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ACID-SOLUBLE MATERIAL:
This is 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.
ADMIXTURES:
Chemicals or agents added to concrete in its fluid state to enhance certain properties.
AGGREGATE ABRASION VALUE. (A.A.V.):
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 is the A.A.V. Results range from 1(some flints) to 15 (normally regarded as too soft for use in wearing course) LOW RESULT BEST.
AGGREGATE CRUSHING VALUE. (A.C.V.):
14mm - 10mm chippings subjected to 400 Kn. load evenly over 10 minutes. Sieved on 2.36mm sieve. Percentage passing is A.C.V. Results range 10 (very strong) to 35 (normally regarded as too weak for use in road surfacing). LOW RESULTS BEST.
AGGREGATE IMPACT VALUE. (A.I.V.):
As for A.C.V. but subjected to 15 blows impact using standard apparatus. Similar results to Aggregate Crushing Value except for brittle rocks, e.g. Quartzite and hard grit stones, which can be up to 3 points higher. LOW RESULT BEST.
AGGREGATE:
A granular material obtained by processing natural materials. BS882 splits aggregate into coarse and fine elements, coarse being described as gravel (crushed, uncrushed or partially crushed) or crushed rock and fine being described as sand (see further definitions, coarse aggregate, fine aggregate etc)
AGLIME:
Ground limestone. 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 40% will pass through a 150 micron sieve. (See Maglime.)
AGRICULTURAL DUST:
Screened limestone. 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 lass than 20% will pass through a 150 micron sieve.
AIR ENTRAINED CONCRETE:
Concrete design including the AEA admixture. All concrete is porous to some degree which means that it is susceptible to water absorption. If this water freezes, it will expand and can damage the surface of the concrete. Addition of an Air-Entraining agent creates microscopic bubbles in the hardened concrete which provide spaces for the freezing water to expand into, thereby preventing or reducing the effects of freezing on the finished surface. All hard standing areas such as driveways and paths should contain an AEA.
AIR ENTRAINING AGENT (AEA):
Designed to create microscopic bubbles within hardened concrete, giving moisture a void into which to expand if freezing takes place.
ALL-IN AGGREGATE:
Aggregate consisting of a mixture of coarse aggregate and sand. It may be produced without separating into coarse and fine fractions, or by combining coarse aggregate and sand.
ARMOUR STONE:
Large pieces of rock between 1 tonne and 15 tonnes for sea defence or river defence.
ARTICS:
Short term for articulated vehicles.
AS DUG:
Raw mineral as it is found in the ground or after blasting from quarry face.
AS RAISED:
Similar to 'as dug' but usually used in reference to sand and gravel deposits especially when the mineral is won from below water. A commonly used term for Ballast As Dredged for marine sourced materials.
ASPHALTIC CEMENT:
Bitumen, alone or mixed with either a volatile or non-volatile diluents, with or without the addition of fine mineral matter, forming a cement suitable for binding aggregate into coherent road material.
ASPHALT, HOT ROLLED (HRA):
An old name for Rolled Asphalt
ASPHALT, LAKE:
A naturally occurring mixture of bitumen and finely divided mineral matter, which is found in well-defined surface deposits.
ASPHALT, MASTIC:
A mixture of fine mineral matter and bitumen or asphalted cement forming a mixture free from voids which, when heated, can be spread by hand floats.
ASPHALT, NATURAL:
Asphalts, which occur naturally. (Two forms are used in road construction 'Lake Asphalt' and 'Rock Asphalt'.)
ASPHALT, ROCK:
A limestone or sandstone naturally impregnated with bitumen. Only limestone rock asphalt is used in road construction.
ASPHALT, ROLLED:
A hot-processed material consisting of a mixture of relatively hard bitumen with aggregates in such gradings as to produce a definite gap between the coarse and the fine elements. When hot, it can be spread by rakes or mechanical spreader and compacted with a roller. Wearing course rolled asphalt is a close-textured material, which after compaction is impervious throughout the full depth of the wearing course. Wearing courses often have pre-coated chippings rolled in for anti-skid purposes.
ASPHALT:
A natural or artificial mixture in which bitumen is intimately associated with a substantial proportion of solid mineral matter. (N.B. In the United States of America the term 'asphalt' denotes what in this country is termed 'bitumen'.)
ATTRITION VALUE:
Obsolete test for road stone but still used by British Rail for testing track ballast. Passing 50 mm retained on 37.5mm chippings placed in iron cylinders inclined at 30o and rotated 10000 times. Percentage passing 2.36mm sieve after the test is the Attrition Value. LOW RESULTS BEST. Dry attrition values and wet attrition values are determined but emphasis on wet attrition value by British Rail who normally requires values of less than 6 for high-speed tracks.
AUGER:
The part at the rear of a laying machine which moves material from the centre to the sides, often referred to as the 'screws', before the material goes beneath the screed.
A.O.N.B:
Area of Outstanding Natural Beauty, area defined by county councils which will have restrictions on planning.
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