At present, adding proper amount of waste tire rubber powder to concrete can not only improve the frost resistance of concrete, but also solve the problem of pollution of some used tires. It is typical of recycling of waste rubber resources; fly ash is the main solid waste discharged from coal-fired power plants. It can also be used as a blend of concrete. So, can you add fly ash to concrete materials with tire rubber? What is the role of fly ash in rubber powder modified concrete?
The use of waste tire rubber powder in concrete can improve the frost resistance, crack resistance, impermeability, shock absorption, thermal insulation performance and calendering performance of concrete; fly ash is used as dye waste excluded from coal-fired power plants, part of The use of alternative cement in concrete can reduce costs, reduce the pollution of fly ash to the atmosphere, and improve the mechanical properties and durability of concrete. From the performance point of view, it must be blended in rubber concrete with tire rubber powder. The amount of fly ash can further improve the overall performance of the concrete.
1. Positive influence of fly ash on rubber powder modified concrete
Fly ash is fine ash collected from flue gas after combustion of coal. The main components are silica, alumina, iron oxide, ferric oxide, calcium oxide, cerium oxide, etc., mostly round particles. The application in the rubber powder modified concrete will be dispersed in the cement slurry, reduce the frictional resistance between the aggregate and the hydraulic cement, prevent the cement particles from sticking to each other, and release the mixing water retained in the cement particles. , to improve the slump of concrete mixture; the side of the vertebral body of the rubber powder modified concrete mixture mixed with fly ash does not have the problem of honeycomb and stone exposure, and the side of the vertebral body is basically free of slurry. Adhesion and water retention are improved.
2. The negative impact of fly ash on rubber powder modified concrete
The activity of fly ash at room temperature is lower than that of cement. The use of concrete will accelerate the hydration speed of cement slurry. The secondary reaction of cement hydration products cannot be fully carried out. Therefore, the addition of fly ash will reduce the cubic pressure resistance of concrete. Strength; however, the effect of fly ash on the compressive strength of concrete is not static. The secondary hydration reaction of fly ash will continue during the curing period of concrete, so the cubic compressive strength of rubber powder modified concrete Will improve.
It can be seen that the addition of fly ash to the rubber powder modified concrete can improve the slump of the rubber powder concrete mixture to a certain extent, improve the fluidity, water retention and cohesiveness of the concrete, thereby improving the concrete construction process; The addition of coal ash will reduce the compressive strength of concrete cubes. Therefore, when adding fly ash to rubber powder modified concrete, it is necessary to control its dosage reasonably and take certain measures to reduce or eliminate the fly ash to rubber powder concrete. Negative effects, as much as possible to improve the concrete construction process and overall performance.