CALENDAR DAY: Any day shown on the calendar, and the 24-hour period thereof from
12:01 a.m. to midnight.
CANTILEVER: A beam which is securely supported at one end, and hangs freely at the other; an overhanging beam.
CAMBER: A slightly arched surface of a road to compensate for anticipated deflection or to allow for drainage.
CANTILEVER FOOTING: A combined footing that supports an exterior wall or exterior columns.
CAPILLARY PRESSURE OR SEEPAGE FORCE: In ground which is being drained from outside an excavation, capillary pressures help the excavated earth to stand steeply. However, if the ground is being drained from inside and not from outside the excavation, the capillary pressures will help the earth face to collapse.
CAPILLARY WATER: Water just above the water table which is drawn up out of an aquifer due to capillary action of the soil.
CARRIAGEWAY: The part of a highway which carrier vehicles.
CASSION: A cylindrical or rectangular rigged-wall for keeping water or soft ground from flowing into an excavation while digging for foundations or piles.
CAST-IN-PLACE or CAST-IN-SITU: Concrete deposited in its permanent place.
CAULKING: Using pressure gun for filling of a crack, crevice, seam or joint to make it air or water-tight.
CEMENT: A mixture of silicates and aluminates of calcium that when mixed with water it binds a stone-sand mixture into a strong concrete within a few days.
CEMENT MORTAR: Mortar usually composed of four parts sand to one of cement, with a suitable amount of water.
CENTER LINE OF HIGHWAY: A line equidistant from the edges of the median separating the main travelled ways on a divided highway, or the center line of the main traveled way on undivided highway.
CHANNEL: A natural or artificial water course.
CHAINAGE: A length (Usually 100 feet) measured by chain or steel tape.
CHANGE ORDER: A written order issued by the Engineer to the Contractor, and signed by both, which set forth any necessary or desirable changes in the contract including, but not limited to, extra work, increases or decreases in contract quantities, the basis of payment, contract time adjustments and other additions or alteration to the contract. A change order signed by the Contractor indicates his agreement therewith.
CHARACTERISTIC: A measurable property of a material, product or item of construction.
CHEVRON: V shaped strips meeting at an angle.
CHEZY-MANNING EQUATION: Used to measure water flow in open channels.
CHROMATING: Priming with lead or zinc to prevent forming of rust.
CLAY: Very fine-grained soil of colloid size (Finer than 0.002 mm), consisting mainly of hydrated silicate of aluminium. It is a plastic cohesive soil which shrinks on drying, expands on wetting, and gives up water when compressed.
COARSE AGGREGATE: (1) For concrete: aggregate which retained on the No. 4 sieve (4.76 mm). (2) For bituminous material: aggregate which retained on a sieve of 3 mm square opening.
COBBLE: Rock fragments between 3 to 6 in size.
COHESION OF SOIL: The stickiness of clay or silt. It is the shear strength of clay, which generally equals about half its unconfined compressive strength.
COHESIVE SOIL: A sticky soil like clay or clayey silt.
COHESIONLESS SOIL: Sand, gravel and similar soils, also known as frictional soils since their properties are defined more by their angle of internal friction than by cohesion.
COMPACTION: Artificial increase of the dry density of a granular soil by mechanical means such as rolling the surface layers, or driving sand piles for deep compaction, vibroflotation, or impact methods. There are many methods of compaction, six main types of compacting equipment are: (1) pneumatic-tyred rollers, in which the rear wheels cover the gaps left by the front wheels, (2) tamping rollers, (3) sheep-foot rollers, (4) vibrating rollers, (5) frog rammers (trench compactors), and (6) vibrating plates. The last two are used for confined spaces.
COMPOUND: A homogeneous substance composed of two or more elements that can be decomposed by chemical changes only.
CONCRETE: A mixture of water, sand, stone, and a binder (Usually Portland cement) which hardens to a stone like mass. There are four types of Portland cement:
- Type I: Normal Portland cement: This is general-purpose cement used whenever sulphate hazards are absent and when the heat of hydration will not produce objectionable rises in temperature. Typical uses are sidewalks, pavement, beams, columns and culverts.
- Type II: Modified Portland cement (Sulphate-resistant Portland cement): This type of cement is applicable when exposure to severe sulphate concentration is expected, generally used in hot weather in the construction of large concrete structures. Its heat rate and total heat generation are lower than for normal Portland cement.
- Type III: High-early strength Portland cement: This type develops its strength quickly. It is suitable for use when the structure must be put into early use or when long-term protection against cold temperatures is not feasible. Its shrinkage rate, however, is higher than for types I and II, and extensive cracking may result.
- Type IV: Low-heat Portland cement: For extensive concrete structures, such as gravity dams, low-heat cement is required to minimize the curing heat. The ultimate strength also develops more slowly than for the other types.
CONDUIT: Any open channel, pipe, etc., for flowing fluid. A pipe or tube in which smaller pipes, tubes, or electrical conductors are inserted or are to be inserted.
CONSISTENCY OF CONCRETE: Ease of flow or workability of concrete, measured by slump test or Kelly ball test.
CONSOLIDATION: The gradual, slow compression of a cohesive soil due to weight acting on it, which occurs as water, or water and air are driven out of the voids in the soil. Consolidation only occurs with clays or other soils of low permeability; it is not the same as compaction, which is a mechanical, immediate process and only occurs in soils with at least some sand.
CONTINUOUS BEAM: A beam extending over several spans in the same straight line.
CONTINUOUS or COMBINED FOOTING: A long footing supporting a continuous wall or two or more columns in a row.
CONTRACTOR: The person or persons, firm, partnership, corporation, or combination thereof, private or municipal, who have entered into a contract with the State (Client).
CONTRACT: The written agreement between the State (Client) and the contractor setting forth the obligation of the parties there under, including, but not limited to, the performance of the work, the furnishing of labor, equipments and materials and the basis of payment. The contract includes the Advertisement for Bids, Proposal, Bidding Schedule, Contract Agreement and Contract Bonds, Certificate of Insurance, Standard Specifications, Supplemental Specifications, Special Provisions, Project Plans, Standard Drawings and any Supplemental Agreements that are required to complete the construction of the work in an acceptable manner within a specified period, including authorized extensions thereof, all of which constitute one instrument.
CONTRACT PAYMENT BOND: The approved form of security, executed by the Contractor and his surety or sureties, guaranteeing complete performance of the contract and all supplemental agreements pertaining thereto and the payment of all legal debts pertaining to the construction of the project.
COPING: The cap or top course of a wall.
CORROSION: Disintegration or deterioration of metal, concrete or reinforcement by electrolysis or chemical attack.
CORRUGATIONS: Regular transverse undulation or alternate ridges upon a metal pipe surface to give greater rigidity to thin plates.
COURSE: The roadway horizontal pavement layer.
CRITERIA: The Client's requirements for the design and construction of a particular type of building, or structure.
CRITICAL: (1) Of, relating to, or being a turning point or specially important juncture. (2) Relating to or being a state in which a measurement or point at which some quality, property or phenomenon suffers a definite change.
CRACKING IN CONCRETE: Cracking is always expected in reinforced concrete, since it has such a high shrinkage on hardening. Additional cracks will occur on the stretched side of a beam. Reinforcement shall be inserted sufficient in quantity and closeness to make the cracks invisible to the naked eye and very close together. Contraction and expansion joints are constructed to reduce cracking.
CRACK: An open seam not necessarily extending through the body of a material. Some types of cracks in asphaltic or Portland cement concrete are:
- ALLIGATOR CRACK: A crack caused by fatigue of the asphaltic concrete surface layer or excessive movement of the underlying layers. Typically alligator cracks form an interconnected network of irregularly shaped polygons varying in size from a few square inches to 1 square foot.
- BLOCK CRACK: A crack caused by shrinkage of the bound surface material. Typically block cracks form an interconnected network of nearly square shapes varying in size from 1 square foot to several square feet.
- DURABILITY (D) CRACK: A series of closely-spaced cracks adjacent and roughly parallel to concrete pavement joints caused by the freezing and thawing of unsound aggregates that have high moisture content.
- RANDOM CRACK: A crack that is neither longitudinal nor transverse crack that has a little or no interconnection with other cracks. May be caused by movement, either of the pavement structure or sub-grade or both.
- REFLECTIVE CRACK: Crack in a pavement surface layer caused by the high stresses from movements of a cracked underlying layer.
- TRANSVERSE OR TEMPERATURE CRACK: A long crack approximately perpendicular to the centerline caused by longitudinal shortening of the bound surface layer, sometimes called temperature cracks as the shortening is often caused by contraction from temperature changes. Typically transverse cracks extend across the full width of the pavement.
- CRAZE CRACK: Numerous fine cracks which appear on the surface of concrete in a hexagonal or octagonal pattern. This type of crack is caused by improperly trowelled concrete surface.
CULVERT: A covered channel up to about 12 feet in width or a large pipe for carrying a watercourse below ground level, usually under a road or railway.
CURING: Keeping freshly poured concrete or mortar damp for specified time (Usually the first one week of its life) so that the cement is always provided with enough water to harden. This improves the final strength of concrete, particularly at the surface, and should reduce surface cracking or dusting.
DADO: Concrete barrier on the sides of bridge approach slab; the part of pedestal between cap and base.
DATUM: Any elevation taken as a reference point for levelling.
DECK: (1) A flat roof, a quay, jetty or bridge floor, generally a floor form with no roof over upon which concrete for a slab is placed. (2) Formwork for a level surface.
DEFORMED BAR: A reinforcing bar with ridges to increase bonding between the reinforcing bar and concrete.
DENSITY INDEX (relative density): is a measure of the tendency or ability to compact soil during loading. The density index is equal to 1 for a very dense soil; it is equal to 0 for a very loose soil.
DETOUR: A temporary route for traffic around a closed portion of a road.
DEVIATION: Difference between the value and the average of a set.
DIAPHRAGM: (1) A stiffening plate in a bridge between the main girders in a bridge or a stiffening web across a hollow building block. (2) Ligamentous wall separating two cavities.
DILUTION: Reducing a concentration of soluble material by adding pure water.
DISTILLATION: Salt removal process from brackish or sea water by boiling and condensation.
DITCH: Long narrow excavation for drainage, irrigation or burying underground pipelines.
DIVIDED HIGHWAY: A highway with separated traveled ways for traffic, generally in opposite directions.
DREDGE: To dig or excavate under water.
DUCT: A protective tube or a brick or concrete trench or corridor along which pipes or cables pass through the ground.
DUCTILITY: The ability of a metal to undergo cold plastic deformation without breaking, particularly by pulling in cold drawing.
DURABILITY: The ability of materials to resist weathering action, chemical attack, abrasion or other conditions of service.
DYKE: (1) A mound of earth along a river or channel bank to retain floodwater. (2) Large ditch. (3) A tabular-shaped igneous intrusion.