Concrete is a kind of integral engineering composite material which is made of cementitious materials (generally referred to as cement) to bond orthopedics (sand, stone) and water (including admixtures and admixtures) in a certain proportion. It is widely used in civil engineering and its resistance. The freezing performance directly affects the durability of the concrete. In the modern process production, a certain amount of tire rubber powder is added during the concrete processing process, which significantly improves the frost resistance of the concrete.
Concrete will produce a freeze-thaw cycle in a cold environment. The freeze-thaw cycle will generate internal stress in the concrete, causing expansion, resulting in cracks in the concrete and loose structure, resulting in surface peeling or collapse of the overall structure. As a typical elastomer, tire rubber powder has good compressibility and tensile deformation ability, and can generate a large deformation under the action of a large external force, which can provide a certain space for the expansion of concrete, thereby significantly improving the concrete. Frost resistance.
On the contrary, the concrete strength will decrease with the addition of the tire rubber powder. The result is that the joint surface between the tire rubber powder and the substrate is weak. The larger the amount of tire rubber powder, the more the weak interface in the overall concrete structure. This in turn reduces the frost resistance of the concrete.
Therefore, in the actual application process, when the tire anti-freezing performance is improved by the tire rubber powder, there is an optimum amount of the tire rubber powder: in general, the tire rubber powder added with 5% of the fine aggregate volume in the concrete can be maximally improved. The frost resistance of concrete; since the salt expansion rate is greater than the expansion caused by water freezing, the amount of tire rubber powder in the concrete can be appropriately increased during salt freezing, providing a larger expansion space for the concrete, generally the tire rubber powder The dosage is controlled to be about 10% of the volume of the concrete fine aggregate.
Every year, a large number of used tires are produced in the world. At present, in addition to tire retreading and production of recycled rubber, the main treatment methods for waste tires are to process used tires into tire rubber powder in various industries; add appropriate amount in concrete structure. Tire rubber powder can not only improve the frost resistance of concrete, improve the durability of concrete, but also consume a certain amount of used tires and alleviate the pollution problems caused by some used tires. It is a new concrete processing technology.