Fresh concrete refers to concrete that has just been mixed and is still in a plastic or workable state. Hardened concrete refers to concrete that has undergone the curing process and has reached its final strength and durability. Here are some properties of fresh and hardened concrete:
Properties of fresh concrete:
Workability: This refers to the ease with which concrete can be placed, compacted, and finished. It depends on the water-cement ratio, the amount of cement and aggregate, and the use of admixtures.
Bleeding: This is the process in which water is separated from the other components of the concrete mixture and rises to the surface. Bleeding can affect the durability and strength of the hardened concrete.
Setting time: This is the time it takes for the concrete to harden and become firm. It depends on the type of cement used, the water-cement ratio, and the temperature and humidity conditions.
Segregation: This is the separation of the coarse and fine aggregates in the concrete mix due to excessive vibration or improper compaction.
Properties of hardened concrete:
Compressive strength: This is the ability of the concrete to resist compression or crushing. It is a measure of the concrete's ability to support loads and is typically tested after 28 days of curing.
Tensile strength: This is the ability of the concrete to resist tension or pulling apart. Concrete has low tensile strength and is often reinforced with steel bars or fibers.
Durability: This refers to the ability of the concrete to withstand environmental factors such as freeze-thaw cycles, exposure to chemicals, and abrasion.
Permeability: This is the ability of the concrete to allow water or other fluids to pass through. Low permeability is important for preventing water damage and corrosion of steel reinforcement.
Shrinkage: This is the reduction in volume of the concrete due to the loss of moisture during the curing process. Excessive shrinkage can cause cracking and reduce the durability of the concrete
Comments
Post a Comment