Development of alkali-activated mortar based on palm oil fuel ash and wood ash

Abstract

Alkali-activated materials are known by its fast development of high mechanical strength and high chemical stability, and the possibility to reuse waste in its formulation contributes to the reduction of several environmental impacts. The present developed an alkali-activated mortar based on palm oil fuel ash and wood ash. To this end, the physical and chemical characteristics of the materials were evaluated through tests of laser diffraction, x-ray diffraction and fluorescence, and thermogravimetry, followed by the formulation of binders by varying the CaO/SiO ₂ and SiO ₂ /Al ₂ O ₃ molar ratios. Six formulations were tested and metakaolin was used in two of them as a complementary source of Al ₂ O ₃ . After evaluating the mechanical properties of the binders, three mortars were formulated with a 25% and 50% variation in the volumetric aggregate content. Total strength development was observed in just 2 days, achieving an average flexural strength of 3.54 MPa and compressive strength of 10.5 MPa. The mortars showed low susceptibility to the development of efflorescence and an absorption rate of 9.6%, confirming the reuse potential of the ashes as precursors for the development of mortars.

Keywords:
Alkali-activation; Morta; Industrial ash; Residue