During the mixing process, cement has the capacity to absorb more water than is actually needed for complete hydration. This excess water, not utilized in the chemical reaction, leaves behind voids within the cement paste as it hardens. These voids have a detrimental impact on the concrete’s strength and durability, creating pathways for the ingress of harmful substances and compromising its structural integrity.
High-quality concrete is distinguished by its minimal void content. This is achieved by ensuring that the water-cement ratio is optimized, minimizing the amount of excess water present in the mix. To evaluate this quality, water absorption tests are conducted on precast concrete pipes. This test assesses the concrete’s density and imperviousness, providing valuable insights into its ability to resist water penetration and chemical attack.
In essence, the presence of air voids in concrete serves as a critical indicator of its quality. By minimizing these voids through careful mix design and proper curing, engineers can significantly enhance the concrete’s strength, durability, and resistance to degradation.