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Both physical damage and chemical attack of concrete in sewage and septic systems is possible. However, chemical attack is much more prevalent and has two primary causes: acid attack and sulfate attack. In the wastewater industry, the acid attack mechanism is normally referred to as Microbial Induced Corrosion (MIC) – a process in which sulfides in the waste water stream are transformed by biological reactions into sulfuric acid. The sulfur compounds produced by this reaction penetrate the concrete substrate helping to initiate sulfate attack.

Elevator pits—the concrete boxes that sit at the bottom of the shaft below the elevator cars—are a simple structural system but can be highly susceptible to water intrusion, which will directly affect the structural and mechanical integrity of the elevator system. The following whitepaper evaluates various elevator pit waterproofing methods based on their reliability, accessibility and long-term durability. Particular emphasis is placed on crystalline waterproofing and its application as a long-term solution in new construction and remedial repair techniques for existing elevator pits.

The sustainability of a concrete structure is inextricably tied to both its strength and durability and can be defined as environmental impact over lifetime performance. By increasing the performance of concrete and its service life and decreasing its environmental impact the sustainability of a concrete structure will be increased.