Wood Ash as Sustainable Alternative Raw Material for the Production of Concrete—A Review

Abstract

Different ecological binders have been used to minimize the negative effects of cement production and use on the environment. Wood ash is one of these alternative binders, and there has been increasing research related to this topic recently. The wood ash utilized in the literature primarily originates from power plants and local bakeries, and predominantly wood fly ash is used. This review paper examines the use of wood ash as an ecological binder in two different applications: as a cement replacement and as an alkali-activated material. Studies have shown that while increased wood ash content in concrete and mortars can have negative effects on strength and durability, it is still a promising and developable material. Depending on the chemical composition of the wood ash, the strength and durability properties of concrete might be slightly improved by utilizing wood ash as a replacement for cement, with an optimal replacement level of 10–20%. However, there is a need for more research regarding the effects of wood ash on the durability of cement-based materials and its use in alkali-activated materials. Overall, this review provides a comprehensive overview of the properties of wood ash and its potential applications in conventional concrete and mortars, as well as in alkali-activated materials.

The Impact of High-Alkali Biofuel Fly Ash on the Sustainability Parameters of Concrete

“…With an increase in the BFA amount in the concrete specimens up to 20%, the compressive strength still remains higher than that of the control samples and reaches 50 MPa. It is important to note that the compressive strength results obtained in this study are up to 20-30% higher than those indicated by another author who used low-alkali BFA as a substitute for cement [13,35,47] and they are up to 10-20% higher than those indicated by another author who used ash with low alkaline content. The compressive strength started decreasing with the increase in the BFA amount to 30% and then dropped to 35 MPa.…”

“…The addition of fly ash allows for an increase in the chloride resistance of concrete [26] and shrinkage resistance [27] as well as a reduction in water absorption [28]. One review [35] highlighted that the optimal quantity of cement to be substituted depends on the chemical composition of BFA and the quantity of alkali compounds (K 2 O and Na 2 O). As generally indicated in several studies, the content of K 2 O and Na 2 O in BFA does not exceed 5% [4].…”

A Review: Construction and Demolition Waste as a Novel Source for CO2 Reduction in Portland Cement Production for Concrete

“…Wood ash [240,241], biomass ash [110], sugar filter mud [242,243], pulverized eggshell waste [244], bone ash [121], and pulverized oyster and scallop shell waste [245].…”

The Effects of Partial Replacement of Ground Granulated Blast Furnace Slag by Ground Wood Ash on Alkali-Activated Binder Systems

“…The cement industry is estimated to produce around 5-8% of global carbon dioxide emissions [4,5]. Depending on the energy sources used, the emissions from Portland cement production range between 500 and 900 kg CO 2 /t [6,7]. Portland cement is primarily made from limestone and clay.…”

“…Studies on the use of wood ash in environmentally friendly construction materials are increasing [29,35,38,40] and these studies were summarized in [7]. The utilization of wood ash as a partial Portland cement replacement has emerged as a promising application for mitigating the carbon footprint of the industry, at least for some applications.…”