Page 73 - New Trends in Green Construction

PERFORMANCE OF SELF-COMPACTING MORTARS MADE WITH GRANITE SLUDGE WASTE AS SUPPLEMENTARY SILICEOUS MATERIAL
Angélica Lozano-Lunar, Evgeny Dubchenko, Antonio Rodero, José Rarmón Jiménez, José María Fernández and Serhiy Bashynskyi
Keywords: Granite sludge waste, self-compacting mortar, supplementary siliceous material, mortar performance, Circular Economy,
1. Introduction
Ornamental stone (granite, marble, slate, etc.) is a material widely used in construction industry (floors, pavements, retaining walls, cladding, etc.). Granite blocks are cut into smaller sizes and during this process, a granite sludge waste (GSW) is generated, comprising splitter cooling water and the particles originated in stone processing (Rana et al., 2016). Overall, this waste has no are of usage and its accumulation in landfills lead to a heavy environmental impact especially due to its adverse effect on soil permeability and the crystalline silica percentage that, if inhaled, may cause lung diseases (Singh et al., 2016). The waste reuse in construction materials is the trend towards a new Circular Economy model. Therefore, GSW valorization as supplementary siliceous material (SSM) in the production of self-compacting mortars could contributes to the Circular Economy implementation at the construction industry reducing the raw material consumption and achieving the waste management.
2. Materials and methods
The self-compacting mortars were made with cement CEMI/52.5 R (CEM), siliceous filler (SF), siliceous sand (SS), super plasticizing additive and water. In addition, GSW was used, which particle size distribution allowed partial replacement of SF and SS. The siliceous aggregates were replaced by GSW in percentages of 0%, 20% and 40% by volume and the self-compacting mortar nomenclature was GSM0, GSM20 and GSM40, respectively. The Nepomuceno method was used to determine the self-compacting mortar dosage. The water/cement ratio (w/c) was set at 0.64, 0.66 and 0.68 for GSM0, GSM20 and GSM40, respectively. From each mix, prismatic specimens (40 mm x 40 mm x 160 mm) were manufactured and stored under climatic conditions (95% ± 5% relative humidity and 20 oC ± 2 oC of temperature) up to the test age. The self-compacting mortars performance was evaluated by compressive and flexural strength (UNE-EN 1015-11:2000), water absorption by capillarity (UNE-EN 1015-18:2003), open porosity for water (UNE 83980:2014) and shrinkage (UNE 83831:2010 EX).
3. Results and conclusions
The mortar's performance was not greatly affected by the GSW incorporation registering small differences compared to GSM0. The behaviour of all the studied properties was related to each other. The compressive strength and flexural strength values decreased slightly with the GSW increased in mortars (Table 1). GSW has particles with a more rough and angular texture than SF and SS which could increase the friction between the paste components, leading to a worse mortar compactness and whence opening the microstructure (Vijayalakshmi et al., 2013). This fact was in accordance with the slightly higher water absorption by capillarity and open porosity for water (Table 1) experimented in GSW mortars. The changes in shrinkage were minimal compared to the GSM0 (Fig. 1). The greatest difference in shrinkage was experimented in mortar with the highest
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New Trends in Green Construction