Volume 14, No. 2, 2020
Received: 2020/04/25, Accepted:
Authors:
U. Siva Rama Krishna; Ch. Naga Satish Kumar;
Abstract:
Ultra-thin white topping is a cement concrete overlay of thickness ranging between 50 mm and 100 mm over the bituminous pavement with surface failures gaining popularity in improving the long-term performance of the pavement. The use of supplementary cementitious materials (SCMs) in cement concrete pavements and overlays has high prominence in addressing the sustainability concept. In the present study, quaternary blended concrete mixes were studied for concrete overlay with a constant water-cement ratio of 0.4 to meet a minimum
modulus of rupture of 4.5 MPa.The optimization of these concrete mixes for maximum modulus of rupture with minimum dosages of silica fume (S), fly ash (F) and ground granulated blast furnace slag (G) was studied using genetic algorithms. The optimal solution regarding SCM materials for the developed non-linear regression model was obtained as S = 14.72%, F = 12.82% and G = 19.29%. Further, the durability and
microstructure studies were conducted on the optimized concrete mix, where it was concluded that the optimized concrete mix met the requirements for ultra-thin white topping concrete overlay improving the fresh and hardened properties of the concrete with enhanced durability and thus making the pavement concrete mix sustainable.
Keywords:
Supplementary cementitious materials, Ultra-thin white topping concrete, Ground granulated blast furnace slag (GGBS), Silica fume, Fly ash.