Ready Mixed Concrete is a mixture of fine, coarse aggregates, and cement. These three ingredients are proportionally batched at a plant then transported in a truck at which it is mixed. Through a chemical reaction referred to as hydration, the concrete paste hardens to form what is known as concrete. Ready-mixed concrete is often remixed once it arrives at the job site to ensure that the proper slump is obtained. In the final process, materials, such as water and some varieties of admixtures are often added to the concrete at the job site after it has been batched to ensure that the specified properties are attained before placement.
Main components of Ready-Mixed Concrete
Cement: Portland Cement (Type 1-5), Blast Furnace Cement, Fly Ash Cement are types the most commonly used types of cement in the RMC production process.
Blast Furnace Slag: a vitreous byproduct of ore smelting, it is used in the concrete mixing process to increase the product’s strength, to decrease the product’s permeability and to increase its durability.
Fly Ash: residues generated from coal combustion of coal fired power plants; it is used as a pozzolanic substitute of Portland Cement. It is also capable of adding to the concrete’s final strength and increasing its chemical resistance and durability.
Water: water is mixed with aggregates and cement to induce a chemical reaction with will commence the hardening process. Iced water can also be applied to lengthen the curing process in situations of hot weather to prevent marring.
Aggregates: a mixture of granular materials such as sand, gravel, and crushed stones. Similar to cement and water, it is a key ingredient in the concrete production process. Gravels and sands are dug or dredged or recycled from previously used concrete mixture and then stored at the batch plant in a way that minimizes segregation and degradation to prevent contamination. The quality of these aggregates are key in determining the concrete’s hardened properties and thus the selection process and maintenance of aggregates are very important issues pertaining to the quality control of a batch plant.