AASHTO: American Association of State Highway and Transportation Officials
Absorption: The penetration of liquid into aggregate particles with an increase in particle weight.
Acid-Soluble Material: Material that is soluble in 4 mol/L Hydrochloric Acid, contained in fine aggregate.
Acrobatch An oscillating mechanical aggregate feeder usually used for feeding dry aggregates from storage bins.
Activity (A) of a soil is the PI divided by the percent of clay-sized particles present. Different types of clays have different specific surface areas which controls how much wetting is required to move a soil from one phase to another such as across the Liquid Limit or the Plastic Limit. From the activity one can predict the dominant clay type present in a soil sample. High activity signifies large volume change when wetted and large shrinkage when dried. Soils with high activity are very reactive chemically. Normally, activity of clays is from the range 0.75 – 1.25 and it is assumed that the plasticity index is approximately equal to the clay fraction (A = 1). – A < 0,75 – inactive soil – A > 1,25 – active soils
Adhesion Agent A substance used for the purpose of improving the adhesion between a bituminous binder and the aggregate.
AggregateSand, gravel, crushed stone and quarried rock used for construction purposes.
Aggregate Abrasion Value (AAV) Specimens of chippings passing 14mm and retained on the 20mm-14mm flake-sorting sieve, are held in resin and subjected to wear on a standard flat circular metal surface fed with high silica sand. Percentage loss in weight gives the AAV. Results range from 1 (some flints) to 15 (normally regarded as too soft for use in wearing course) LOW RESULTS BEST.
Aggregate Crushing Value (ACV)14mm – 10mm chippings subjected to 400 Kn. Loads evenly over 10 minutes. Sieved on 2.36mm sieve. Percentage passing gives ACV. Results range 10 (very strong) to 35 (normally regarded as too weak for use in road surfacing). LOW RESULTS BEST.
Aggregate Gradation The distribution of aggregate particles among various sizes, usually expressed in terms of cumulative percentages larger or smaller than each of a series of sizes (sieve openings) or the percentages between certain ranges of sizes (sieve openings).
Aggregate Impact Value (AIV) As for ACV but subjected to 15 blows impact using standard apparatus. Similar results to ACV except for brittle rocks, e.g. Quartzite and hard grit stones, which can be up to 3 points higher. LOW RESULT BEST.
Aggregate Testing Any of a number of tests performed to determine the physical and chemical characteristics of an aggregate. Common tests are for abrasion, absorption, specific gravity, and soundness.
Agricultural Dust Sedimentary rock consisting largely of calcium carbonate and containing not more than 15% magnesium expressed as MgO and of which 100% will pass through a 5mm sieve, not less than 95% will pass through a 3.35mm and not less than 20% will pass through a 150 micron sieve.
Alkali-Carbonate Reaction The reaction between the alkalis (sodium and potassium) in portland cement binder and certain carbonate rocks, particularly calcite, dolomite and dolomitic limestone’s, present in some aggregates; the products of the reaction may cause abnormal expansion and cracking of concrete in service.
Alkali-Silica Reaction The reaction between the alkalis (sodium and potassium) in portland cement binder and certain siliceous rocks or minerals (e.g. opaline chert, strained quartz, acidic volcanic glass) present in some aggregates; the reaction particularly takes place in warm, moist climates or environments and the products of the reaction may cause abnormal expansion and cracking of concrete in service.
All-In Aggregate Aggregate consisting of a mixture of coarse and fine aggregates. It may be produced without separating into coarse and fine fractions, or by combining coarse and fine aggregate (sand).
Ambient water quality Water in its natural state; the existing environmental condition of the water or how it was found.
Angular Aggregate Aggregate particles that possess well-defined edges formed at the intersection of roughly planar faces.
Aquifer A layer of gravel, sand or porous, fractured rock containing saturated permeable material through which significant amounts of ground water can travel to wells and springs.
AREA American Railway Engineering Association
Armor stone 2 to 8 ton boulders used to construct jetties to prevent erosion due to the action of large waves.
Armour Stone Large pieces of rock between 1 ton and 15 ton for sea defense or river defense.
Artificial Aggregate Aggregate of mineral origin resulting from an industrial process involving thermal or other modification.
As-built drawings Engineering plans that have been revised to reflect all changes to the plans that occurred during construction.
As-graded The configuration of the surface conditions on completion of grading.
Asphalt A black petroleum residue, which can be anywhere from solid to semisolid at room temperature. When heated to the temperature of boiling water, it becomes able to be poured. It is used in surfacing roads (mixture of bitumen and aggregate), roofing materials, in lining the walls of water-retaining structures such as reservoirs and swimming pools, and in the manufacture of floor tiles.
asphaltic concrete A mixture of coarse aggregate, fine aggregate, liquid asphalt and possibly other additives that when mixed in a Hot Plant and properly placed and compacted at the jobsite, provide a hard and durable flexible pavement.
ASTM American Society for Testing and Materials
Atterberg Limits Basic measure of the nature of a fine-grained soil. Depending on the water content of the soil, it may appear in four states: solid, semi-solid, plastic and liquid. In each state the consistency and behavior of a soil is different and thus so are its engineering properties. Thus, the boundary between each state can be defined based on a change in the soil’s behavior. It was then done by A. Atterberg in terms of limits: Liquid Limit (LL) – the boundary between the liquid and the plastic states; Plastic Limit (PL) – the boundary between the plastic and the semi-solid states; Shrinkage Limit (SL) – the boundary between the semi-solid and the solid states.
Average Least Dimension (ALD) The average height of the aggregate particles when they are spread as a single layer with their least dimensions vertical.
Average monthly discharge The average of the measured turbidity or other water quality values (TSS, TDS, etc.) collected from a discharge point over a calendar month’s time. For further water quality information related to the environment, contact the local office of the Ministry of Water, Land and Air Protection. For information related to discharge and drinking water, contact the local office of the Regional Health Authority.
Backhaul Material delivered back to a pit or quarry location. Material could be crushable or non-crushable, depending upon parameters set at the individual dump location.
Baffles Partitions within a settling pond or retention basin designed to increase the length the water travels before discharge.
Ballast The mix of coarse and fine aggregates.
Basalt A fine-grained basic volcanic rock, which can be used in aggregate production, similar in composition to gabbros.
Baserock Aggregate Base is a well-graded aggregate suitable for compacting to such a degree that it provides a firm, stable base. Project specifications determine what class of aggregate base will be used.
Batch Mixer A type of coating plant where a pre-set amount of aggregate and bitumen are mixed at one time.
Bedding Aggregate onto which slabs, blocks or pipes are laid. Usually single size for pipes and coarse sand or coarse dust for blocks and slabs.
Bedrock The solid rock that underlies the soil, overburden and unconsolidated material.
Belt Weigher Equipment fixed to a conveyer that weighs the material carried on the conveyer.
Bench A relatively level or back sloping step, excavated or constructed on the face of a graded slope surface for safety, stability, drainage and to facilitate maintenance.
Berm A constructed barrier of overburden, topsoil or waste rock, often planted with trees, shrubs and ground cover. Berms are used to block noise, dust and views of an aggregate operation from reaching adjacent properties.
Best management practices (BMP) BMPs can be physical structures, activities, practices or procedures that prevent, reduce or mitigate an undesired event, impact or effect.
Bin A large container of processed aggregate holding anything from 1 ton to 60 ton.
Binder An adhesive used to hold aggregate together in a coherent mass or, as in a surface dressing, to stick chippings to a road surface or to coat chippings used in surface dressing or scattered on the surface of a wearing course.
Biodiversity The variety and variability among living organisms and the ecological complexes in which they occur.
Bioengineering Restoration or reinforcement of slopes and stream banks with living plant materials.
Biophysics The study of the biological and physical characteristics of an area (e.g., topography, soils, climate, landforms, watercourses, vegetation, etc.).
Bit’ Sand A mixture of natural sand and bitumen, used mainly for the bases of large steel storage tanks.
Bitumen A product of the oil refinery process that is usually stored at approximately 150°C to maintain it in a liquid form. Used in asphalt and spray seal applications.
Blast The breaking up of the quarry face with the use of explosives.
Bond The adhesion of cement paste to aggregate and or the rebar.
Borrow pit An excavation to provide fill for construction activities.
Boulder Pieces of rock larger than 200mm
Bound Material A mixture of fine and coarse aggregates bound together with bitumen, cement etc.
Buffer strip A strip of land that separates incompatible activities. Buffer strips can be used to intercept dust and noise, enhance aesthetics or other qualities along or adjacent to residences, roads and trails, filter storm water runoff or protect an environmentally sensitive area such as a stream (riparian area). They may be land left in its natural state or planted to perform specific objectives.
Building Sand A naturally occurring sand which can be used for mortar for laying bricks or wall rendering.
Bulk Density The volume occupied by an aggregate. Either loose, where the aggregate is placed into a cylinder of a known volume and weighed, or compacted, where the aggregate is placed into the same cylinder and tamped down in layers and then weighed (expressed in kg/m3).
Cement-Aggregate Ratio The ratio, by weight or volume, of cement to aggregate in concrete.
Chipseal An application of a clean sized-aggregate which is applied to a freshly spread layer of asphalt emulsion
Clay Grains of rock less than 0.002mm.
Clean Stone Description of single size aggregates used for sizes from 3mm to 150mm.
cleanness value An indication of the clay-sized material clinging to coarse aggregate
Clearing The removal of trees and shrubs.
Coarse aggregate Generally considered to be aggregate that is larger than the #4.
Coated Macadam Graded aggregate that has been coated with bituminous binder and in which a major part of the strength of the mixture is derived from interlocking of the aggregate.
Cobble Pieces of rock between 60mm and 200mm
coir fascines Although “coir” is actually made from coconut husks, this term has been adopted in BC to mean a mat or bundle made from willow whips, branches or cuttings for such uses as filling ditches or making revetments on unstable slopes or banks.
Cold Bin/Feeder A small ground hopper into which aggregates are put to be fed into a coating plant. At the base of the bin is a feeder, which is sometimes calibrated to deliver accurate quantities of stone.
Combined Aggregate Grading Particle size distribution of a mixture of fine and coarse aggregate.
Community values Consensus, expectations and opinions of a local population.
Competency A measure of the strength or soundness of rock.
Concrete A composite material that consists essentially of a binding medium in which is embedded particles or fragments of relatively inert material filler. In portland cement concrete, the binder is a mixture of portland cement and water; the filler may be any of a wide variety of natural or artificial aggregates.
Concrete Aggregates Aggregates that are used in the production of concrete products and ready-mix concrete.
Cone Crusher A type of crusher that crushes the stone by pressure in a squeezing action. Basically a cone shape gyrates eccentrically round a fixed constraint against which the stone is crushed.
Conveyer Thick rubber belting of various widths, depending on capacity required, for the movement of aggregates from one part of a process to another.
Crushed aggregates Any hard, sound rock that is produced by blasting and then crushing. The aggregate is then screened to a specific size.
Crushed Gravel The product resulting from the artificial crushing of gravel.
Crushed stone Rock, boulders and cobbles that are blasted or mined and subsequently crushed and processed into aggregate.
Crusher-run Aggregate Aggregate that has been broken in a mechanical crusher and has not been subjected to any subsequent screening process.
Degradation The breakdown into smaller pieces of an aggregate when subjected to applied forces such as those produces by mixer blades, compaction, heavy wheeled loads, and grinding action.
Deleterious Harmful to health or well-being.
Deleterious materials Those substances present in an aggregate that are harmful to the desired properties of an aggregate-binder system.
Dense Bitumen Macadam Bitumen macadam in which the aggregates and filler are so graded as to form a close textured mixture, of low permeability, when spread and compacted.
Dense Graded Mix An asphalt produced with aggregate that produces a continual grading. Usually low air voids as compared with open graded products.
Dense-graded Aggregate Aggregates graded to produce low void content and maximum weight when compacted.
Density The measure of weight of the aggregate per cubic meter.
Deposit characteristics Physical properties, sedimentary features, quality, particle gradation and composition of a deposit.
deposit model A planning model that includes the geological feature that makes up the sand and gravel (e.g., Delta, alluvial terrace, outwash plain, drumlin), the deposit characteristic (e.g., rock types, rock characteristics), the deposit size (e.g., surface area, depth) and environmental effects of mining (e.g., high clay content).
Deposit size Surface area, thickness and volume of gravel.
Dimension Stone Stone quarried from the ground in large blocks then cut, shaped and carve to specific patterns.
Ditch grade control The action of controlling the steepness of a channel, ditch or any watercourse. Grades of less than 5 percent are generally desirable for watercourses to avoid erosion. Check Dams are commonly used to control grades in ditches.
Dolomite A mineral having a specific crystal structure and consisting of calcium carbonate and magnesium carbonate in equivalent chemical amounts (54.27 and 45.73 percent by weight, respectively); a rock containing dolomite as the principal constituent.
Drain rock A clean durable aggregate that when in place allows the flow of water.
drainage blanket A layer of aggregate that allows the passage of water
Drill Rig The plant used for drilling the holes for blasting.
Drilling The means of producing holes for charging with explosives to blast rock from the quarry face.
Drum Mix A coating plant that dries the aggregate, adds the bitumen, and mixes the materials all within a long rotating drum.
Dryer The rotating drum part of a batch mixing plant in which the aggregate is dried.
Drying Shrinkage Aggregates under test are made into concrete prisms that are carefully measured and then subjected to a cycle of wetting and drying. Any change in length is the drying or shrinkage. LOW RESULTS BEST.
Durability The resistance of aggregate particles to the accumulative effects of environmental and cyclical load conditions. Lack of aggregate durability results leads to a breakdown of aggregate particles resulting in an alteration in gradation and impairment of performance.
Dust A commonly used term for fine hard rock quarried aggregates. After all single sizes have been screened off down to 6mm the remaining material-passing 6.3mm is dust. Sometimes this can be screened again to produce a fine dust and 3mm single size.
Effluent Waste material released either into the air or water, or onto land.
Egress 1) the act or an instance of going, esp. from an enclosed place. 2) A means or place of going out; an exit. 3). the right or permission to go out.
Elongation If an aggregate has one dimension substantially greater than the other two, it then suffers from elongation.
End Result Specifications The type of specifications written to focus on finished product compliance with project specifications.
erosion The wearing away of the ground surface as the result of wind, running water, ice or other geological agents, including such processes as gravitational creep.
Erosion and sediment control Procedures intended to prevent erosion and sedimentation, such as preserving natural vegetation, seeding, mulching and matting, plastic covering, filter fences, and sediment traps and ponds.
Exposed Aggregate Surface texture where cement paste is washed away from concrete slab surface to expose durable chip-size aggregates for the riding surface.
Extraction The process of removing raw material, rock or aggregate from the deposit location.
Face The exposed unbroken rock of the quarry after a blast has taken place.
Feed The flow of aggregate into a crusher, screen house or coating plant.
Filler A fine mineral powder substantially passing the 75um sieve. Derived from the dust suppression on crushing, screening, coating plants etc or by fine grinding of aggregate other similar granular material.
Filter fabricFabric used to prevent the migration of fines from one layer to another.
Filter Layer The layer of fabric, sand, gravel, and/or graded rock placed between a bank revetment and soil for the purpose of prevent the soil erosion through the bank revetment while allowing natural subsurface seepage through the bank;
Fine aggregateGenerally considered to be any material that passed the 3⁄8″ sieve, and essentially all passes the #4 sieve and is predominantly retained on the #200 sieve.
Fineness Modulus An index of fineness or coarseness of an aggregate sample. An empirical factor determined by adding total percentages of an aggregate sample retained on each of a specified series of sieves, and dividing the sum by 100.
Fines A BS882 description referring to solid material passing a 75-micron sieve. Sometimes used as a common descriptive term for fine aggregate (sand).
Flake Aggregate pieces that have two dimensions substantially larger than the third.
Flakiness Index The calculated index of the amount of flake in each individual size, which has been combined to produce a graded material.
Flocculation The process by which suspended or very fine particles in water are assembled into larger masses or floccules that eventually settle out of suspension. This process occurs naturally, but can also be accelerated through the use of chemicals such as alum.
Fog seal A very light application of diluted asphaltic emulsion, generally applied without an aggregate cover, to enrich and seal the surface of a bituminous pavement.
Fretting Loss of particles of aggregate from a wearing surface associated with deteriorating adhesion or cohesion in a material.
Fugitive dust Dust which is generated by unstable, non-point sources like movement of equipment and the effects of wind and rain on stockpiles and areas stripped of vegetation. Fugitive dust is the most common cause of dust complaints at aggregate operations, as it commonly settles on cars and in homes.
Gabion 3″ to 10″ stone used to fill galvanized a woven steel wire basket that is used for erosion control and retaining wall construction.
Gap-graded Aggregate Aggregate so graded that certain intermediate sizes are substantially absent.
Gas sand Utility sand approved, or pending Agency approval by the Gas Company for use in and around gas lines. Cannot have many fractured faces (sharp edges to possibly puncture gas lines)
Grab sample A single sample or measurement taken at a specific time or over as short a period as is feasible.
Gradation The distribution of different particles of aggregate by size.
Grade The elevation of the ground surface. Existing grade is the grade prior to disturbance. Rough grade is the stage at which the grade approximates the final finished grade. Finish grade is the final grade of the site Grading is any excavating, filling, removing or placement of material, or combination thereof.
Grading Aggregate The quantities of the various particle sizes present in a mineral aggregate, expressed as a percentage by mass of the whole. Also referred to as particle size distribution.
Granules A commonly used description of aggregate smaller than 3mm.
Gravel A non-coherent natural, detrital, mineral aggregate from natural disintegration of rock, consisting mainly of rounded pebbles for sub-angular rock fragments, or both. Usually occurs as part of a “sand & gravel” deposit. Fragment size between 2mm and 60mm.Unconsolidated materials that are made up of rock fragments 2 mm to 75 mm in diameter
Grit Small size aggregate, 5mm or less.
Ground water Water that passes through or stands underground in porous rocks and soils, in the zone of saturation, that is under a pressure equal to or greater than atmospheric pressure and supplies wells. The Ministry of Water, Land and Air Protection is responsible for regulating groundwater quality.
Grubbing The removal of stumps and root systems from the soil.
Hardstone Exceptionally durable stone such as granite which is used in the top surface of roads to improve skid resistance and prevents rutting.
Heavy-Weight Aggregate An aggregate of very high unit weight, such as barium, boron, or iron ore, steel shot or punchings, which forms a high density mortar of concrete when bound together with hardened cement paste.
Hoggin A naturally occurring mixture of sand and gravel – containing sufficient clay to hold the mixture together when compacted. It is often in the form of overburden on top of good quality sand and gravel. Much used as base material in minor roads, foundations etc. on private housing developments.
Honeycomb An area in a foundation wall where the aggregate (gravel) is visible. Honeycombs can be usually be remedied by applying a thin layer of grout or other cement product over the affected area.
Hot Rolled Asphalt A road material consisting of a dense mixture of mineral matter and bituminous binder in which the mortar of fine aggregate, filler and high viscosity binder is a major factor in the performance of the compacted wearing course, base course or road base. As the strength of asphalt is derived from the stiff mortar (binder/sand/filler) the aggregate type is of little importance. In wearing course asphalt (normally 30% stone content) the greater part of the mix is sand (53%). It can be used at all layers in the road construction, i.e. road base, base course, wearing course. Normally 60% stone content is used for road base and base course and a 30% stone content for wearing course. Much asphalt wearing course now has designed binder content and has to meet a stability (strength) requirement dependent on the traffic density in terms of commercial vehicles. Such a requirement often necessitates the use of blended sand/crushed rock fine aggregate. Rock fines are also permitted by BS594. Because asphalt uses a high percentage of stiff bitumen it is expensive to produce (bitumen cost and aggregate heating costs). In consequence it is only used on heavily trafficked trunk roads and motorways where its cost can be justified. Normally produced on a semi-continuous or “asphalt” plant. Coated chippings are usually embedded into the surface of low coarse aggregate content hot asphalt to improve the surface texture and skid resistance. In consequence the chippings used should be of a high PSV and low abrasion value with good shape and size (normally 20mm size).
Hydroseeding A process whereby seed, fertilizer, wood fiber mulch and/or other agriculture approved additives are mixed together to form a slurry that, when applied to soil, encourages vegetation growth and is an effective means of erosion control.
Impact Crusher Type of crusher in which the breaking process is by impact action, since the rock is not crushed but rather fragmented by kinetic energy imported into the feed system.
Ingress 1) the act of going in or entering. 2) The right to enter. 3) A means or place of entering; entryway.
Interlock The characteristic of a crushed angular aggregate to key into adjacent angular aggregates that provides superior strength and load-carrying capabilities.
Jaw Crusher The crushing action resulting from the simple reciprocating motion takes place only during the forward stroke of the swinging jaw i.e. during half the time of operation of the crusher. The stone is crushed by pressure in a squeezing action.
Lake Asphalt A naturally occurring mixture of bitumen and finely divided mineral matter which is found in well-defined surface deposits.
Leachate Water or other liquid that has percolated through raw material, product, or waste and contains substances in solution or suspension as a result of the contact with these materials.
LI (see liquidity index)
Lightweight Aggregate Aggregate of low density, such as (a) expanded or sintered clay, shale, slate, diatomaceous shale, perlite, vermiculite, or slag; (b) natural pumice, scoria, volcanic cinders, tuff, and diatomite; (c) sintered fly ash or industrial cinders, used to produce lightweight concrete.
Limestone A sedimentary rock, consisting predominantly of calcium carbonate.
Liquid limit The water content at which the minus #40 size fraction passes from a plastic to a liquid state.
Liquidity index (LI) is used for scaling the natural water content of a soil sample to the limits. It can be calculated as a ratio of difference between natural water content and plastic limit, and plasticity index.
Lithology The physical character and composition of a sediment or rock, generally defined by its mineral composition.
Loadout facility Site and equipment for loading gravel into trucks or rail cars, or onto barges.
Lock Down Seal A reseal to prevent further loss of aggregate if original seal is experiencing aggregate loss. Normally 5mm or 7mm aggregate applied. Also referred to as Pin Down Seal.
Macadam Refers to a pavement type generally consisting of large single size aggregate with a surface layer of smaller material with or without binder to lock the surface together. Can be either a bitumen based or water based Macadam Pavement.
Macro texture Description of the road surface produced by different sizes or types of aggregate.
Magnesium Sulphate Soundness This test method is for determining the soundness of aggregates by subjecting the aggregate to cycles of immersion in a saturated solution of magnesium sulphate followed by oven drying.
Magnetite An aggregate used in heavy weight concrete, consisting primarily of ferrous metaferrite (Fe304). A black magnetic iron ore with specific gravity of approximately 5.2 and a Mohs hardness of about 6.
Matrix This is the internal physical components of a coated or dry stone material.
Maximum daily discharge limitation The highest allowable daily discharge of a pollutant, such as turbidity, measured during a calendar day or any 24-hour period that reasonably represents the calendar day for purposes of sampling. The daily discharge is calculated as the average measurement of the pollutant over the day.
Maximum particle size The minimum size screen opening through which 100% of the material will pass.
Maximum Size Aggregate Aggregate whose largest particle size is present in sufficient quantity to affect the physical properties of concrete; generally designated by the sieve size on which the maximum amount permitted to be retained is 5 or 10 percent by weight.
Mesh The number of openings (including fractions thereof) per unit of length in either a screen or sieve in which the openings are 6 mm or less.
Methylene Chloride Non-inflammable, volatile solvent used for washing bitumen from coated materials. A very good organic solvent not soluble in water. The solvent used for washing bitumen from coated material so the aggregate can be graded and bitumen content calculated.
Micron A micron is one thousandth of a millimeter.
Microsilica A fine powder additive to fresh concrete giving great increases in initial strengths and resistance to abrasion. Microsilica mixes allow use of a structure considerably faster than usual, giving a typical 30N/mm2 strength in a matter of 36-48 hours rather than the usual 28 days. Ideal for use in harsh environments such as coastal protection.
Microtexture This is the description of the actual surface of exposed aggregate on the road surface.
Mineral Reserves Geological deposits which are subject to planning permissions for extraction.
Mineral resource conservation The act of reserving the opportunity to extract mineral resources.
Mineral Resources Geological deposits, similar to those forming reserves, where economically workable minerals may prove to be present but remain as areas without planning permission.
Mining face The exposed vertical or near vertical portion of soil or rock that results from mining activity. Shape is generally determined by the reach of loading equipment working on the face.
Mobile Plant Equipment within the quarry which can be moved about, e.g. Loading Shovels, Compressors, Dumpers and Drill Rigs.
Mortar A mix of sand, cement and water which is used to bind together bricks and building stones.
MSHA Mine Safety & Health Administration (Federal)
Natural Aggregate Aggregate from mineral resources which has been subjected to nothing more than mechanical processing.
Natural Sand Sand resulting from natural disintegration and abrasion of rock.
Nominal Maximum Size Aggregate The smallest sieve opening through which the entire amount of the aggregate is permitted to pass; sometimes referred to as “maximum size” (of aggregate).
Normal Weight Aggregate Aggregate of mineral origin having a particle density not less than 2000 kg/m3.
Nuclear Density Meter An instrument for the non-destructive determination of the density and moisture content of material using a radioactive source for its operation.
Oarticle shape The shape of the individual aggregate particle.
Oven Dry Density Aggregate is dried in an oven then weighed. This weight is then used to calculate the density.
Overburden Rock, soil, or loose debris that is above the mineable aggregate resource and is of insufficient quality to process into construction grade aggregate.
Overfall The height above a surface watercourse from which a drainage structure discharges.
Particle Size The effective diameter of a particle measured by sedimentation, sieving, or micrometric methods.
particle strengthThe magnitude of tensile and/or compressive stress that an individual aggregate particle can withstand before failure occurs
Particle surface texture The degree of roughness or irregularity of the surface of an aggregate particle.
Particle-size Distribution Particle distribution of granular materials among various sizes, for aggregates normally designated as gradation. It is usually expressed in terms of cumulative percentages smaller or larger than each of a series of sieve openings or percentages between certain ranges of sieve openings.
Paving fabric A fabric used on an asphalt pavement overlay that when properly installed will prevent the cracks present in the original asphalt layer from transferring to the new pavement section.
Pea Beach A commonly used term for 20mm single size gravel, particularly from marine sources where material is naturally more rounded.
Pea Gravel A commonly used term for 10mm or 20mm single size gravels, particularly from marine sources where material is naturally more rounded.
pea gravel A clean rounded aggregate usually ¼” or 3⁄8″ typically used in drainage applications or in PCC
Pea Shingle A commonly used term for 10mm single size gravel, particularly from marine sources where material is naturally more rounded.
Pecker Hydraulic ram, which is used to break large pieces of rock down to a size, which can be crushed.
Percent Fines Amount, expressed as a percentage, of material in aggregate finer than a given sieve, usually the No. 200 (75 mm) sieve; also, the amount of fine aggregate in a concrete mixture expressed as a percent by absolute volume of the total amount of aggregate.
Perched water table Ground water trapped above an impervious layer of material such as a clay bed.
Permeability This is the ability of a material to let water pass through it and drain away.
Permeable Subbase Layer consisting of crushed aggregates with a reduced amount of fines to promote drainage and stabilized with Portland cement or bituminous cement.
Petrographic A procedure to determine the composition of coarse and fine aggregate in geological terms.
pH The pH of a substance measures its acidity or alkalinity in a scale that ranges from 1 to 14. A ph of 7 is defined as neutral, and large deviations, either above or below this value, are considered harmful to most aquatic life.
PI (see plasticity index)
Pipe Bedding Aggregate used for laying pipes into a trench to provide equal support along their length. Different sizes are used for different sized pipes.
Pit An open shallow surface working, from which sand and gravel is excavated from its natural bed.
Pit Run Unscreened alluvial aggregates as extracted from a pit.
Pitting The disintegration of weak, friable pieces of aggregate due to frost action.
Plant Mix A mixture of aggregate and asphalt cement or liquid asphalt, prepared in a central or traveling mechanical mixer.
plastic limit The lowest water content at which the minus #40 fraction remains cohesive enough to hold together when rolled with the fingers on a glass plate or sheet of unglazed paper into a thread 1⁄8″ in diameter.
Plasticity, Plastic Index This is a measure of the amount of clay in a drystone material. The plastic index is a ratio of the Plastic Limit and the Liquid Limit. Soils with a high PI tend to be predominantly clay, those with a lower PI tend to be predominantly silt, and those with a PI of 0 tend to have little or no silt or clay.
Polished Aggregate Friction Value (PAFV) A measure, on a scale of 0 to 100, of the resistance of an aggregate to polishing under the action of traffic as determined in standard laboratory tests.
Polished Stone Value (PSV) A measure of an aggregate’s resistance to the polishing action of vehicle tires. (Limestone – 40/45, Granite – 50/65, Gritstone – 55/70+).
pollutant An inorganic or organic substance or sound in the environment that, because of its chemical composition or quantity, prevents the functioning of natural processes and produces undesirable environmental and health effects or adversely affects the usefulness of a resource. With respect to water, pollutants include any man-made or man-induced alteration of the physical, biological or chemical integrity of the water.
Pollution Contamination of the environment with objectionable or offensive matter.
Porosity The percentage of open spaces between pieces of gravel cobble etc.
Portland Cement Concrete A mixture of hydraulic cement, coarse aggregate, fine aggregate, water, and possibly admixtures when properly mixed and allowed to properly hydrate provide a strong, hard structural building material.
Pre-Coated Chippings Normally 20mm or 14mm high PSV aggregate with 1.5% 50 Pen coating of bitumen, which is then allowed to cool, then broken up so they can be spread onto asphalt and rolled in when the material is hot. It provides the skid resistance and texture depth.
Precoating The coating of aggregate with a liquid to improve adhesion with the bituminous binder and the aggregate.
Pre-placed aggregate Coarse aggregate placed in a form, with Portland cement grout injected later.
Pressure Filter Apparatus used to force the methylene chloride bitumen liquor from the aggregate filler through a filter paper under pressure.
Primary Crusher The first crushing process after material has been won from the ground.
Primer Seal An application of a primer binder with a fine cover aggregate to a prepared base to provide penetration of the surface and retain a light cover of aggregate. It is used as a preliminary treatment to a more permanent bituminous surfacing. It is intended to carry traffic for a longer period than a prime.
Processing plant flow sheet A conceptual model that attempts to predict processing plant performance. The flow sheet forms the basis for the selection of equipment to meet the processing goals.
Procter Test a method to determine the maximum density that can be achieved through wetting and packing for a given aggregate.
Proctor See Standard Proctor.
Progressive / concurrent reclamation The practice of restoring a worked area at a site using soil, overburden and other materials removed in order to access a new section of the deposit, while extraction is going on elsewhere.
Proportioning Selection of proportions of ingredients for mortar or concrete to make the most economical use of available materials to produce mortar or concrete of the required properties.
Pugmill A stationary mechanical mixer for blending cement and aggregate.
Quality assurance The dependable and accurate monitoring and documentation process to assure that the products shipped do indeed meet aggregate specifications.
Quality control The process of controlling the quality of the aggregate and encompasses the processing plant design, the techniques implemented in processing, materials handling, stockpiling, and loadout.
Quarry Any site that is used for the extraction of rock from bedrock to be used for construction purposes.
Railway Ballast 50mm single sized aggregate to be laid as ballast under permanent way for construction and maintenance of rail track bed. The aggregate must conform to a grading requirement and certain specifications for physical properties, the most significant of which is the Wet Attrition Test. The current specification details a Wet Attrition Value of 6 maximum for high speed tracks and this excludes most limestone.
Reactive aggregate Aggregate containing substances certain silica or carbonate compounds that are capable of reacting chemically with the products of solution or hydration of the Portland cement (alkalis generally) in concrete or mortar, under ordinary conditions of exposure, resulting in harmful expansion, cracking, or staining.
Recycled aggregates Reprocessing of waste concrete and asphalt pavements into useable aggregates.
Rehabilitation The creation of landforms, land productivity and land uses that are compatible with existing land uses in the surrounding area.
Relative Density Samples soaked for 24 hours, weighed in distilled water, surface dried, and weighed and then over dried and weighed. Relative density range from 2.5 – 3.0.
Resistance Value (R Value) A test method to determine the Resistance to Lateral Deformation
Restoration The reformation of a quarry site or sand and gravel site back to agricultural use or leisure activities.
Revegetation The re-establishment of self-sustaining plant cover on a disturbed site.
Rip Rap Loose stone placed along a surface to prevent erosion, scour, or sloughing of a structure or surface such as breakwater, embankment, mountain trail, etc.
Roadbase A term used to describe crushed rock or natural gravel used in road construction.
Rock Pocket A portion of hardened concrete consisting of a concentration of coarse aggregate that is deficient in mortar; caused by separation during placement or insufficient consolidation, or both; see honeycomb.
Round rock aggregate Natural aggregate from either a fluvial or glaciofluvial deposit and comprised primarily of rounded particles created by mechanical erosion.
Run Of Quarry Material Stone blasted down from the quarry face but untreated in any way. Maximum size approximately 1m3. Sometimes sold for fill, dams, break-waters, sea defense etc.
Sampling The process of attaining a random and representative specified volume of an aggregate for testing.
sand Unconsolidated materials that are primarily composed of coarse, medium and fine mineral particles 4.76 mm (#4 sieve) to 0.074 mm (#200 sieve) in diameter.
Sand & Gravel Any clean, unconsolidated mixture of fine and/or coarse aggregate found in a natural deposit. Most sand & gravel deposits are formed by deposition of water.
Sand Equivalent Test (SE) A rapid field-correlation test to indicate the relative proportion of plastic fines and dust to sand size particles in granular soil and fine aggregate that pass the #4 sieve.
Saturated Surface Dry Density (SSD) The density calculated using the weight of the aggregate in a saturated surface dry state.
Scalpings Material removed to clean the run of quarry product either before or after the primary crusher – normally before. Consists of clay, muck etc. and the small flat particles from the blasted rock. Sized at either 75, 50 or 40mm down dependent on the cleanliness of the quarry and/or time of year. This is generally a saleable material as a good class fill for minor roads, foundations etc. Often slightly more rock than necessary is left in to upgrade the product and make it saleable. In some instances price is so good as to make it uneconomic to attempt to remove the rock but this is very dependent on the quantity of material “scalped”. Occasionally will meet the grading specification for Type 2 GSB with no further treatment.
Scarify Breaking up hard or compacted materials using a grader.
Screen Large vibrating sheet, or mat, of woven wire or polypropylene, with specific size holes through which aggregates fall through, and are collected.
Screened Aggregate Sand and gravel or crushed rock which has been separated by screens into various sizes. The separated sizes will usually differ dependent on whether it is a sand and gravel pit or a crushed rock plant. Sand and gravel usually produced to meet the requirements of BS882 (Aggregates from Natural Sources for Concrete) either as graded aggregates (40-5, 20-5, 14-5mm) or single sized (40, 20, 14, 10, 5mm). 3 fine aggregate gradings (C, M & F). Crushed rock produced in sizes to meet the requirements of BS63 (Road Aggregates) which are 50, 40, 28, 20, 14, 10, 6.3, 3mm and 3mm to dust.
Secondary Aggregates The waste products of other industries which can be used as a substitute for natural aggregates. For example incinerator bottom ash, crushed glass, china clay waste and slag.
Secondary Crusher This crusher is usually for re-crushing the primary crusher run smaller or rejects from the primary crusher run.
Sediment The very fine material within washing water and storm water runoff, originating from natural, mechanical and human disturbances. Sediment particles originate from the weathering and erosion of rocks or unconsolidated deposits and are transported by, suspended in, or deposited by water or air. Composed of clay, silt and sand.
Separation The tendency of coarse aggregate to separate from the concrete and accumulate at one side as concrete passes from the unconfined ends of chutes, conveyor belts, or similar arrangements.
Shell Content Content of shell particles in coarse aggregate passing a 10mm sieve and retained on a 5mm sieve.
Shock load The impact load of material such as aggregate or concrete as it is released or dumped during placement.
Shrinkage The property of the mortar in Portland Cement Concrete that undergoes shrinkage as it dries as a result of hydration and evaporation.
Silt Grains of rock between 0.002mm and 0.06mm
Silt Ponds/Lagoons The water used for washing and processing sand and gravel, ends up in ponds where the silt falls out and settles.
Single Size Aggregate An aggregate having a major proportion of particles lying between narrow size limits.
Site The land or water area where any facility or activity is physically located or conducted or all of the disturbed and undisturbed land within the legal boundaries of a property.
Skid Resistance The property of a paved surface that provides a resistance to skidding.
Slurry Seal A road surface treatment involving the application of a mixture of fine aggregate (5mm or 7mm) and emulsion in the form of a slurry over an existing pavement.
Sodium Soundness Test A test process used to determine the freeze-thaw characteristics of an aggregate.
Soil The unconsolidated material on the immediate surface of the land that serves as a natural medium for the growth of plants.
solubility The tendency of an aggregate to be dissolved by a liquid
Special provisions The section of a Project Bid Document that addresses special specifications that bidders must adhere to in submitting their bid documents.
Specific gravity The ratio of the mass of a given volume of aggregate to the mass of an equal volume of water.
stability The property which permits a combination of aggregate particles to remain stable and retain their load-carrying capabilities under various types of loading
Stakeholders All individuals, agencies, bodies, companies, etc. with an interest in a given matter.
Standard proctor A test that determines the maximum dry density for specific soil types. Specified compaction densities for fills are often based on a percentage of Standard Proctor for a specific moisture content.
Standards Levels of performance set by regulation or legislation.
Sterilization The removal of access, for whatever reason, to a potential aggregate site for extraction.
Stockpile Storage of an aggregate product in a large mound for later use, sale or disposal.
Stockpiling The practice of storing materials for later use, sale or disposal.
Storm water That portion of rainfall runoff that does not naturally seep into the ground or evaporate, but flows via overland flow, interflow, pipes and other features of a storm water drainage system.
Storm water drainage system Constructed and natural features that function together as a system to collect, convey, channel, hold, inhibit, retain, detain, infiltrate or divert storm water.
Strategic Highway Research Program (SHRP) $150 million research program funded by the federal government to improve highway construction practices and products.
Stripping The loss of adhesion between asphalt and aggregate due to moisture sensitivity.
Superpave The product of the American Strategic Highway Research Program (SHRP). Superpave (Superior Performing Asphalt Pavements) is an improved system for specifying the components of asphalt concrete, asphalt mixture design and analysis, and asphalt pavement performance prediction.
Surface moisture Free moisture retained on the surfaces of aggregate particles that becomes part of the mixing water in the concrete mix.
tack coat A light spray application of low viscosity asphalt emulsion (generally diluted) to an existing pavement surface to insure a bond between the original pavement and a subsequent asphalt concrete overlay
Timing windows A schedule of certain aggregate operations and mining activities to minimize environmental impacts.
Toast Rack A series of large concrete bays which different sizes of aggregate are stored.
Topsoil The upper-most soil layer that is commonly characterized by dark-colored, organically-enriched materials.
Toughness The resistance to fracture from impact. It is closely related to the absence of brittleness.
Uniformity Coefficient Test to determine relation of sieve size at which 60% of aggregate passes against the sieve size at which 10% passes. The result is expressed as a number; the higher the number the more blended the coarse and fine elements of the material. Commonly used in the DTp 600 series specifications for Earthworks, to determine suitability of material for various fills and back fills.
Vermiculite An aggregate somewhat similar to perlite that is used as an aggregate in lightweight roof decks and deck fills. It is formed from mica, a hydrous silicate with the ability of expanding on heating to form lightweight material with insulation quality. Used as bulk insulation and also as aggregate in insulating and acoustical plaster and in insulating concrete.
voids in aggregate mixture The spaces between aggregate particles
Washed Concrete Sand A commonly used term for BS882 fine aggregate sand, i.e. material generally passing a 5mm sieve. This can be further defined by grading into Coarse, Medium or Fine, depending upon the material’s natural composition and percentage of retention of particles on the 2.36mm sieve.
Washing Practice of cleaning aggregate with water to remove excessive amounts of fine particles.
Water Absorption The ability of an aggregate to absorb water 0.1 – 2% for normal road aggregates.
Water quality The chemical, physical, and biological characteristics of water, normally with respect to its suitability for a particular purpose.
Water table The upper surface or elevation of the groundwater within the aquifer that is closest to the ground surface.
Aggregate Abrasion Value (AAV)
Aggregate Crushing Value (ACV)
Aggregate Impact Value (AIV)
ambient water quality
Average Least Dimension (ALD)
average monthly discharge
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