Leaching Characteristics of Wood Biomass Fly Ash Cement Composites

Abstract

Wood biomass ash (WBA) represents an environmental and economic problem for energy producers, and there have been extensive studies of using WBA as a raw material in construction products. This study investigates the leaching characteristics of WBA cement composites based on testing results. Currently, 70% of WBA is landfilled, and the rest is primarily used in agriculture; therefore, this study also addresses the leaching as a component of environmental safety of these two primary WBA management approaches. An analysis of the leaching characteristics of WBA, monolithic, and crushed cement composites is performed by replacing 15% of the cement with WBA. The study was conducted using three WBA samples collected from different power plants. Increased values of leaching from the WBA itself are indicative of potential issues that could occur in the case of its disposal. The study concluded that the WBA could be potentially environmentally acceptable as a raw material in the concrete industry because the heavy metals are stabilized within the cement matrix.

Pilot Scale Production of Precast Concrete Elements with Wood Biomass Ash

“…The chemical composition of the WBAs and cement used in the concrete mixes were compared with the criteria for coal fly ash according to the standard EN 450-1:2013 [ 55 ], Table 5 . According to the results of chemical analysis, the properties of WBA differ significantly from those of coal fly ash, a traditionally known and widely used mineral admixture [ 37 ]. It is also important to emphasize that the chemical composition of WBA can vary significantly depending on the raw material and combustion technology [ 26 , 56 , 57 , 58 ].…”

“…In addition, when waste ash is landfilled in non-designated sites, there is also the problem of groundwater pollution due to leaching of heavy metals from WBA or rainwater infiltration, all of which have a negative impact on the ecological system [ 36 ]. Therefore, by binding the heavy metals from WBA in the cement matrix, the use of WBA in low-carbon concrete contributes to the production of an environmentally friendly and cost-effective alternative cementitious material [ 37 ]. To verify an optimum share of WBA as a cement substitute, which has exhibited promising pozzolanic properties, a compromise between the amount of WBA and the downgrade of concrete properties is needed [ 38 , 39 , 40 , 41 ].…”

Utilization of Wood Biomass Ash in Concrete Industry

“…The authors [25,41,64] found that the concentration of heavy metals such as Zn, Cd, Pb, and Hg is higher in fly WBA samples than in bottom samples. Therefore, the leaching/stabilization behavior of cementitious composites prepared with fly WBA Values of cumulative leaching in mg/m 2 for different metals (M-Fi-mortar mix with 15% of fly WBA) [65].…”

“…Utilization of Wood Biomass Ash in Concrete Industry DOI: http://dx.doi.org/10.5772/intechopen.102549 should be analyzed. According to the leaching results obtained by the author [65] for the observed heavy metals (Zn, Cd, CR, Cu, Ni, Pb) on monolithic specimens using 3 types of fly WBA (Figure 6), it was concluded that the leaching of heavy metals was acceptable, i.e., less than the limits according to the Dutch guidelines of the Soil Quality Ordinance [66] (limits for finished building materials according to the Soil Quality Ordinance for Cd: 3.8 mg/m 2 ; Cr: 120 mg/m 2 ; Cu: 98 mg/m 2 ; Ni: 81 mg/m 2 ; Pb: 400 mg/m 2 ; Zn: 800 mg/m 2 ). The same was confirmed by the authors [55,67] when using ash from the combustion of pure wood biomass.…”

“…Figure 6.Values of cumulative leaching in mg/m 2 for different metals (M-Fi-mortar mix with 15% of fly WBA)[65].…”