Compressive strength and microstructure of alkali-activated blast furnace slag/sewage sludge ash (GGBS/SSA) blends cured at room temperature

Compressive strength and microstructure of alkali-activated blast furnace slag/sewage sludge ash (GGBS/SSA) blends cured at room temperature M.M. Tashima 1* , L. Reig 2 , M.A. Santini Jr. 1 , J.C.B Moraes 1 , J.L. Akasaki 1 , J. Payá 3 , M.V. Borrachero 3 , L. Soriano 3 1 UNESP – Univ Estadual Paulista, campus de Ilha Solteira, SP- Brazil. MAC/UNESP – grupo de pesquisa em Materiais Alternativos de Construção. 2 EMC, Universitat Jaume I, Castelló de la Plana - Spain. 3 ICITECH - Instituto de Ciencia y Tecnología del Hormigón. GIQUIMA group, Universitat Politècnica de València. * Corresponding author: [email protected]; [email protected] Abstract In the present work, ground granulated blast furnace slag (GGBS) and sewage sludge ash (SSA) blends were assessed for the production of alkali-activated pastes and mortars. Percentages of SSA to substitute GGBS ranged from 0–30 wt.% and sodium concentrations of 6–10 mol.kg -1 were used for the activating solutions. Pastes and mortars were cured at 20 ºC for up to 90 days. Raw materials were characterised by granulometric analysis, XRF, XRD, FTIR and SEM techniques. The replacement percentage of GGBS by SSA and the sodium hydroxide concentration of the alkaline activator were optimised to produce mortar with compressive strengths close to 30 MPa after 28 curing days at room temperature. Best results were obtained in samples blended with 20 wt.% SSA activated with 6 mol.kg -1 NaOH solutions which, according to the XRD, FTIR and microscopic results, contained higher amounts of (N,C)-A-S-H gel. The potential use of SSA for the development of alternative cementitious materials at room temperature has been demonstrated. Keywords: Sewage Sludge Ash, Waste Management, Alkali-Activated Cement, Compressive Strength. Formatat: espanyol (alfab. internacional)

Compressive strength and microstructure of alkali-activated blast furnace slag/sewage sludge ash (GGBS/SSA) blends cured at room temperature

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sewage sludge ash

waste management

alkaliactivated cement

compressive strength