Corrosion Evaluation of Geopolymer Concrete Made with Fly Ash and Bottom Ash

Abstract

Environmental pollution caused by CO2 releasing from the production of cement is a great challenge for the construction industry and has triggered exploration into more sustainable alternatives. Geopolymer Concrete (GPC) is a potential sustainable solution that does not involve the use of cement as a binder. GPC is produced by mixing the alumino-silicate source materials such as fly-ash with alkali activators such as potassium hydroxide (KOH) and potassium silicate (K2SiO3). Unlike Ordinary Portland Concrete (OPC), the characteristics of GPC depend on the precursor materials and therefore vary for different mixes. Consequently, corrosion behavior needs to be evaluated separately for individual mixes. This has narrowed the scope of existing published work on corrosion behavior of GPC. In this study, GPC and OPC specimens were prepared and exposed to accelerated corrosion exposure. Half-cell potential and linear polarization resistance were used to evaluate the corrosion rate in GPC and OPC. Under accelerated conditions, the corrosion rate of the GPC specimens was between 10 µm/year and 20 µm/year exhibiting a moderate to high rate of corrosion. Meanwhile, the corrosion rate of the OPC specimens was between 40 µm/year and 60 µm/year indicating a very high corrosion activity. It can be concluded that GPC has a higher resistance to chloride-induced corrosion; with a low corrosion rate and lower mass loss percentage, compared to OPC.

Influence of Liquid-to-Solid and Alkaline Activator (Sodium Silicate to Sodium Hydroxide) Ratios on Fresh and Hardened Properties of Alkali-Activated Palm Oil Fuel Ash Geopolymer

“…Geopolymers have become a green technology that is continuously developed by researchers as a cement replacement due to their similar binder characteristics and mechanical properties [ 1 , 2 ]. Using geopolymers instead of cement has benefits such as environmental friendliness (reduced use of cement), reduced CO 2 emissions , and reduced energy consumption [ 3 , 4 , 5 ]. Given the high demand for industrial construction materials, finding ways to prevent the scarcity of natural resources, aside from considering the usage of waste material in the construction industry, has become a main concern for the industry.…”

Recent Advances in Geopolymer Technology. A Potential Eco-Friendly Solution in the Construction Materials Industry: A Review

“…Low fluid permeability could prevent ions from crossing its structure; therefore, it has good resistance to Cl and sulfate (S) attacks, as well as good microstructural characteristics against shrinkage deformation, which help in reducing material cracking. Morla et al [68] compared the corrosion inertia of geopolymer concrete made of FA and bottom ash and PC concrete. By the linear polarization resistance test method, the geopolymer concrete corrosion rate ranged between 10 and 20 µm/year (moderate corrosion condition), while the corrosion rate of ordinary concrete ranged between 57 and 58 µm/year (very high-risk corrosion condition).…”

Predicting the Effect of Fly Ash on Concrete’s Mechanical Properties by ANN

“…Concrete, as one of the most important and most consumed construction material, which has a negative impact on the environment, needs to be considered in sustainable development. The amount of embodied CO 2 (ECO 2 ), i.e., the total amount of CO 2 produced in the extraction and transportation of raw materials and their manufacture into the final product, is directly compatible with cement content in concrete mix designs, since in the production process of Portland cement, a huge amount of energy is consumed, and a remarkable amount of CO 2 is produced [3][4][5]. The ECO 2 is stated as CO 2 produced per unit of volume or mass.…”