Research Of Cracks Control For High Performance Concrete In Continuous Rigid Frame Bridge At Mountain

The crack of the bridge structure is the important factor that influences its strength and durable, application of High Performance Concrete in long-span bridge make the early age cracking problem is becoming more and more common. Early concrete cracking, is an original composition by its own material, mixing ratio, temperature and humidity affect the global issues. Cement hydration process water consumption inside the concrete, lead to shrinkage deformation, hydration volume expansion caused by heat deformation, meanwhile, the evaporation of surface water has led to concrete drying shrinkage deformation, the deformation will produce internal stress, if the tensile strength of concrete can not resist internal stresses, which produce shrinkage cracks. Therefore, the analysis of concrete mechanism of contraction caused by temperature and humidity changes, and take scientific and effective technical measures to control early shrinkage cracks is meaningful, so, this article has done the following work:Firstly, elaborate the formation mechanism of early concrete shrinkage cracks, the influence factors of crack on the volume deformation is analyzed, For large volume of high performance concrete properties and hydration process of temperature and humidity change, lead to the cracking process are analyzed.Secondly, described the conventional early crack control measures for concrete, analysis the advantages and disadvantages of various methods, this paper proposes an adaptive early curing technology of long-span continuous rigid frame bridge.Finally, according to the construction of long-span continuous rigid frame bridge and the structure characteristics and climate environment, designed a set of cantilever construction early curing equipment, By the temperature and humidity sensors to detect temperature and humidity changes, Analyze the data collected through a set of control module, when reach a critical curing condition, the equipment is automatically controlled by the controller to curing of concrete, curing form is spray curing, it’s more scientific and reasonable than conventional sprinkler maintenance. By curing test, verify the feasibility. Then by analyzing the distribution of surface crack, surface permeability resistance, curing effection is analyzed and compared. Smart fog curing system maintenance effect is better than that of water conservation, can be applied in the maintenance construction.