Concrete is a widely-used construction material that is made by mixing cement, sand, coarse aggregate, and water. However, there are different types of concrete that can be used for specific purposes. Lightweight concrete is commonly used in high-rise buildings as it reduces weight through the use of lightweight aggregates like expanded shale, clay, or perlite. On the other hand, high-strength concrete is used in durable applications like bridges and parking garages due to its higher compressive strength, which is achieved by a lower water-to-cement ratio and additional cement/chemical admixtures.