Fresh and Hardened Properties of Self‐Leveling Mortars with Porcelain and Red Ceramic Wastes

Abstract

Self-leveling mortar (SLM) has several advantages when compared to the conventional mortar used in subfloors, especially when productivity is desired. In Brazil, the use of SLM is not still widespread related to conventional mortar. Few builders are using it in constructions. In the same way, the sustainable reuse of wastes in building materials is not so great, but it has grown, becoming increasingly important. In Brazil, a great amount of waste is generated by the manufacture of electrical porcelain insulators and red ceramic. These materials are formed mainly by amorphous silicates and aluminosilicates, which when added as cement replacement can generate pozzolanic reactions. The present study evaluated the feasibility of using such wastes to replace cement to make SLM. Mortars were studied in the fresh state (fluidity, segregation and/or bleeding, outflow rate, outflow time, and kinetics of temperature) and in the hardened state (compressive strength, flexural tensile strength, capillary water absorption, water penetration height, and air permeability). According to the results, the cement replacement by porcelain or ceramic in SLM diminishes the flow and increases the setting time. The compressive strength is higher than the minimum related to literature, and the low values of water absorption and permeability were reached with porcelain waste.

Performance evaluation of self-leveling mortars using phosphogypsum and white ceramic waste

“…For ceramics, similar results were found in the studies by Pereira and Camarini [4], who indicated that the 50% replacement of Portland cement with red ceramic did not significantly influence the cement hydration process, therefore, using the heat of hydration as an evaluation parameter can be a viable alternative.…”

“…However, like other cementitious materials, they require large amounts of cement, as they have an inverse relationship between workability and mechanical strength [3], making it difficult to obtain fluid mixtures with absence of exudation and/or segregation [4]. Aiming to modify the rheological properties of mixtures, chemical additives are used, raising the cost of these materials [5].…”

“…Associated with this context, one of the sustainability challenges in the civil construction industry is to reduce the use of cement due to the high amount of carbon dioxide (CO2) released into the atmosphere during the manufacturing process. For this, alternative materials that can reduce this environmental impact are sought [4], also aiming at a better performance and cost reduction [5], [6].…”

“…White ceramic waste can contribute to the performance of self-leveling mortars, as they are predominantly composed of silicon and aluminum, giving improvements in the pozzolanic activity index [4], [16] resulting in better mechanical properties, reduced heat of hydration, and shorter initial and final setting times [17].…”

“…The use of by-products and wastes in self-leveling mortars has been evaluated by other authors. Barluenga and Hernández-Olivares [18] used waste from slate mining; Wang and Jia [19] studied self-leveling mortars made with phosphogypsum, sulfoaluminate cement, and granulated blast furnace slag; Yang et al [5] evaluated self-leveling mixtures composed of phosphogypsum, Portland cement, sulfoaluminate cement, and different granulometries of fine aggregates; Pereira and Camarini [4] worked with porcelain and red ceramic waste from demolitions, replacing Portland cement in mass by 15%, 25% and 50%; and Mendes [20] studied self-leveling mortars with additions of 40% and 50% of marble and granite waste.…”