Evaluation of Concrete Properties with Eggshell and Chicken Manure as Accelerating Additives

Abstract

Concrete, a composite material made from cement, aggregates, and water, is enhanced by the addition of chemical admixtures in small amounts just before or during mixing to improve its properties. From those Calcium nitrates is a commonly used chemical accelerator in the construction industry, which enhances the hydration process of cement and the early-age strength development of concrete. However, the extraction method of this admixture utilizing natural sources, such as limestone and fossil fuel, has led to concerns about resource depletion and its long-term environmental impact. To overcome these difficulties, exploring alternatives to nonrenewable calcium and nitrate sources becomes more important. The current study aims to produce calcium nitrate-based accelerator additive derived from eggshell and chicken manure and investigate its effects on various properties of C-30 concrete. Chicken manure from a poultry farm was treated by anaerobic digestion method with wheat straw to achieve the balance of carbon-to-nitrogen (C/N) ratio in the compost pile. Filtration and distillation were used in the experiment, and the Engineering Corporation of Oromia conducted a photometric test on the results, showing that nitrate (NO3) was 11.6 mg/L and nitrite (NO2) was 4.3 mg/L. Eggshells were also utilized for calcium ions (Ca2+ ) ions through solid-state reaction, resulting in 48.02% (CaO). The extracted solution was then used to obtain Ca(NO3)2 and Ca(NO2)2. The fresh and hardened concrete tests were conducted to evaluate the impact of this accelerating additive on workability, compressive strength, flexural strength, water absorption, and resistance to acid attack. Different dosages of the admixture (1%, 2%, 3%, and 4%) were tested. The experimental results showed that, with a 2% addition of the extracted additive, the compressive strength improved by 17.09%, 11.264%, 7.09%, and 7.48% at 7, 14, 21, and 28 days from the conventional concrete, respectively. The flexural strength also improved by 11.86%, 9.90%, and 12.31% at 7, 14, and 28 days from the conventional concrete with a 2% addition of extracted admixture. The water absorption was at its lowest at 3.03% with the 2% dosage. The FTIR results show that adding eggshell and chicken manure to the concrete mixture significantly alters its chemical composition. This may affect the performance and physical properties of the concrete. In terms of acid attack resistance, the conventional concrete experienced a 3.87% strength reduction, whereas the concrete with a 2% dosage showed a 4.7% reduction, indicating lower acid resistance compared to the control mix. While the extracted additive showed improved physical properties, further research may be needed to optimize the dosage levels for enhanced acid resistance without compromising other concrete properties.