Production of price-competitive bricks using a high volume of stone powder sludge waste and blast furnace slag through cementless CaO activation

Stone powder sludge is a waste by-product that is annually produced more than 7.5 million tons from the manufacturing process of crushed aggregates in Korea. This study investigated the use of stone powder sludge as a substitute for fine aggregate in brick manufacturing through the CaO activation of the ground-granulated blast-furnace slag (GGBFS) system, which was found to be more suitable than portland cement for the proposed bricks that contained a large quantity of stone powder sludge. This study also discussed the characteristics of leaching, hydration products, and microstructures of hardened samples of proposed mixtures. The trial bricks had high strength, low water absorption, and low material cost. Two of the proposed trial bricks satisfied the requirements of concrete building blocks, ASTM C55, for strength and water absorption at seven days of curing, while the cement brick, with the same quantity of stone powder sludge, failed to fulfill the requirement for water absorption.