Mastic asphalt is a dense, impermeable mixture of asphalt binder and fine aggregates, commonly used in flooring, waterproofing, bridge decks, and road surfaces due to its durability and workability. Testing its hardness is essential for quality control, ensuring it meets performance standards for consistency and resistance to deformation under load. The hardness number quantifies the material’s resistance to penetration, which is critical for applications where the asphalt must withstand traffic or environmental stresses.