Research on the Mixing Mechanism of Fiber Reinforced Concrete Prepared from Blast Furnace Slag Fibers

Blast furnace slag fiber is a new type of cotton like inorganic fiber material, which is mainly prepared from blast furnace slag through remelting, tempering, and centrifugal injection. Blast furnace slag fibers have the advantages of light weight and good high-temperature resistance (mainly reported in practical reports), and are widely used in many industries. However, there is little research on its relevance as a reinforcing material for cement concrete. The article combines the performance and requirements of other fiber reinforced concrete to study the alkali resistance of blast furnace slag fibers and their impact on the properties of cement mortar and concrete materials. The research content and conclusions are as follows:

1) Explored the alkali resistance performance of blast furnace slag fibers. Research has shown that the corrosion degree of fibers increases with the increase of alkali concentration, soaking time, and temperature, and their alkali resistance performance is poor. 2) The effect of blast furnace slag fibers on the performance of cement mortar was studied. Adding blast furnace slag fibers can increase the strength of mortar specimens, and the actual effect is mainly on the drying shrinkage performance of the material. When the fiber content is 0.60%, it is more suitable. After 28 days of curing, the flexural strength of the specimen increased by 12.5% and the compressive strength increased by 7.66%; When the fiber mass fraction is between 0.5% and 1%, the actual effect of fibers on the drying shrinkage performance of cement mortar is mainly significant.

3) The influence of fiber acidity coefficient and fiber type on the mechanical properties of cement mortar was studied at the same dosage. The experimental results show that the larger the acidity coefficient, the stronger the interaction forces between the network structures inside the fibers, and the stronger the alkali resistance of the fibers. The actual effect on the performance of cement-based composite materials is mainly better. The effect of blast furnace slag fibers with an acidity coefficient of 1.4 on cement mortar is better than fibers with Mk=1.1, 1.2, and 1.3. In addition, blast furnace slag fibers have a better effect on the early growth of mortar than basalt fibers and polypropylene fibers. In the later stage, due to the poor alkali resistance of blast furnace slag fibers, their increasing effect is weaker than the other two types of fibers. 4) The changes in the mechanical properties of concrete matrix materials were studied when 0.25% to 2% blast furnace slag fibers were added to the concrete matrix. The results showed that after adding fiber with a mass fraction of 2% and curing for 28 days, the compressive strength of the specimens increased by 7.27%, the flexural strength increased by 17.42%, and the actual effect of splitting tensile strength was mainly not significant