This section is from the book "A Practical Treatise On The Joints Made And Used By Builders", by Wyvill J. Christy. Also available from Amazon: Practical treatise on the joints made and used by builders.
This is used in street paving, the granite sets being laid and bedded on a coating of about 3 in. of gravel, spread over a foundation of hard material about 1 ft. in thickness. The joints between the sets are then filled in with asphalte, or a composition of creosote, pitch, and tar, in proportions varying according to the quality of the pitch, one variety of the mixture consisting of these constituents in the respective proportions of 1, 11, and 4 by weight. After boiling for a couple of hours the mixture is poured into the joints, consolidating the pavement and preventing the deposition of mud under the sets. With the same mixture blocks of wood or stone may be bedded and jointed to form paving, and joints in roadway planking under granite in iron bridges rendered water-tight, after all fissures and cavities have been stopped by caulking.
Previous to bedding the ground must be made up, consolidated, levelled, and covered with gravel to a depth of 3 in., more or less. Flags are bedded in mortar, paving bricks in mortar, and then grouted over and between the joints. Common tiles are laid in mortar upon a bed of lime core, brick rubbish, or coal ashes, not less than 3 in. thick, and grouted with cement. Superior tiles are laid upon a bed carefully floated, and laid to the proper fall, and grouted with cement, the excess being wholly washed off, so that none may be left to set on the surface. York or other stone paving, squared to shape, is bedded on mortar or cement, and set with joints as close as possible to preserve the courses. Kerbstones, gutter soles, and breast stones should be bedded on six inches of concrete, or more if on loose ground or where necessary, and the whole properly bonded, with broken and close joints well grouted and flushed solid, hydraulic lime only being used. Granite sets are bedded in first-class roads with close joints upon an inch or two of sand, overlying a bed of concrete some 12 in. thick. The concrete rests upon brick rubbish about 8 in. deep, rolled and bound with sand as a bottoming. Sets used for crossings require a thin layer of sand and 6 in. of concrete for a bed. Pitching on sea slopes is bedded on a layer of clay and small stones mixed, 12 in. thick. On sand the puddle requires protecting by a bed of rubble 18 in. thick.
One that is as close as possible consistent with the preservation of the courses and the irregularities of the edges and sizes of the stones, etc. In many instances, where grouting is depended on for filling up all crevices and consolidating beds and joints, it is fortunate that the roughness of the stones precludes too close a joint, which is rarely less than ¼ in. when sets are used. Wood paving, to be safe, requires close joints not less than ⅜ in. in width, otherwise dirt accumulates within them and renders the surface dangerously greasy.
This occurs in paving with granite sets, which, after being laid as closely as possible, are covered with clean, screened, dry, hard gravel, well brushed and worked into the joints. The sets should then be rammed and more gravel similarly applied, and the operation repeated again if necessary to attain thorough compactness and solidity. The same kind of joint does well for carriage-way paving in yards, etc, composed of larger stones, laid close and bedded on a few inches of rough ballast.
The joints between granite sets or cubes are grouted with thin hydraulic lime grouting, or liquid mortar, after ramming, and then covered with a coating, a full inch thick, of fine clean gravel. "Wood pavement is sometimes grouted with hydraulic lime and sand, the joints being occasionally partially filled with asphalte previous to grouting, or the joints between wood blocks impregnated with creosote may be run with a mixture of pitch and creosote in the proportion of 1 cwt. of the former to 1 gallon of the latter, alternated two or three times with coats of fine gravel.
Racked Joint is produced by filling up the joints between paving sets with small broken stones or fine gravel.