Performance of Fly Ash blended Crushed Sand Concrete

Achieving low permeability in concrete property is an important requirement for safety-related nuclear reprocessing plant structures. Towards this need, in view of the scarcity of river sand, M50 grade crushed sand (CS) aggregate concrete with controlled fines content and fly ash has been designed. This paper discusses workability, mechanical strength, chloride permeability and temperature rise due to heat of hydration aspects of fly ash blended crushed sand concrete used in five major plant buildings of a nuclear fuel reprocessing facility. Fly ash blended CS concrete has performed well and exhibited rapid chloride permeability values less than 750 coulombs. Statistical evaluation of 200 Nos. of fly ash blended CS concrete samples tested for compressive strength showed lesser standard deviation than that of same grade RS concrete samples. Temperature rise due to heat of hydration of fly ash replaced CS concretes measured for mass concrete is comparable to that of RS concrete. This paper reports the experience of the authors on the performance of low permeable fly ash blended crushed stone concrete during the construction of safety-related nuclear reprocessing plant structures and highlights how it exceeded the properties set viz. workability, compressive strength, modulus of elasticity, tensile strength and chloride permeation resistance.