Production of Mixed Cement–Lime Mortars Incorporating Beige Bahia Marble Waste (BBMW) Filler and Construction and Demolition Waste (CDW)

Resumo

The civil construction sector consumes large volumes of non-renewable raw materials, especially in the production of hydraulic binders such as Portland cement and lime. The cement industry is one of the contributors to the worsening of the greenhouse effect due to the decarbonation of limestone and the use of fossil fuels, releasing large amounts of CO₂ into the atmosphere. At the same time, other stages of construction also cause changes in the landscape and generate significant amounts of waste in several segments, such as the extraction and processing of ornamental stones, which produce considerable waste ranging from block remnants to fine particulate material known as slurry. An alternative to mitigate these impacts is the partial replacement of binders with alternative materials in the formulation of mortars, which are widely used in different construction stages. Thus, this research aimed to evaluate the performance of mixed cement–lime mortars in which lime was partially replaced with Bahia Beige Marble Waste (BBMW) and Construction and Demolition Waste (CDW) at proportions of 10% and 20%, analyzing the physical–mechanical behavior of the mixtures. The materials used (cement, lime, BBMW, CDW, and sand) were characterized, and the water/binder ratio (w/b) was defined for the reference mixed mortar (1.00:0.5:6.90 — cement:lime:sand), using air-entraining and water-retaining additives, based on a flow of 260±5 mm. Subsequently, the w/b ratios were determined for each of the mixtures with lime replaced by 10% and 20% of BBMW or CDW. The results were compared with the reference mortar and showed a reduction in the water/binder ratio with the increase of waste content, in addition to greater cohesion of the mixtures. In the fresh state, mortars presented a reduction in bulk density with the use of both wastes. For water retention, there was a decrease with BBMW and an increase in this property in mixtures with CDW compared to the reference mortar. In the hardened state, the mortars showed improved flexural tensile strength and axial compressive strength. Therefore, based on the physical–mechanical results, both wastes, BBMW and CDW, demonstrated a predominantly physical effect of pore filling, favoring nucleation and improving physical–mechanical properties.