Title : DURABILITY OF CONCRETE: A CASE STUDY OF AN OFFICE BUILDING WITH POST TENSIONED SLAB
Authors : Dr K M Soni and Bharat Kataria
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Price : 250
Abstract : A durable concrete is one that performs satisfactorily in the working environment during its anticipated exposure condition during its life cycle. Durability of concrete in a RCC structure depends upon its constituents viz cement, aggregates, admixtures, water, air, reinforcement and cover to the reinforcement used in concrete. With adverse atmospheric conditions and reactive agent present in cement, aggregate, water or admixtures reacts with the reinforcement under favourable conditions, and corrosion starts in the reinforcement leading to spalling of concrete affecting the durability. Cracks, carbonation, permeability, and harmful chemicals further enhance the corrosion. Post tensioning in slabs provides higher cover to strands as compared to conventional RCC. The Galvanized or lead coated sheathing further protects strands from corrosion. Also, duct filled with cement grout has lesser chances of air entry. Post tensioning being a specialized work also ensures proper quality in field. Thus, post tensioning helps in durability of concrete. An office building having 2 basements + ground + 13 floors in Bandra Kurla Complex (BKC) area in Mumbai is selected as a case study focusing the advantages of post tensioning on durability of concrete. Structural glazing has been provided in the building to avoid direct exposure to the environment. In post tensioning, steel strands have been provided in sheathing with grout vents at both ends. Stressing has been done when concrete gained required strength and the duct/sheath has been filled with cement grout.