Tackling problems in civil engineering caused by the presence of pyrite

Abstract

Although the oxidation of pyrite in geological materials has been linked to various problems in civil engineering works for many years, the risk of further problems has not been eliminated. Pyrite occurs widely as a minor constituent of geo-materials and many construction processes result in the exposure of pyrite-bearing materials to air and water, which then result in oxidation. The paper presents an historical review of construction scenarios in which pyrite has had significant adverse impact. The cases considered include rapid deterioration of rock materials, chemical attack on concrete and metallic structures in the ground, and the expansion of fills and stabilized soils. These cases have been important turning points in understanding deleterious pyrite processes and the development of guidance for their avoidance. By following the guidance presented in the relevant standards and technical documentation, destructive processes due to pyrite should be avoided. However, as many of the problems are influenced by variables, such as site location factors and construction processes, adhering to published guidance may not eliminate the possibility of adverse impacts. It is important that expert technical advice is provided at all stages of projects and that any deviations from the expected performance should be properly evaluated.