|
 |
 |
|
Burlap Cement: The resulting cement, produced from the formerly discarded grappiers, was of much higher quality than that obtained from the unsintered material. This fact was firmly established by the English cement manufacturer L. C. Johnson in 1845, and the term "portland cement" has since been applied solely to the cement made from the sintered material. This period marks the real beginning of the portland cement industry.
Another great aid in checking erosion before the grass is established is to cover the new planting with an open weave fabric, sold by dealers in horticultural supplies under the name of Erosionet. This is pegged securely in place and may be allowed to remain and rot or may be taken up when the grass is two and a half inches tall.
Instead of Erosionet you may use cheesecloth or burlap cement but these must be removed as soon as the shoots are half an inch long. This necessitates watching the young grass carefully. Don't use burlap cement that is too heavy. Twenty gauge or seven and a half ounce grade is satisfactory. Lap the strips slightly and fasten them down with large nails spaced about three feet apart. Choose a cloudy day if possible for removing the burlap cement, or at least do it late in the afternoon, so that tender shoots are not suddenly exposed to scorching sun. Following removal of the burlap cement a good watering with a fine spray offsets ill effects to a considerable degree. Pick up all nails. They can seriously damage the blades of a mower!
The production of portland cement is a major industry in the United States, increasing from 8 million barrels (1.4 million metric tons) in 1900 —when it trailed natural cement slightly in output—to almost 400 million barrels (68.4 million metric tons) annually. (A 376-pound, or 171-kg, barrel is the standard unit of weight for hydraulic cement in the United States, even though no cement, except for export, is now shipped in barrels. The 94-pound, or 42.7-kg, bag now in general use contains one fourth of a barrel.) The leading cement-producing countries are the United States, the USSR, West Germany, Japan, and France. |
|
|
| |
|
|
|
|
