Concrete
Concrete names 2 different subjects across the 6 encyclopedias on this shelf. Each is set out below. 1 of them is described by more than one encyclopedia.
Concrete an artificial stone
Described by 2 of the 6 encyclopedias.
Aiton's Encyclopedia (1910)
an artificial stone. Builders' concrete of the present day is made of one part of Portland or hydraulic cement, three parts of sand, and six parts of crushed stone. The sharper, more angular, and clean the sand and stone, the better. These materials are mixed thoroughly with water, deposited either in molds to form slabs and blocks for curbing and paving, or else laid in the foundation or wall, and allowed to harden where the concrete is to remain. The ancient Babylonian, Egyptian, Greek, and Roman builders were familiar with this kind of material. The Romans, especially, employed concrete in the construction of foundations, piers, aqueducts, roadways, and bridges, portions of which still remain. In the early part of the nineteenth century the French constructed a breakwater to protect the harbor of Algiers. For want of quarry stone, blocks of concrete, weighing twenty-two tons each, were dropped into water fifty feet deep until they formed a long, irregular mole or protective wall. Concrete is used extensively in making a footing for brick or stone walls, especially in muddy, soft excavations where it is not practicable to reach bed rock. The foundation walls of the Chicago postoffice are supported in this way. Of late concrete slabs of superior quality have come into favor for sidewalks, and the cheapening of Portland cement has suggested the use of concrete for entire buildings. It is not unusual to use concrete blocks in place of cut stone for door sills, window sills, window caps, and the like. See Cement
Collier's New Encyclopedia (1921)
a composition used in building, consisting of hydraulic or other mortar mixed with gravel or stone chippings about the size of a nut. It is used extensively in building under water, for example, to form the bottom of a canal or sluice, or the foundation of any struc ture raised in the sea; and it is also fre quently used to make a bed for asphalt pavement, or to form foundations for buildings of any kind. It is used as the material with which the walls of houses are built, the concrete being run into moulds of the requisite shape, and then allowed to set. It is generally re-enforced with steel wire to strengthen it especially in open wall building. See CEMENT.
Concrete a technical term in logic
Collier's New Encyclopedia (1921)
a technical term in logic, applied to an object as it exists in nature, invested with all its attributes, or to the notion of such an object. Concrete is opposite to abstract. The names of individuals are concrete; those of classes, abstract. A concrete name is a name which stands for a thing; an abstract name is a name which stands for the attribute of a thing.
What Has Changed in the Last Century
Aiton's 1910 mix of one part Portland cement to three of sand and six of stone is still a recognisable recipe, and Collier's 1921 note that concrete is "generally re-enforced with steel wire" catches reinforced concrete just as it was taking over structural building. What neither could foresee was scale and refinement: Eugène Freyssinet's prestressed concrete, patented in the late 1920s, plus chemical admixtures and pumped delivery, made possible motorway networks, dams such as Hoover (1936), and towers like the Burj Khalifa. Concrete is now the most-used manufactured material on earth, and cement production alone accounts for roughly 8 per cent of global carbon dioxide emissions, which has turned low-carbon cements into a major research field. The Roman work both accounts admire is also better understood: modern analysis of pozzolanic ash and seawater mortars explains durability that Portland cement does not match. Collier's separate logical sense survives in philosophy, though its claim that names of classes are "abstract" would now be called a slip — class names are general, not abstract.
Written for this edition, 2026.