This document discusses materials used for pre-stressed concrete, including high strength concrete and high tensile steel. It notes that pre-stressed concrete requires high compressive strength concrete with higher tensile strength than ordinary concrete. It also discusses that high strength concrete can achieve compressive strengths ranging from 70-100 N/mm2 without unusual materials. Regarding high tensile steel, it states that steel with slightly increased carbon content is generally used, and discusses strength requirements and permissible stresses in the steel. Proper protection of prestressing steel is also important to prevent corrosion.