Civil Engineering Technical Terms and Meaning - For A & B

For ‘A’

ABRASION: The process of wearing away by friction.

ABUTMENT: A concrete support wall constructed at both ends of a bridge or an arch, in order to resist the horizontal force from the bridge or the arch, support the ends of the bridge span and to prevent the bank from sliding under.

ACCELERATOR: A substance such as calcium chloride (CaCl₂), added in small quantities (max. 0.03% of the cement) to plain concrete to hasten its hardening rate, its set or both.

ACQUISITION: The process of obtaining Right-of-Way.

ACTIVE EARTH PRESSURE: The horizontal push from earth onto a wall. The active earth force from sand on to a free retaining wall is equivalent to that from a fluid of density 0.25 to 0.30 times that of the sand. The force from sand on to a fixed retaining wall is very much more.

ADDENDUM OR ADDENDA: Written instruments or documents issued prior to the execution of a contract to modify or revise the bidding documents.

ADHESION OR BOND: The sticking together of structural parts by mechanical or chemical bonding using a cement or glue.

ADMIXTURE OR ADDITIVE: A substance other than aggregate, cement or water, added in small quantities to the concrete mix to alter its properties or those of the hard concrete. The most important admixtures for concrete are accelerators, air-entraining agents, plasticizers and retarders.

AFFIDAVIT OF NON-COLLUSION: A sworn statement, by bidders for the same work, that their proposal prices were arrived at independently without consultation or a secret agreement or cooperation for a fraudulent or deceitful purpose between or among them.

AGENT: The person who legally represents the contractor and acts for him on all occasions. He is often a Civil Engineer.

AIR-ENTRAINED CONCRETE: A concrete used for constructing roads. It has about 5% air and is therefore less dense than ordinary good concrete, but it has excellent freeze-thaw resistance. The strength loss is roughly 5% for each 1% air entrained. Air entrained concrete produced by adding an admixture to concrete or cement, which drags small bubbles of air (Smaller than 1 mm in diameter) into the concrete mix. The bubbles increase the workability and allowing both sand and water contents to be reduced.

ALIGNMENT: (1) The fixing of points on the ground in the correct lines for setting out a road, railway, wall, transmission line, canal, etc. (2) A ground plan showing a route, as opposed to a profile or section, which shows levels and elevations.

APPURTENANCE: An item which belong with, or is designed to complement something else (For example, a manhole is a sewer appurtenance.)

APRON: A floor constructed along the channel bottom to prevent scour. Aprons are almost always extension of culverts.

AQUIFER: An underground source of water capable of supplying a well.

ARITHMETIC MEAN: The average value which is defined as the sum of all of the observations divided by the number of observations.

ARTESION WELL: A spring which water flows naturally out of the earth's surface due to pressure placed on the water by an impervious overburden and hydro-static head.

ARTERIAL HIGHWAY: A general term denoting a highway primarily for through traffic usually on a continuous route.

AS-BUILT DRAWINGS OR RECORD DRAWINGS: Construction drawings revised to show significant changes made during the construction process, usually based on marked-up prints, drawings and other data furnished by the contractor or the Engineer.

ASPHALTIC CONCRETE FRICTION COURSE (ACFC): A hot mixture of asphalt cement with an open-graded aggregate (20% to 25% air voids) of a maximum size of 3/8 inch used as a surface (Wearing) course.

ASPHALT RUBBER (AR): A mixture of asphalt cement and rubber used as a crack sealant, binder, or membrane.

ASPHALTIC CONCRETE (ASPHALT RUBBER): A hot mixture of asphalt cement, rubber, fine and coarse aggregate and mineral admixture mixed together and placed as an asphaltic concrete pavement surface layer. The advantages of this mix are: It stops cracks from reflecting through pavement layers, reduce the riding tires noise and is a useful way to dispose of the used rubber tires.

AUXILIARY LANE: The portion of a roadway adjoining the travelled way for truck climbing, speed change or for other purposes supplementary to through traffic movement.

For ‘B’

BALLAST: Coarse stone or hard clinker, sand or slag carried by a moving unit to keep it held down or to keep equilibrium steady.

BANK: A mass of soil rising above a digging level.

BASE COURSE: One or more layers of specified materials of designed thickness (Usually asphaltic concrete course), placed on a sub-base course or a sub-grade to support a surface course.

BASEMENT MATERIAL: The material in excavation or embankment underlying the lowest layer of sub-base, base, pavement, surfacing or other specified layer which is to be placed on.

BASIN: A receptacle for runoff (Storm) water.

BATTER: Inward slope from bottom to top of a wall face.

BERM: An artificial horizontal ledge in an earth bank or cutting to ensure the stability of a steep side slope of roadbed (Shoulder). Also berms are built to hold water on land that is to be flood irrigated.

BEAM: A horizontal structural member designed to resist loads which bend it.

BEARING: (1) The supporting section of a beam length or area. (2) The compressive stress between a beam and its support (bearing pressure), particularly on foundations. (3) The horizontal angle turned between a datum direction such as true north and a given line.

BENCH MARK: A relatively fixed point whose elevation is known and used as a datum for levelling.

BENDING FORMULA: Formula for beams of any homogeneous material.

Moment (M) = Stress × Modulus of Section or (M) = Force × Arm

BIDDER: Any individual, firm, partnership, corporation, or combination thereof, submitting a proposal for the work contemplated, acting directly or through a duly authorized representative.

BINDER: (1) A material such as cement, tar, bitumen, gypsum plaster, lime, or similar material, when mixed with other material, it causes uniformity, consistency, solidification or cohesion. (2) The clay or silt in hoggin or the cement rock. (3) A stirrup or steel rod usually about 6 to 10 mm diameter used for holding together the main steel in a reinforced-concrete beam or column.

BITUMINOUS SEAL COAT: A thin bituminous application to a surface or wearing course to seal and waterproof small voids and to embed sand or chips to provide better traction.

BLEEDING or FLUSHING: (1) Separation of clear water from the cement paste of mortar or concrete. Two types are known, the first beneficial, the second harmful to concrete strength, but they may co-exist. The first occurs during compaction, water can flow out of concrete, lie on its surface, and thus encourage good curing for the first few hours during hot weather. The second type of bleeding occurs after compaction, water segregates beside or under the steel or larger stones, weakening the bond between them and the body of the concrete. A plasticizer should enable the water to cement ratio to be lowered to reduce this type of bleeding. (2) Upward migration of bituminous material resulting in a film of asphalt on the surface.

BLEMISH: Any imperfection which mars the appearance of wood, concrete, paint or other finished surface.

BLINDING: Mat or mattress or sealing coat. A layer of lean concrete usually 2 to 4 inches thick, put down on soil such as clay to seal it and provide a clean bed for reinforcement to be laid on.

BLOTTER: Absorbent material (e.g., sand) to dry freshly wet surfaces.

BORING: A drilling into the earth to bring up samples of the soil.

BORROW: Suitable material excavated from sources outside the roadway prism (e.g., Borrow Pit), to provide fill elsewhere, primarily for embankment.

BOULDER: A rock which is too heavy to be lifted readily by hand.

BOULEVARD: A wide city street usually planted with shade-trees (Landscaped).

BRIDGE: A single or multiple span structures, including supports, erected over a depression or an obstruction such as water, a highway or railway and having a track or passageway for carrying traffic.

BRIDGE BEARING: The support at the bridge pier or abutment, which carries the weight of a bridge.

BRIDGE DECK: The load-bearing floor of a bridge, that carries and spreads the loads to the main beams.

BRIDGE LENGTH: The greater dimension of a structure measured along the center of the roadway between backs of abutment back-walls or between ends of the bridge floor.

BRIDGE ROADWAY WIDTH: The clear width of structure measured at right angles to the center of the roadway between the bottom of curbs or between the inner faces of parapet or railing.

BYPASS: Road joining two parts of an older road to avoid a town or village.