Study On Durability Of Road Fiber Concrete Prepared By High Titanium Heavy Slag

There are many kinds of failure mode of cement concrete pavement,and the durability damage occupy most,which limits its wide application and service life in highway engineering.Due to the low design standard,poor construction quality,poor management and other reasons,many hydraulic concrete structures appear aging and disease and other durability problems prematurely.Therefore,it is an urgent problem to carry out the research on application of concrete durability,improving the service life of concrete and giving full play to great economic and social benefits.In order to study the properties of fiber reinforced concrete,the basic mechanical properties test,freeze-thaw test and sulfate dry-wet cycle corrosion test of fiber reinforced concrete specimens are carried out? And the microcosmic analysis of the specimens after freeze-thaw and sulfate dry-wet cycle is carried out in this paper.According to the experimental results,it is found that the compressive strength,bending strength and split tensile strength of high titanium heavy slag fiber reinforced concrete are better than those of ordinary concrete,and the basic mechanical properties of high titanium heavy slag fiber concrete are improved.In order to study its frost resistance,100 times,200 times and 300 times freeze-thaw cycle tests were carried out on 20 groups of concrete.Through the data of test and processing after freeze-thaw test,it is found that the mortar layer on the surface of fiber reinforced concrete specimens falls off in different degrees.And the more serious the number of freeze-thaw cycles is,the more serious the specimens.The group of six was not taken out the forming specimen after 200 freeze-thaw cycles.In addition to the surface shedding,the whole skeleton is intact,the freeze-thaw failure occurs from the surface to the inside,and the maximum mass loss rate is 3.58%.Among the specimens mixed with fiber,the relative dynamic elastic modulus decreased in very few groups,the quality and relative dynamic elastic modulus of concrete specimens without fiber decreased,which exhibits that fiber could improve the frost resistance of concrete specimens.And proper amount of fiber can prevent crack propagation after freeze-thaw cycle,which basalt fiber has better effect.After 30 times,60 times and 90 times of sulfate dry and wet cycles,the whole appearance of fiber reinforced concrete specimens is in good condition,and there is no spalling phenomenon.With the increase of the number of dry and wet cycles of sulfate,the more serious white spots appear on the surface of the specimens.The white spot is mainly ettringite that adsorbed on the surface of the specimen,which leads to the increase of thequality of most specimens.The lowest corrosion resistance coefficient of compressive strength is 88.1%,which can meet the requirements of the code.The results of scanning electron microscope(SEM)show that the surface of basalt fiber is smooth,and the fracture port of plastic steel fiber is uneven and there is distortion phenomenon.After freeze-thaw test,the hydration products are mainly lamellar and needle-like,and the hydration products are mainly needle-like and filled concrete after sulfate dry and wet cycle.