The shard test and nanoporomechanics reverse classical paradigm of cement hydration being contractive.

Le Chatelier in 1887 and Powers in 1947 demonstrated that the volume of nanoscale C-S-H (calcium silicate hydrate) particles formed during hydration is smaller than the combined volume of the reactants-the anhydrous Portland cement and water. Hydration has thus been considered as contractive. An experiment shows that the opposite is true above the nanoscale.