Final answer:
Hydraulic cement is the type of cement that expands upon mixing with water, sets quickly, and is used for repairing holes and cracks in foundations due to its fast setting and water-resistant properties.
Step-by-step explanation:
The type of cement that expands when mixed with water, hardens within minutes, and is commonly used to plug holes and cracks in foundations is hydraulic cement.
Unlike conventional concrete, which is a mixture of lime mortar, sand, pebbles, and water, hydraulic cements contain specific components that cause them to set quickly and become water-resistant. This property is essential for repairs in foundations where water exposure is a concern.
Historically, Roman concrete was one of the earliest known forms of hydraulic cement, containing a mix of volcanic ash and lime, allowing it to set underwater.
Modern hydraulic cements have evolved to offer even faster setting times and greater strength, making them ideal for urgent repair work where durability against moisture is required.