Low shrinkage, minimum creep characteristics and a high value of young?s modulus are generally deemed necessary for concrete used for prestressed members and loss of prestress in steel reinforcement is minimum because elastic and creep strain are very small due to high modulus of elasticity.

The covers may be reduced to 15mm provided that nominal maximum size of aggregates does not exceed 15mm and nominal cover provided for moderate steel is 30mm or size of cable in case of protected post tensioned members are exposed to an aggressive environment, se cover requirements are increased by 10mm.

The minimum 28 day cube compressive strength prescribed in Indian standard code IS 1343-1980 is 45n/mm² for pretensioned members and 35n/mm² for post tensioned members with development of vibration techniques in 1930, it became possible to produce without much difficult, high strength concrete having 28 day compression strength in range of 30-70n/mm².

High tensile steel are commonly used in prestressed concrete members and ultimate strength of high tensile steel is equal to 2100n/mm², refore losses of prestress due to shrinkage and creep with a stress of 200n/mm² are restricted.

The degree of workability relating to compaction factor value is 0.80 for Indian standard method design for high strength concrete mix, steps involved in Indian standard method is target mean strength, water cement ratio, maximum size of aggregates, degree of workability, considering all factors cement content is obtained.

Recent developments in field of concrete mix design have indicated that it is now possible to produce even ultra high strength concrete, of any desired 28 day cube compressive strength ranging from 70-100n/mm² without taking resource to unusual materials.

In order to prevent hydrogen embrittlement, it is essential that steel is properly protected from action of acids and wires should be protected from rain water and excessive humidity by storing m in dry conditions.

Reinforcement cover is provided according to codal provision IS:1343-2012 and it is essential to provide because it leads to corrosion, protecting steel from fire etc, consequences of providing cover more than requirement leads to increase in width of cracks and weight of structure.

In Erntroy and Shack lock?s empirical method high strength concrete mixes are designed by using empirical graphs relating compressive strength to reference number for concrete made with crushed Granite, coarse aggregates and irregular gravel and range of degrees of workability varying from externally low to high corresponds to compacting factor values of 0.65 and 0.95.

As per IS:1785-1983, nominal size of cold drawn stress are 2.5, 3, 4, 5, 7 and 8mm diameter and to improve properties of wire, y have to be tempered by heating wires at 150 to 480 degrees, which enhances tensile strength.