Experimental Research On Mechanical Properties And Durability Of Hybrid Fibers Light-weight Aggregate Concrete By Fractal Theory

As civil engineering materials,concrete is one of the most widely used materials in national economic construction.It has a lot of merits,such as its rich resources,good economical effect and high flexibility,etc.However,there are also some disadvantages,which restrict the development of concrete,such as the heavy self-weight,poor tensile property and so on.In order to improve these shortcomings,people have been searching for a long time to find new materials,which can be added into concrete.A large number of studies have shown that to take natural pumice light-weight aggregate concrete as coarse aggregate of concrete,which is being blended with hybrid fiber can not only enhance the toughness of concrete,but also can improve its durability and dead weight.This paper will relate to the advantages of region resources of its natural pumice reserve in Inner Mongolia Autonomous Region.By using of natural pumice as light-weight aggregate to mixed the hybrid fiber reinforced concrete in the area of Jining,this paper pays its attention on the study of the relationship between the macroscopic and microscopic properties for hybrid fiber(polypropylene fiber and basalt fiber)mixed with light-weight aggregate of pumice concrete.In terms of macroscopic aspects,this article tries to test the impact of hybrid fiber reinforced light-weight aggregate concrete incorporating the effects of hybrid fiber through the concrete compressive strength.While for the durability aspect,the freeze-thaw cycle damage experiment has been chosen to analyze the mass loss rates and relative dynamic elastic modulus of the two parameters specifically.Meanwhile,the mechanism of fiber's performance and its enhancement to concrete macroscopically.From microcosmic point of view,the pore structure parameters of concrete are being observed and calculated from different scales in various ways.Meanwhile,the effects of different fractal dimensions on the model are being discussed and two methods are finally being chosen to calculate the fractal dimension for the two scales.Further discussion and research are carried out by the fractal dimension together with the previous experimental parameters and results.Finally,based on fractal dimension and freeze-thaw damage model,the freeze-thaw damage model of hybrid fiber reinforced light-weight aggregate concrete has being obtained.The results show that in hybrid fiber reinforced light-weight aggregate concrete,when the volume of basalt fiber and polypropylene fiber respectively within a reasonable range,the mechanical properties and frost resistance durability of hybrid fiber has been reinforced and lightweight aggregate concrete will be improved.The results showed that indicators are optimal when the basalt fiber volume fraction is 0.7kg/m3 and polypropylene fiber volume fraction is 0.6kg/m3.