Research Of Basalt Fiber Reinforced Concrcte Frost Resistance Experiment

In cold region, human sprinkle snowmelt agent on the road to reduce the effect of thefreezing point and keep the roads and airport runway in the ice and snow smooth. Butmelting ice, it brought freeze-thaw damage and corrosion of adverse effects to the road atthe same time, such as the appearance of denudation and cracks on the surface of road, thebearing capacity falling and premature failure, which had a great influence on the workinglife and safe use of concrete structure. Basalt fiber is a new type fiber material ofenvironmental green protection. Due to the high toughness, corrosion resistance,temperature resistance and crack resistance of itself and the reason cost performance isbetter than that of other fibers, basalt fiber can be taken as a reinforced material of concreteroad and improve the service life of concrete pavement. Meanwhile, with the progress ofscience and technology, basalt fiber reinforced concrete has been further application andpopularization. Therefore, research on frost resistance of basalt fiber reinforced concretehas very important practical significance.In the experiment, the volume fraction of basalt fiber and number of freeze-thawcircumstance are taken as variable parameter. The experiment respectively conducted fastfreeze-thaw test of basalt fiber reinforced concrete in the water,3.5%NaCl solution andaircraft deicing fluid. The concrete was studied the mass loss, dynamic elastic modulus,compressive strength, flexural strength of change rule and the final damage phenomenonunder different freeze-thaw cycle time and volume fraction of basalt fiber. By usingadvanced microscopic technology of Scanning Electron Microscope (SEM), microstructurechange and internal product structure of concrete are observed before and after freeze-thaw cycles. Basalt fiber content and circumstance which had an effect on the frostresistance and failure mechanism of concrete were analyzed.The results of macroscopic analysis show that in three kinds of freeze-thawcircumstance,3.5%NaCl solution which have an effect on the freeze-thaw damage ofconcrete is the most serious and the lightest is aircraft deicing fluid; Basalt fiber is added toimprove crack resistance of the concrete. with the increase of volume fraction of basaltfiber, the quality, weight, relative dynamic elastic modulus, compressive and flexural strength of the concrete after freeze-thaw cycle decline significantly slow. As a result, thefrost resistance of concrete is also improved.SEM analysis of the micro structure shows that the loose degree of cement pastegradually increase, the networking structure of cement hydrates of C-S-H gel destroy andthe numbers of holes, cracks and hydration products of ettringite crystal (AFt) increasewith the increasing numbers of freeze-thaw cycle. The result shows that damage degree ofconcrete structure increase. After mixed with basalt fiber, it weaks damage degree offreeze-thaw and is beneficial to the improvement of the performance of the concreteantifreeze through easing the stress by freeze-thaw cycle, delaying the emergence of microcracks, reducing the number of the micro cracks, holes and crystal of hydration products.