**7. Effect of WWA Concrete on the Environment**

WWA can have a positive influence in developing cement from an environmental standpoint [92]. The mineralogical and physical assembly of burning ash, such as WWA ash, and the availability of metals depend on the treatment of temperature and feed material [93]. The last method for using waste wood ash must be appropriately sustained due to the fineness of particles and lenience of air pollution, which can lead to breathing issues for the public near the manufacturing places [50]. In addition to this impact, the impact of waste wood ash on acidic material can result in releasing heavy metals into the environment [67]. Thus, issues have to be raised and more studies must be performed on the environmental impacts of waste wood ash concrete. Udoeyo et al. [67] utilized waste wood ash as a mineral material to research its effect on the environment and revealed that, if the waste wood ash is discarded in lands, then acidic rain releases heavy metals to the surrounding area. Thus, the usage of waste wood ash decreases pollution by reducing the necessity of discarding [73].

Gorpade et al. [72] assessed the impact of the inclusion of waste wooden ash from 0% to 30% in concrete. It was revealed that up to 10% of cement can be efficiently substituted

with waste wood ash. If waste wood ash is utilized as a mineral material in concrete, the amount of discarded WWA and its adverse effects on the environment can be diminished significantly. Adding waste wood ash as a substitute for cement decreases the usage of cement in concrete, which reduces the manufacturing cost of binders and its related outflow of harmful gases. Waste wood ash is a very fine material compared to cement and it can fill all the voids within the microstructure of concrete, which makes it hard for the outside chlorides or salts to enter the concrete. Making concrete buildings near the sea areas with waste wood ash concrete is recommended to avert structure catastrophes from heavy salt-oriented climates [94].

Waste wood ash seems to be an auspicious pozzolanic material for the partial replacement of binder, with no reduction in concrete strength, with enhanced durability of sample, and contributing significantly to the sustainability of the construction industry [68]. Waste wood ash in samples help to makes an eco-efficient substitute cementitious material, which is efficient and cost-friendly [80]. Studies [70,95] have been performed to evaluate the creation of sustainable construction material by providing waste wood ash as a binder replacement material. The natural influence of the usage of waste wood ash in cement mortar, carbon impression, and the degree of consumed energy was taken as a major parameters that can be used as a quantitative limitation to signify the likely recompences of waste wood ash applications in cementitious materials. The study was carried out according to the exclusive method shown by Pavlikova et al. [69]. Waste wood ash can be an actual pozzolanic additive used as a partial substitute of cement to assist in the environmentally friendly concrete construction of buildings.
