Development of a Commercial Screed Mortar with Low OPC Content by Incorporation of Biomass Fly Ash

Abstract

Substitute Ordinary Portland Cement (OPC) by biomass fly ash (BFA) reduce the environmental impact produced by cement-based materials, and at the same time, decreased the economic and environmental burden associated with the landfilling of this waste. This study aims to evaluate the recycling of BFA as supplementary cementitious materials (SCMs) in a commercial screed mortar formulation. Two BFA varieties, both resulting from fluidized bed combustion of forest residues, were used to replace 17, 50, and 67 wt.% of OPC. The influence of simple pre-treatment processes of the BFA, such as sieving and grinding, in the fresh and hardened state properties of the mortars, was evaluated. The BFAs were characterized in terms of chemical (XRF) and mineralogical (XRD) composition, particle size distribution (laser diffraction-COULTER) and morphology (SEM). The prepared formulations were characterized in terms of workability, mass loss upon curing, bulk density, sorptivity (by immersion and capillary), flexural and compressive strength and durability to 25 freeze–thaw cycles. Both of the BFAs are potential SCMs. Substitution of 17 wt.% OPC with BFA complied with the product technical requirements for compressive and flexural strength (10 and 3 MPa, respectively), with the ground and sieved and just sieved BFAs perform slightly better than the as-received BFA.

Valorization of Kraft Pulp and Paper Mill Slaker Grits and Biomass Fly Ash as Fillers in a Commercial Screed Mortar Formulation

“…The XRD pattern of the BFA samples shows that α-quartz (α-SiO 2 ), calcite (CaCO 3 ), microcline (KAlSi 3 O 8 ), and muscovite (KAl 2 (AlSi 3 O 10 )(OH) 2 ) are the main crystalline detected phases. These findings are in line with the results obtained in XRF and with the crystalline phases reported in the literature (quartz and calcite) [ 4 , 13 , 14 , 15 ]. When qualitatively comparing the BFA1 and BFA2 diffractograms with those of the sieved fractions (BFA1_S and BFA2_S), it is possible to observe that the peaks referring to α-quartz decrease in intensity.…”

“…Their surface is generally rough and not strongly vitreous. These morphology features fit the descriptions made by other authors [ 4 , 15 , 16 , 17 ].…”

“…It was assumed that the chemical composition and the LOI of BFA1_GS and BFA2_GS were maintained as equal to their parent samples, BFA1 and BFA2, respectively, because no amount of those powders was wasted during the applied pre-treatments. Other studies also pointed to SiO 2 and CaO as the major oxides present in fly ash generated from biomass combustion in bubbling fluidized bed boilers [ 4 , 13 , 14 , 15 , 16 ]. The observed compositional differences between the two sorts of BFA can be a consequence of variations in the biomass used as fuel [ 16 ].…”

“…Biomass fly ashes (BFA) are removed from the flue gases, and bottom bed ashes are generated by the periodic bed discharges. In the literature, various studies report the development of cement-based materials with BFA incorporation as supplementary cementitious material [ 4 , 5 , 6 , 7 ], as aggregate replacement [ 8 ], or as filler [ 7 , 9 , 10 ]. In the present work, the valorization of BFA as a filler was evaluated.…”

Valorization of Fly Ashes and Sands Wastes from Biomass Boilers in One-Part Geopolymers

“…In the literature, investigations with biomass fly ashes are scarce. However, recently, Capela et al (2021) [ 9 ], studied the use of FA biomass as a partial substitute for OPC (0 to 67 wt.%) and studied the influence of pretreatments on the properties of the prepared mortars. The authors demonstrated that the replacement of 17 wt.% of OPC by as received FA does not affect the properties of the specimens, which resisted up to 25 freeze–thaw cycles.…”