claim: Coins of the Swiss franc are used in trade.
evidence: For less common types of alkali-driven concrete degradation see alkali-aggregate reaction -LRB- disambiguation page -RRB- .. concrete degradation. concrete degradation. alkali-aggregate reaction. alkali-aggregate reaction. concrete. concrete. aggregate. Construction aggregate. The alkali -- silica reaction -LRB- ASR -RRB- , more commonly known as `` concrete cancer '' , is a swelling reaction which occurs over time in concrete between the highly alkaline cement paste and the reactive non-crystalline -LRB- amorphous -RRB- silica found in many common aggregates , given sufficient moisture .. concrete. concrete. cement. Portland cement. amorphous. amorphous. silica. silica. The expansion of concrete through reaction between cement and aggregates was first studied by Thomas E. Stanton in California during the years 1930 with his founding publication in 1940 .. concrete. concrete. cement. Portland cement. This reaction causes the expansion of the altered aggregate by the formation of a soluble and viscous gel of sodium silicate -LRB- Na2SiO3 · n H2O , also noted Na2H2SiO4 · n H2O , or N-S-H -LRB- sodium silicate hydrate -RRB- , depending the adopted convention -RRB- .. aggregate. Construction aggregate. gel. gel. sodium silicate. sodium silicate. This hygroscopic gel swells and increases in volume when absorbing water  : it exerts an expansive pressure inside the siliceous aggregate , causing spalling and loss of strength of the concrete , finally leading to its failure .. concrete. concrete. aggregate. Construction aggregate. gel. gel. hygroscopic. Hygroscopy. siliceous. Silicon dioxide. spalling. spalling. ASR can cause serious cracking in concrete , resulting in critical structural problems that can even force the demolition of a particular structure .. concrete. concrete. demolition. demolition