Study On The Numerical Simulation Of Freeze-thaw Cycles For Concrete

Concrete is applied widely in architecture structure. Since concrete structures areexposed to the outside over a long period of time, its durability has become a majorproblem in the field of civil engineering. Under the interaction of material inner factors,the natural environment and the working environment, the performance of concretestructure degenerated gradually and then concrete durability damage appeared.Accounting for the fact that the weather of China is very cold in winter, the mostconcrete structures suffer in the freeze-thaw damage in the varied low temperature.Long-term effect of freeze-thaw cycles could cause concrete surface spalling seriously,then the interior steels were exposed to the outside. Therefore, gradual corrosion damageoccurred for the reinforced steels, and the bearing performance of concrete structuresdeclined seriously，which was a great threat to human lives and properties. Therefore, theconcrete durability damage problem caused by the freeze-thaw cycles can not be ignored.In the present paper, the mass loss rate and strength loss rate were used as two importantindexes for the judgment of concrete freeze-thaw cycles damage. Based on the testing,numerical simulation on freeze-thaw test is analyzed through ABAQUS software of finiteelement analysis. The influence of different freeze-thaw cycles to various strength gradeconcrete are discussed, therefore the difference of concrete frost resistance in differentstrength grade are analyzed.This experimental study is combined with practical engineering project in Anhuibranch of Hebei Construction Group. The reduction in strength and the mass lossproblems were studied and numerically simulated after suffering freeze-thaw cycles.Standard concrete specimens（Φ100mm×50mm）were made, and the experimentmethods was shown as follows: firstly, numerical simulation for compression test wasapplied to obtain the stress-time curve; secondly, numerical simulation for temperaturefield was applied to obtain the temperature curve; thirdly, numerical simulation forthermal stress sequential coupling was applied to analyze the change regulation of stress,strain and strength loss according to the experimental results; fourthly, numericalsimulation for compression test after suffering freeze-thaw cycles were carried out toobtain the stress-time curve, so that concrete maximum pressure after sufferingfreeze-thaw cycles was estimated; at last, the simulated results were compared withexperimental results to testify the feasibility of numerical simulation because it turned out that the comparisons of the simulation results with experimental results on the wholewere true. It is a new convenient method to study the freeze-thaw damage of concreteand it can offered a beneficial reference to freeze-thaw damage problem in practicalengineering. The conclusion are made through experimental results as follows: the massloss rate and strength loss rate are reduced obviously with the increase of freeze-thawcycles times; the anti-frost property significantly improve with the increase of concretestrength. Therefore, this paper intends to provide a theoretical basis to facilitate futurestudies, which also makes it possible to study large-scale structural problems.