Recycled Aggregates Influence on the Mechanical Properties of Cement Lime-Based Mortars Part II

In the current framework of sustainable development, stricter international regulations are shaping waste management practices, particularly in the construction sector-one of the main generators of waste. This study investigates the reuse of deteriorated plaster waste from façades scheduled for rehabilitation, by partially replacing cement or aggregates in lime-cement mortars. Four mortar formulations were tested: a reference mix, one with 45% aggregate replacement by plaster waste, one with 10% cement replacement, and another combining the 45% aggregate replacement with polypropylene fibers. Both microstructural and macrostructural analyses were conducted to identify correlations between these levels when incorporating waste and fibers. Results show a decrease in compressive strength (36% for aggregate and 29% for cement replacement) and flexural strength (24% and 18%, respectively) as the replacement ratio increases. However, the inclusion of polypropylene fibers improved the mechanical performance. SEM analysis confirmed significant microstructural variations within the cementitious matrix due to waste incorporation. Despite reduced strength values, all mixtures remained within the limits defined by current standards, validating the feasibility of using plaster waste in mortars and emphasizing its potential to reduce construction waste and promote sustainable development.