ACI Certification Practice Exam

Excessive water content in concrete can lead to segregation, which occurs when the aggregates (gravel, sand, etc.) separate from the cement paste. This separation can cause the heavier particles to settle at the bottom, leading to an uneven distribution of materials within the mix. As a result, the concrete's overall strength is compromised because the cement paste, which is crucial for binding the aggregates together, becomes diluted and less effective.

Moreover, the increasing water-to-cement ratio can lead to a higher porosity in the cured concrete. This means that more voids or air pockets are left in the concrete, weakening its structural integrity and making it more susceptible to cracking and other forms of damage over time. Additionally, a higher water content can also affect the concrete's durability, making it more vulnerable to environmental factors such as freeze-thaw cycles and chemical attacks.

In summary, while proper water content is essential for achieving the desired workability and strength, excessive water ultimately leads to segregation and reduced strength, which can severely undermine the performance and longevity of concrete structures.