Some unexpected effects of natural and anthropogenic chemicals on construction

From time to time chemicals present in the ground induce reactions that are sufficiently severe to cause structural damage, or risks to the health and safety of construction workers or end users of construction work. Such chemicals include those from contaminated land, which can complicate the design of underground works and may add significantly to costs. However, investigation techniques and remedial procedures are now well established for many contaminated land chemicals, and their effects should no longer come as a surprise to the construction team. In contrast, chemicals naturally present in the ground or deliberately introduced into it can lead to unexpected problems – especially if their effect is greatly out of proportion to their concentration in the ground. This paper gives brief case histories of some unanticipated effects of changes in redox potential associated with carbon, iron, nitrogen and sulfur species.