Lime is prepared by crushing limestone, heating it to 2000°F to release CO2, resulting in calcium oxide. When mixed with water, lime sets slowly over time by absorbing carbon from the air to form calcium carbonate. Lime is used for soil stabilization, masonry, plaster, and purifying water. It is cheaper than cement but possesses less strength and sets more slowly. Cement is more brittle, sets rapidly when mixed with water, provides high strength, and can be used for important structures, but is more expensive than lime.