Research On The Destruction Mechanism To Preventing And Curing Technology In The Thin Shell Aqueduct Of Armored Concrete

The aqueduct is the important inputting water building of irrigated area, because of historical or other reasons, lead to the fact the top structure of the aqueduct is destroyed, such as concrete peeled off, some leaked seriously; Aqueduct underpart structure especially basic part erodes and destroys seriously because of high ore degrees of groundwater, all these have influenced the safe operation of the aqueduct seriously, Through analyzing and studying to the environment and destroys the characteristic of the Jing-dian irrigated area aqueduct, this text have confirmed the main factor causing the aqueduct to destroy, according to destruction mechanism, we have proposed preventing and repairing the measure. Main research contents and achievements have:(1)Through studying groundwater salt environment, and investigation of the destruction of the Jing-dian irrigated area aqueduct, have confirmed that carbonization, reinforcing steel bar corrosion are the main reason causing the upper structure of the aqueduct to destroy; And the main reason causing the underpart structure of the aqueduct to destroy is sulphur acid radical, chlorine ion, frozen and melted.(2)On the basis of consulting a large number of materials and summarizing forefathers' experiences, analyse in depth the mechanisms and influence factors of carbonization, sulphur acid radical and chlorine ion corroding, reinforcing steel bar corrosion, that caused the concrete structure destroys; Point out the chlorine ion has not turned into the new material when the erosion of the reinforcing steel bar, only play a role in accelerating the corrosion of reinforcing steel bar, but chlorine ion invade into the concrete, and react hydration of cement, having produced the new material, "Friedel salt " , Confirmed the mathematical model spreading of chlorine ion, has established the foundation for the surplus life preciction of the aqueduct.(3)We have got predicting mathematics models of the depth of carbonization according to Fick law, and have summarized domestic and international existing the practical predicted models of carbonization, compared the models of carbonization in the laboratory through the fast carbonization law, point out what carbonization model accord with project reality even more.(4) In order to study the performance of resisting sulphate and corrosion of basic concrete of aqueduct, we try one and carry on the experimental studying sulphate corrosion and freezing - melting destruction throug different mix proportion of concrete, point out that mixing fly ash and water-reducing agent can improve effectively the ability to resist sulphate corrosion and freezing - melting destruction, the resisting ability and compression strength is increasing when the the fly ash proportion increase, but the proportion of fly ash over 30%, the compression strength of concrete drops, at the same time,freezing - melting destruction standards go on the discussion, propose adopting 80% that the relative moving modulus drops to initial value as the destroying standard.(5)The characteristic destroyed to the Jing-dian aqueduct, has proposed preventing and repairing the measures.This thesis has realistic meaning of making the active service aqueduct lengthen service life, instruct the structure yet to be built to resist and corrode the theory value designed, at the same time references are offered when the water conservancy project building in the Northwest no matter which is newly built, rebuild, extending and regular maintenance.