Aggregate: Sand, gravel, shell, slag, or crushed stone used in base materials, mixed with cement to make concrete, or with asphalt.
Base or Base Course: A material of a designed thickness placed under the surface wearing course of paving units and bedding course. It is placed over a sub-base or a subgrade to support the surface course and bedding. A base course can be compacted aggregate, cement or asphalt stabilized aggregate, asphalt or concrete.
Bedding Sand or Bedding Course: A layer of coarse, washed sand screeded smooth for bedding the pavers. The sand can be natural or manufactured (crushed from larger rocks) and should conform to the grading requirements of ASTM C 33 or CSA A23.1 with limits on the percent passing the No. 200 (0.075 mm) sieve. A screeded sand layer is 1 to 1 1 / 2 in. (25 to 40 mm) thick.
Blending Pavers: Mixing colored concrete pavers from three or four cubes to insure an even color distribution.
Coarse Aggregate: Aggregate predominantly retained on the U.S. Standard No. 4 (4.75 mm) sieve; or that portion of an aggregate retained on the No. 4 (4.75 mm) sieve.
Compaction: The process of inducing close packing of solid particles such as soil, sand, or aggregate.
Concrete Pavers: Concrete paving units, rectangular, square or dentated, capable of being placed with one hand into a laying pattern. The surface area is typically 100 in. 2 (0.065 m 2 ) and the overall length to thickness is 4 or less. Compare to Paving Slab.
Crushed Stone: A product used for pavement bases made from mechanical crushing of rocks, boulders, or large cobblestones at a quarry. All faces of each aggregate have well-defined edges resulting from the crushing operation.
Dry Mix Joint Sand Stabilizer: Joint sand treated with chemicals that when placed in contact with water, activates them to bind together the sand particles. This stabilizes the joint sand, reduces its permeability, sand loss and helps prevent weeds
Edge Restraint: A curb, edging, building or other stationary object that contains the sand and pavers so they do not spread and lose interlock. It can be exposed or hidden from view.
Efflorescence: A white deposit of calcium carbonate on concrete surfaces. It results from the reaction of calcium hydroxide with carbon dioxide from the air. The calcium hydroxide is a byproduct when cement hydrates. It is slightly soluble in water and migrates to the surface through capillary action. The calcium hydroxide remains on the surface, reacts with carbon dioxide, which forms calcium carbonate and water. This conversion, depending on weather conditions, will dissipate over time. Calcium carbonate is the most common type of efflorescence. The presence of efflorescence does not compromise the structural integrity and is not indicative of a flawed product.
Erosion: The process of wearing away soil by water, wind, ice and gravity; also the detachment and movement of soil particles by the same forces.
Finished Grade: The final elevation of a soil, base, or pavement surface which is often indicated on construction drawings. Also Finish Elevation.
Geogrids: Geogrids are two dimensional or three dimensional. The two dimensional type are flat and have small, “TV screen” shaped openings. The material is generally placed between the soil and the base to reduce rutting. Three dimensional geogrids are 4 to 8 in. (100 to 200 mm) high and provide stability under loads for cohesionless soils.
Geotextiles: Woven or non-woven fabrics made from plastic fibers used for separation, reinforcement, or drainage between pavement layers.
Gradation: Soil, sand or aggregate base distributed by mass in specified particle-size ranges. Gradation is typically expressed in percent of mass of sample passing a range of sieve sizes. See ASTM C 136.
Grade: (noun) The slope of finished surface of an excavated area, base, or pavement usually expressed in percent; (verb) to finish the surface of same by hand or with mechanized equipment.
Gravel: Rounded or semi-rounded particles of rock that will pass a 3 in. (75 mm) and be retained on a No. 4 (4.75 mm) U.S. standard sieve which naturally occurs in streambeds or riverbanks that have been smoothed by the action of water. A type of soil as defined by the Unified Soil Classification System having particle sizes ranging from the No. 4 (4. 75 mm) sieve size and larger.
Herringbone Pattern: A pattern where joints are no longer than the length of 1 1 / 2 pavers. Herringbone patterns can be 45° or 90° depending on the orientation of the joints with respect to the direction of the traffic.
Interlocking Concrete Pavement: A system of paving consisting of discrete, hand-sized paving units with either rectangular or dentated shapes manufactured from concrete. Either type of shape is placed in an interlocking pattern, compacted into coarse bedding sand, the joints filled with sand and compacted again to start interlock. The paving units and bedding sand are placed over an unbound or bound aggregate layer. Also called concrete block pavement.
Joint: The space between concrete paving units typically filled with sand.
Joint Filling Sand: Sand used to fill spaces between concrete pavers.
Joint Sand Gap: The vertical distance between the bottom of the chamfer on a paver and the top of the sand in the joint.
Laying Pattern: The sequence of placing pavers where the installed units create a repetitive geometry. Laying patterns may be selected for their visual or structural benefits.
Pavement Structure: A combination of subbase, base course, and surface course placed on a subgrade to support traffic loads and distribute it to the roadbed.
Permeable Interlocking Concrete Pavement: Concrete pavers with wide joints (l0 mm to 30 mm) or a pattern that creates openings in which rainfall and runoff can infiltrate. The openings are typically filled with aggregate and occasionally with topsoil and grass. The pavers are typically placed on an open-graded aggregate base which filters, stores, infiltrates, and/or drains runoff.
Plate Compactor: Also known as a plate vibrator, which is used to compact pavers into bedding sand in order to promote interlock among the individual units.
Screed Board or Strike Board: A rigid, straight piece of wood or metal used to level bedding sand to proper grade by pulling across guides or rails set on the base course or edge restraints.
Screed Guides or Bars: Grade strips such as pipe that will guide the screed in producing the desired elevation of the bedding sand.
Sealer: A material usually applied as a liquid that is used to waterproof, enhance color, and in some cases reduce abrasion of interlocking concrete pavements.
Soldier Course: A paver course where widths abut against the edge restraint.
Sub-base: The layer or layers of specified or selected material of designed thickness placed on a subgrade to support a base course. Aggregate sub-bases are typically made of stone pieces larger than that in bases.
Textured or Architectural Finish: Paver surfaces altered by the manufacturing mold or mechanical means, such as shot blasting, bush hammering, tumbling, grinding, polishing, flame treating, or washing. The purpose of such treatments is often to simulate the appearance of stone.