Performance of Anthill Soil Replaced Concrete in Sulfate Solutions

Durability of concrete is defined as its ability to resist any form of deterioration, allowing it to retain its original form and quality after it has been exposed to the environment of its intended use. Sulfate attack causes concrete to lose its compressive strength through the decomposition of the products of hydration of cement. Pozzolanic reactions from Supplementary Cementitious Materials (SCMs) help in resisting the sodium sulfate (Na2SO4) attack. This work investigated the potential use of Anthill Soil (AHS) to improve the performance of concrete in sulfate aggressive environments. An AHS replacement of 30% (per cent) by the weight of cement was used to make concrete test bars and cubes. The 0% replacement also referred to as the control was used as the point of reference from which all performances were measured. The specimens were immersed in 5% Na2SO4, 5% magnesium sulfate (MgSO4), and 5% mixed solution of Na2SO4 and MgSO4. Elongation measurements were taken over a period of 9 months, whereas compressive strength tests, which were used to work out the Strength Deterioration Factors (SDFs) and visual observations for surface deterioration were carried out at 9 months. From the results, AHS specimens that were immersed in the Na2SO4, MgSO4 and mixed Na2SO4 and MgSO4 solutions performed poorly in elongation compared with the control specimens, but had lower SDFs in the Na2SO4 and mixed solutions of Na2SO4 and MgSO4. The surface deterioration of AHS specimens in the MgSO4 solution was worse than that of the control specimens but was similar to that of the control in the mixed sulfate solution of Na2SO4 and MgSO4. The SDF results highlight the potential of using AHS with an advantage in Na2SO4 and mixed Na2SO4 and MgSO4 environments.