How does high moisture content in bricks affect adhesion with mortar?

High moisture content in bricks can lead to poor adhesion with mortar because excess moisture on the brick surface can create a barrier that prevents the mortar from properly bonding. When bricks are saturated, the water presents in the bricks may interfere with the hydration of the cement in the mortar, making it more difficult for the mortar to grip the brick effectively. This can result in weaker joints and diminished structural integrity over time.

In contrast, if bricks have an optimal moisture level, the mortar can adequately bond as it hydrates and cures. This optimal level allows for the necessary chemical reactions and mechanical interlocking that lead to a strong bond. Thus, maintaining appropriate moisture levels in bricks before laying them is crucial for achieving effective adhesion with mortar.