Experimental Research On Compressive Strength Of Concrete And Axially Loaded Concrete Short Column Atfer Freeze-thaw Cycle

The freeze-thaw cycle of concrete reduces strength and durability, concrete is an importantbearing material, and common used in cold region, inevitably will be affected by the naturalfreeze-thaw cycle of damage. At present many experimens study around concrete infreeze-thaw destruction, mainly research focus on the mechanism of freeze-thaw、concretematerials and admixture etc. A large number of experimental research at home and abroadmainly aim at the material composition of concrete to the influence of the frost resistance;Foreign scholars also analyze thoroughly in material level, but the freeze-thaw cycles ofstrength didn’t get system study. However, in its practical application, it is the most importantthat concrete cube concrete compressive strength as mechanics index, because the strength ofthe loss directly is related to the use of performance and security buildings. Though both athome and abroad have some relevant after the freeze-thaw cycle mechanical properties testresearch, or in some ways not systematic, for example the lack of the decrease of stressresistance is not systematic after freezing and thawing test of concrete, or the experimentalresearch is full of water in the state natural freeze-thaw cycle, there are big differences betweenthe actual engineering in freeze-thaw cycles, seeking the common concrete after freeze-thawcycles mechanical performance characteristics is close to the actual engineering, still need to doa lot of the experimental research. Find out all factors on concrete bearing capacity of decaylaws research is necessary. So between concrete freeze-thaw test enginery and true under theenvironment of natural freeze-thaw cycle test research are more practical meaning, specificallyaimed at different ages,temperature,time,different water cement ratio,maintenance condition,theinfluence of different design strength research, then can prevent concrete in actual project bythe freeze-thaw cycle of after cold harm, the system provides a theory basis and realistic basis.This paper mainly studies the content as follows:(1) In order to master the frost concrete structure of the actual project, to seven concretebuildings field investigation and testing work. Combined with personal practice and collect dataresearch, to build different ages,different used and different layer of concrete after freeze-thawcycles structure field investigation and measurement. This study is the quantity and quality ofthe investigation guarantee effectively. The study of field investigation and analysis the resultsshow that the concrete buildings cold harm are serious in northeast area, need to more researchthe actual engineering concrete freeze-thaw cycle; The age of concrete directly influences thestrength after the freeze-thaw cycle; The main factors of concrete structure are temperatureinfluence, cement varieties and materials and construction factors.(2) In order to study the influence factors of concrete compressive strength after thefreeze-thaw cycle, through the cube of freeze-thaw cycle test the compression resistance, contrast between concrete freeze-thaw test enginery and true under the environment of naturalfreeze-thaw cycle test research test, from the six factors of the age, cold temperature, time,water cement ratio,maintenance environment, design strength, analysis the change rule of thevarious factors concrete by20times after natural freeze-thaw cycle, the various factors ofconcrete after the freeze-thaw cycle influence the quality loss and the compressive strength, thevarious factors of concrete after the freeze-thaw cycle influence the change rule of thecompressive strength, concrast analysis the two states of concrete freeze-thaw test enginery andtrue under the environment of natural freeze-thaw cycle test research test.(3) In order to research the influence of the different factors of the reinforced concreteshort columns axial compression after freeze-thaw cycle, through the short column under axialbearing capacity test, from the four factors of the age, cycle time of freeze-thaw, curingenvironment, design strength, analysis the change rule of the various factors concrete afternatural freeze-thaw cycle, the various factors of concrete after the freeze-thaw cycle influencethe compressive strength, as well as the influence of concrete and steel load-strain, and analysisthe change rule of various factors load-strain curve. The various factors of reinforced concreteafter the freeze-thaw cycle influence the change rule of the compressive strength attenuation.The results show that the earlier age,the more times freeze-thaw cycle,the higher designstrength make concrete load-strain curve tended gradually flat, reduce peak load, increase peakstrain. Wet environment maintenance of the reinforced concrete short columns, lose less peakload, reduce peak strain, it is helpful to reduce the concrete strength loss after freeze-thawcycle.