South Africa, officially the Republic of South Africa, is the southernmost sovereign state in Africa. It is bounded on the south by 2,798 kilometers of coastline of southern Africa stretching along the South Atlantic and Indian Oceans, on the north by the neighbouring countries of Namibia, Botswana and Zimbabwe, and on the east by Mozambique and Swaziland, and surrounding the kingdom of Lesotho. South Africa is the 25th-largest country in the world by land area, and with close to 53 million people, is the world's 24th-most populous nation. It is the southernmost country on the mainland of the Old World or the Eastern Hemisphere.
South Africa is a multiethnic society encompassing a wide variety of cultures, languages, and religions. Its pluralistic makeup is reflected in the constitution's recognition of 11 official languages, which is among the highest number of any country in the world. Two of these languages are of European origin: Afrikaans developed from Dutch and serves as the first language of most white and coloured South Africans; English reflects the legacy of British colonialism, and is commonly used in public and commercial life, though it is fourth-ranked as a spoken first language.
A cement is a binder, a substance that sets and hardens and can bind other materials together. The word "cement" can be traced back to the Roman term opus caementicium, used to describe masonry resembling modern concrete that was made from crushed rock with burnt lime as binder. The volcanic ash and pulverized brick supplements that were added to the burnt lime, to obtain a hydraulic binder, were later referred to as cementum, cimentum, cäment, and cement.
Cements used in construction can be characterized as being either hydraulic or non-hydraulic, depending upon the ability of the cement to set in the presence of water (see hydraulic and non-hydraulic lime plaster).
Non-hydraulic cement will not set in wet conditions or underwater; rather, it sets as it dries and reacts with carbon dioxide in the air. It can be attacked by some aggressive chemicals after setting.
Hydraulic cements (e.g., Portland cement) set and become adhesive due to a chemical reaction between the dry ingredients and water. The chemical reaction results in mineral hydrates that are not very water-soluble and so are quite durable in water and safe from chemical attack. This allows setting in wet condition or underwater and further protects the hardened material from chemical attack. The chemical process for hydraulic cement found by ancient Romans used volcanic ash (activated aluminium silicates) with lime (calcium oxide).
Cement (Russian: Цемент) is a Russian novel by Fyodor Gladkov (1883–1958). Published in 1925, the book is arguably the first in Soviet Socialist Realist literature to depict the struggles of post-Revolutionary reconstruction in the Soviet Union.
The protagonist, Gleb Chumalov, is a returning Red Army soldier hero who after the Russian Civil War comes back to a hometown in painful transition and to its cement factory being reorganized for the massive new Soviet effort. His wife, Dasha, plays the role of the Soviet "new woman," and Gleb finds he cannot easily pick up the threads of their old relationship. The novel is Gladkov's best known work because of its portrayal of the sociological effects of early Communism, especially after the sexes are suddenly decreed equal in the labor force of the local cement factory.
A Red Soldier returns home from the war victorious, eager to return to his wife, comrades, and factory, only to find out that the Revolution is in shambles, and that the country is in famine despite food rations. When he left three years earlier, Revolution was in the air. Now his wife's heart has hardened, his comrades no longer recognize him, and the factory is deserted, stripped bare by the starving citizens. Nearly everyone has abandoned the Revolution, and icons of the revolution collect dust, neglected. Only a few have remained loyal to the Revolutionary ideals. These few serve as examples of the ideal socialist citizen, but there are too few of them and a socialist state requires the masses to operate the machine of the socialist cause.
Cement is a material for bonding stone or brick.
Cement may also refer to: