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:
“Love is at the root of all healthy discipline. The desire to be loved is a powerful motivation for children to behave in ways that give their parents pleasure rather than displeasure. it may even be our own long-ago fear of losing our parents’ love that now sometimes makes us uneasy about setting and maintaining limits. We’re afraid we’ll lose the love of our children when we don’t let them have their way.”
—Fred Rogers (20th century)
“In my dealing with my child, my Latin and Greek, my accomplishments and my money stead me nothing; but as much soul as I have avails. If I am wilful, he sets his will against mine, one for one, and leaves me, if I please, the degradation of beating him by my superiority of strength. But if I renounce my will, and act for the soul, setting that up as umpire between us two, out of his young eyes looks the same soul; he reveres and loves with me.”
—Ralph Waldo Emerson (1803–1882)
“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)