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Plain Cement Concrete (PCC)

Plain Cement Concrete (PCC) is a construction material that is commonly used for making foundations, floors, and other structural elements. It is a mixture of cement, fine aggregates (usually sand), and coarse aggregates (usually gravel or crushed stone) in a specific proportion. PCC is called "plain" because it is not reinforced with any steel bars or other reinforcement materials. It is simply a homogeneous mixture of cement, sand, and aggregates, which are then mixed with water to form a stiff paste. The paste is then poured into formwork, where it is allowed to set and harden. PCC is used as a base layer for many construction projects. It provides a flat and level surface for the construction of foundations, floors, and other structures. PCC is also used to cover up rough and uneven surfaces and to provide a smooth and level surface for finishing materials such as tiles or carpeting. PCC is relatively inexpensive compared to other construction materials, and it is easy to work with. However, it has low tensile strength, which means it can crack under tension. Therefore, PCC is usually used in compression, where its high compressive strength makes it a good choice for supporting heavy loads. There are different types of plain cement concrete (PCC) that can be used depending on the specific requirements of a construction project. Here are some common types of PCC: a) Nominal mix concrete: This type of PCC is made by using a nominal mix proportion of cement, sand, and coarse aggregates without any control on the proportions. b) Standard mix concrete: This type of PCC is made by using a pre-determined mix proportion of cement, sand, and coarse aggregates as per the standards set by the relevant authority or as per the project specifications. c) Designed mix concrete: This type of PCC is made by using a specific mix proportion of cement, sand, and coarse aggregates as per the design requirements of the project. It is generally used for high-strength concrete applications. d) Lean mix concrete: This type of PCC is made by using a lower proportion of cement and a higher proportion of sand and coarse aggregates. It is used for non-structural applications such as leveling courses or filling material. e) Rich mix concrete: This type of PCC is made by using a higher proportion of cement and a lower proportion of sand and coarse aggregates. It is used for high-strength applications such as the construction of columns, beams, and slabs. f) Reinforced concrete: This type of PCC is reinforced with steel bars or mesh to increase its tensile strength. It is commonly used in the construction of foundations, walls, and other structural elements. The choice of the type of PCC depends on the specific requirements of a construction project, such as the load-bearing capacity, durability, and aesthetics. The design considerations for plain cement concrete (PCC) depend on the specific requirements of a construction project, but here are some general factors that should be considered: a) Strength: The compressive strength of PCC is an important design consideration as it determines its load-bearing capacity. The required strength of PCC depends on the intended use of the structure and the loads it will be subjected to. b) Durability: PCC should be designed to resist environmental factors such as freeze-thaw cycles, chemical attacks, and abrasion. The durability of PCC depends on the quality of materials used, the curing process, and the protective measures taken. c) Workability: The workability of PCC refers to its ability to be easily mixed, placed, and compacted. The design should ensure that the PCC is workable enough to be placed and compacted without segregation or bleeding. d) Shrinkage: PCC is prone to shrinkage, which can cause cracking and other defects. The design should consider the amount of shrinkage and provide measures to control it, such as using low shrinkage aggregates, adding shrinkage-reducing admixtures, or providing adequate curing. e) Moisture content: The design should consider the moisture content of the aggregates and the required water-cement ratio to achieve the desired strength and workability of the PCC. f) Joint spacing: Joints are necessary to accommodate the thermal and moisture movements of PCC. The design should determine the appropriate joint spacing and the joint sealing materials to be used. g) Aesthetics: PCC can be used as a visible finish or as a base layer for other finishes. The design should consider the desired appearance of the PCC and provide measures to achieve the desired color, texture, and finish. The design considerations for PCC should ensure that the final product meets the required strength, durability, workability, and aesthetics while considering the specific site conditions and construction practices.