What common defect might you find in improperly mixed concrete?

Segregation of materials is a common defect that occurs in improperly mixed concrete. This phenomenon happens when the components of concrete, such as cement, aggregates, and water, separate during mixing, transporting, or placing. When concrete is mixed inadequately, it can lead to a non-uniform distribution of aggregates within the mix. Heavier particles may settle at the bottom, while lighter materials may float to the top, resulting in variations in both strength and durability throughout the structure. This non-uniformity can significantly impact the structural integrity and overall performance of the concrete, leading to weaknesses in areas where insufficient bonding or material density occurs.

While porosity, brittleness, and excessive shrinkage can indeed be issues associated with concrete, they are not as directly linked to the mixing process as segregation is. For instance, porosity tends to be more related to the water-cement ratio and curing conditions, rather than the mixing itself. Brittleness generally arises from the mix design or the quality of materials used, while excessive shrinkage is often attributed to a combination of drying conditions and the characteristics of the concrete mix, rather than improper mixing alone.