# Durability Issues and Corrosion of Structural Materials and Systems in Farm Environment
## 2 Agricultural Concrete and Metallic Structures  
[PERSON] and co-researchers [2] noted that steel reinforcements are commonly found in cow and pig precast concrete housing for pigs and cows, weaned (any weaned animal), and farrowing houses for pigs. Other common areas that are made of steel structures include downpipes, gutters, milking parlors, and partitions for cows and other domestic animals. Similarly, cast-iron and galvanized steel are commonly used to reinforce stalls for dairy cattle. In brief, metal reinforcements are integrated into different structures to improve the structural integrity of the concrete. The integration of steel into standard concrete structures exacerbates the risk of metal and concrete corrosion; this is because metals are highly susceptible to high humidity levels, temperature changes, and elevated concentrations of corrosive gases such as carbon dioxide (CO\({}_{2}\)) and hydrogen sulfide (H\({}_{2}\)S). However, metals react following exposure to chemicals, as noted in Table 1.  
The impact of different corrosive agents in Table 1 shows that corrosive gases, which are commonly found in silage and feed residues, accelerate corrosion through the formation of carbonic acid and sulphuric acid (in the presence of sulfate ions), respectively. The action of sulphuric acid and other corrosive agents on concrete structures is outlined below. Materials and chemicals that are responsible for corrosion in farm environments include pure water at a pH of 7. Water mainly originates from snow, spring water, morning dew, or rain [1; 2]. Water is associated with the dissolution of concrete and leaching into the microstructure. In addition to \begin{table}
\begin{tabular}{l c c c c} \hline \hline \multirow{2}{*}{**Metal Type**} & **Original Weight** & **The Average Rate of Metal** & **\% of Metal** & **Duration of Tests** \\  & **in g/cm\({}^{2}\)** & **Loss (g/cm\({}^{2}\)/month)** & **Remaining (mass)** & **(months)** \\ \hline \hline \multicolumn{5}{l}{Manure collection pit} \\ \hline BS & 1.0408 & 0.0184 & 13.6 & 49 \\ \hline ECS & 1.0462 & 0.0181 & 15.3 & 49 \\ \hline BG & 2.4963 & 0 & 100 & 49 \\ \hline GF-60 & 0.3283 & 0.0014 & 78.7 & 49 \\ \hline GF-90 & 0.3271 & 0.0008 & 87 & 49 \\ \hline SS & 0.6251 & 0.0003 & 97 & 49 \\ \hline DQ & 0.4272 & 0.0031 & 63.4 & 49 \\ \hline \multicolumn{5}{l}{Housing area} \\ \hline BS & 1.0408 & 0.0005 & 97 & 49 \\ \hline ECS & 1.0462 & 0 & 100 & 49 \\ \hline BG & 2.4963 & 0 & 100 & 49 \\ \hline GF-60 & 0.3283 & 0 & 100 & 49 \\ \hline GF-90 & 0.3271 & 0 & 100 & 49 \\ \hline SS & 0.6251 & 0 & 100 & 49 \\ \hline DQ & 0.4272 & 0 & 100 & 49 \\ \hline \multicolumn{5}{l}{Lagoon surface} \\ \hline BS & 1.0408 & 0.036 & 0 & 29 \\ \hline EC S & 1.0462 & 0.0298 & 0 & 35 \\ \hline BG & 0.63 & 0 & 100 & 49 \\ \hline GF-60 & 0.3283 & 0.0001 & 98 & 49 \\ \hline GF-90 & 0.3271 & 0 & 100 & 49 \\ \hline SS & 0.6251 & 0 & 100 & 49 \\ \hline DQ & 0.4272 & 0.0003 & 96.1 & 49 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Metal losses due to corrosion in swine manure environments [3]. “Reproduced with permission from [PERSON]; [PERSON], Bioresour. Technol. published by Elsevier, 1992”. water, inorganic acids--such as sulphuric acid, nitric acid, carbonic acid, and phosphoric acid--which originate from natural waters, chemical industry effluents have the potential to corrode the concrete structures. The extent of corrosion is influenced by the strength of the acid-acid dissociation constant (Ka) and pH. Diary areas and animal fodder silos, manure, and silage are among the lead sources of inorganic acids--such as oxalic, formic, tannic, lactic, and acetic acids--which dissolve into the concrete structures and mitigate the setting process [1; 2]. The carbonic acid formed poses a risk to the concrete and steel structures in the farm environment due to the transition to higher acidity values. Acid attacks impact the durability of farm structures. Corrosion of concrete structures can also be induced by oxalic and humic acids from chemical factories, contaminated ballast, and soils.