Setting and Hardening
Cement sets when mixed with water by way of a complex series of chemical reactions still only partly understood. The different constituents slowly crystallise and the interlocking of their crystals gives cement its strength. Carbon dioxide is slowly absorbed to convert the portlandite (Ca(OH)2) into insoluble calcium carbonate. After the initial setting, immersion in warm water will speed up setting. Gypsum is added as an inhibitor to prevent flash setting.
Read more about this topic: Portland Cement
Famous quotes containing the words setting and, setting and/or hardening:
“it is finally as though that thing of monstrous interest
were happening in the sky
but the sun is setting and prevents you from seeing it”
—John Ashbery (b. 1927)
“One of my playmates, who was apprenticed to a printer, and was somewhat of a wag, asked his master one afternoon if he might go a-fishing, and his master consented. He was gone three months. When he came back, he said that he had been to the Grand Banks, and went to setting type again as if only an afternoon had intervened.”
—Henry David Thoreau (1817–1862)
“With sixty staring me in the face, I have developed inflammation of the sentence structure and definite hardening of the paragraphs.”
—James Thurber (1894–1961)