Freezing Conditions And Sir-Entraining Agent Study On Frost Resistance Of Concrete

Along with our country,to the attention of the hydropower resources development and utilization of investment increase,built a number of important water resources and hydropower hub,the project of national development,economic growth play a major role in life.By its is the hydraulic structures,hydraulic concrete in water or dry and wet state for a long time,inside the concrete,there are plenty of frozen water,under the freezing temperature,enormous pressure,when more than concrete tensile strength are produced by local cracks.Under the effect of repeated freeze-thaw cycle,the damage to repeatedly,cracks expanding,mutual penetration,makes concrete material degradation,eventually lead to destruction.Many concrete buildings for antifreeze performance is poor,came in a short period of time after the completion of the different degree of freeze-thaw damage,thus affecting the structure of the use of performance,pose a threat to the safety of the project,and cause huge economic loss,therefore engineering of concrete antifreeze performance become the durability of the concrete.In a cold environment,due to the conditions of each are not identical,formation damage are different.Paper from the three aspects of concrete frost resistance are studied.(1)respectively for freezing and thawing,saturated freezing and thawing frozen.dry and wet conditions,after 125 times of freeze-thaw cycle,every 25 times after the freeze-thaw cycle,comparing the strength of concrete,quality research under the condition of hydraulic concrete freeze-thaw cycle performance,it is concluded that in different cold condition after freezing and thawing cycles of freeze-thaw damage of concrete freezing and thawing in the dry and wet conditions is most serious,followed by saturated freezing and thawing.(2)by adding different quantity of air-entraining agent to adjust the air content of concrete conditions,the different air content of concrete in the freeze-thaw cycles under the condition of concrete strength,the quality loss,it is concluded that under the condition of dry wet freeze-thaw cycle best air content of concrete,on the premise of guarantee the cement strength reducing resource consumption and production cost,enhance the durability of concrete.The experiment results is 0.022%when the air-entraining agent air content of concrete is 3.9%antifreeze optimal performance.(3)three different air-entraining agent were used respectively to analyze the concrete the performance impact,it is concluded that rosin hot polymer air-entraining effect is best,when the air content of concrete after the loss is small,the concrete slump loss is small,28 d compressive strength of concrete strength loss and the freeze-thaw effect is small.The experimental simulation freeze-thaw cycle different cold conditions in real environments,different dosage of air-entraining agent and air-entraining agent comparing the strength of concrete under respective conditions and the change of mass loss,analysis the influence of various performance experiment of various factors on concrete,finishing the test data as a feasible and reliable in practical engineering conditions to test and improve the durability of concrete,ensure the engineering quality.