Complex sentence: The liquid concrete is heavier than the bentonite slurry, and displaces it, and the bentonite slurry can subsequently be re-used in a new trench elsewhere on the construction site.
Split into simpler sentences: The liquid concrete is denser than the bentonite slurry, and therefore displaces it. The bentonite slurry can subsequently be re-used in a new trench elsewhere on the construction site.