The effects of the thaumasite form of sulfate attack on skin friction at the concrete/clay interface

The paper presents the effects of thaumasite sulfate attack (TSA) on skin friction at the concrete/clay interface. Using clay-restrained conditions thaumasite formed attached to the concrete culminating in thaumasite layers of up to 24 mm depending on interface pH and applied pressure. Thaumasite at the interface did not decrease the shear strength including skin friction and cohesion. Therefore it was concluded that TSA occurring at piles or foundation bases does not affect the stability of the superstructure regarding loss of friction and settlements.