. To some extent,the quality control of mass concrete is controlling the temperature crack of concrete.This topic regarding the quality detection and control of the raft board massconcrete of the Chongqing Rui’an World building phase ii as the background (19000m~3,now the largest amount in Chongqing), guided by the temperature stress theory of massconcrete, making crack comprehensive control as a means, during the raft boardconstruction, controls the quality of raw materials of concrete, and improves thestability of the concrete performance; Optimizing the mix proportion of the concrete,according to the hydration heat test of binding material and physical and mechanical test,chooses a optimal mix proportion with low hydration heat, good workability, satisfiedstrength; By using the theory of crack control and calculating the anti-crack safetycoefficient, examines whether the raft board mass concrete satisfies the requirement ofcrack resistance; Construction organization and concrete company make discussions formany times and demonstrate the rationality of construction plan repeatedly, as far aspossible to eliminate all hidden trouble which will cause quality problems; Set upreasonable thermal insulation layer and monitor the mass concrete temperature afterpouring, controlling the concrete inside and outside temperature difference, concretesurface and the environment temperature difference, the highest temperature inside theconcrete in a reasonable range. Through the comprehensive application of the qualitydetection and control measures, it has proved that the temperature crack control of raft board mass concrete is feasible. At the same time, the stress data obtained from thestress monitoring system setting up in the internal of mass concrete, provide the basisfor analysis of temperature stress, and lay a certain foundation for the further research inthe future.