Study On Corrosion Resistance Of High Titanium Heavy Slag Concrete Under Multi-factor Coupling

Since the 1970 s,high titanium heavy slag has been widely used as concrete aggregate in practical engineering construction,which not only conforms to the concept of green building and green building materials development in China,but also can greatly improve the comprehensive utilization rate of natural resources and reduce the pollution of industrial production wastes to the natural environment.The corrosion resistance of high titanium heavy slag concrete has been highly concerned by scholars and experts from all circles.In order to meet the use requirements in special and complex environments,it is often necessary to study the actual feedback under the action of multiple factors,so as to better fit the actual working environment of the building.Firstly,according to the size of the water-cement ratio and different dosage of fly ash,preparation of C30 high titanium heavy slag concrete,adopting orthogonal experimental design,study the related basic mechanical properties,and selection according to actual engineering conditions more widespread corrosion damage factor: destruction of freeze-thaw cycle,chlorine salt corrosion and sulfate corrosion,analysis respectively under the effect of double factor and multiple factors coupling high titanium heavy slag concrete corrosion resistance degradation rule.The influence of water-binder ratio of 0.50,0.55,0.60 and fly ash content of 0,10%,20% on the mechanical strength index of high titanium heavy slag concrete is studied,and the cube compressive strength,bending strength and splitting tensile strength of high titanium heavy slag concrete are tested respectively.Through the comparative analysis of three different strengths,the factors affecting the strength are summarized: the water-binder ratio is always relatively significant,but considering the actual performance and economic cost of high titanium heavy slag concrete,the comprehensive conclusion is that the water-binder ratio of C30 high titanium heavy slag concrete should be 0.50,and the fly ash content should be10%.The compressive strength,flexural strength and splitting tensile strength of this group of high titanium heavy slag concrete are 45.9 MPa,4.7 MPa and 3.28 MPa,which not only meet the requirements of strength performance but also have good workability.Under the multi-factor coupling action test,the level factors of salt solution concentration of 2%,5% and 10% were added.Through the mass loss rate and relative dynamic elastic modulus,it can be seen that the chloride salt freeze-thaw coupling has the most serious corrosion damage on the high titanium heavy slag concrete,and the number of salt freezing cycles only reaches 100 times.Secondly,chloride sulfate freeze-thaw three factors coupling,salt freezing cycles reached 150 times;The corrosion damage is the slowest when the sulfate freeze-thaw double factor is coupled,and the damage standard is not reached when the salt freezing times are 200 times.In the three groups of salt freezing tests,salt solution concentration has the most significant effect on the corrosion degree of high titanium heavy slag concrete,but the corrosion failure rate of freeze-thaw specimens with higher concentration of salt solution is the slowest.Under the same conditions,the greater the water-binder ratio,the greater the fly ash content,the worse the salt freeze-thaw resistance of high titanium heavy slag concrete.Through SEM and XRD test,it is concluded that brine crystallization expansion damage is the main factor and corrosion product expansion damage is the secondary factor in the fracture mechanism.