Repair mortars with water treatment plant sludge (WTPS) and sugarcane bagasse ash sand (SBAS) for more eco-efficient and durable constructions

Water treatment plant sludge (WTPS) and sugarcane bagasse ash sand (SBAS) can be used as fine aggregate in cementitious composites. This paper aims to evaluate carbonation depth, chloride penetration, steel corrosion probability, and corrosion rate of cementitious repair mortars produced with 3% WTPS and 30% SBAS. The results showed SBAS mortars have the best performance in relation to carbonation and chloride penetration tests. WTPS mortars have similar results to the reference sample. Both mixes with by-products were able to provide a more protective environment for steel reinforcement. They presented a delayed steel corrosion probability of 25% (for 3WTPS) and 113% (for 30SBAS) in comparison to the reference sample. This is due to increased alkalinity and refinement of pores given by incorporation of fine waste materials. Moreover, 3WTPS and 30SBAS can significantly reduce corrosion rates of steel reinforcement in the order of 70% and 97%, respectively. Therefore, 3WTPS and 30SBAS composites can be satisfactory used in jacketing repair mortars for more eco-efficient and durable constructions.