Aggregates

Aggregates

generally refers to mineral particles which have rock as their origin unless otherwise specified.

Rock

includes any large solid mass of mineral matter which is part of the earth's crust.

Igneous Rock

was at one time molten and cooled to its present form.

Sedimentary Rock

was at one time consisted of particles deposited as sediment by water, wind or glacier.

Metamorphic Rock

is either igneous or sedimentary rock that has been changed in

texture, structure and mineral composition or in or two of these characteristics, by intense geologic heat or pressure or both.

Coarse aggregate

(1) aggregate predominantly retained on the No. 4 (4.76-mm) sieve; or (2) that portion of an aggregate retained on the No. 4 (4.76-mm) sieve.

Fine aggregate

aggregate passing the 3/8-in. sieve and almost entirely passing the no. 4 (4.76-mm) sieve and predominantly retained on the No. 200 (74-micron) sieve; or (2) that portion of an aggregate

passing the No. 4 (4.76-mm) sieve and retained on the No. 200 (74-micron) sieve.

Gravel

(1) granular material predominantly retained on the No. 4 (4.76-mm) sieve and resulting from natural disintegration and abrasion of rock or processing of weakly bound conglomerate; or (2) that portion of an aggregate retained on the No. 4 (4.76-

mm) sieve and resulting from natural disintegration

and abrasion of rock or processing of weakly bound

conglomerate.

Sand

(1) granular material passing the 3/8-in. sieve

and almost entirely passing the No. 4 (4.76-mm) sieve

and predominantly retained on the No. 200 (74-

micron) sieve, and resulting from natural

disintegration and abrasion of rock or processing of

completely friable sandstone; or (2) that portion of an

aggregate passing the No. 4 (4.76-mm) sieve and

predominantly retained on the No. 200 (74-micron)

sieve,

Bank gravel

found in natural deposits, usually more or less intermixed with fine material, such as sand or clay, or combination thereof; gravelly clay, gravelly sand, clayey gravel, and sandy gravel indicate the varying proportions of the materials in the

mixture.

Crushed gravel

the product resulting from the artificial crushing of gravel with substantially all fragments having at least one face resulting from fracture.

Crushed stone

The product results from the artificial crushing of rocks, boulders, or large cobblestones, substantially all faces of which have resulted from the crushing operation.

Crushed rock

the product resulting from the artificial crushing of all rock, all faces of which have resulted from the crushing operation or from blasting.

Blast-furnace slag

the non-metallic product, consisting essentially of silicates and aluminosilicates of lime and of other bases, which is developed in a molten condition simultaneously with iron in a blast furnace.

Natural

gravel pits, river run deposits, and rock quarries. are ______ aggregates

Manufactured

_________ aggregates can use slag waste from steel mills and expanded shale and clays to produce lightweight aggregates.

Gradation

the distribution of sizes within the range covered. Range of sizes are the smallest and largest particles.

Sieve Analysis

________ is used primarily to determine the grading of materials proposed for use as aggregates or being used as aggregates

Gradation Chart

______ a graph of percent by weight versus sieve sizes.

Effective Size D10

used to designate size of aggregate to be used as a filter for sewage or drinking water, is that diameter or size on the graph which has 10 percent of the total finer than its size.

Maximum Size of Aggregate

when used in the design of Portland cement concrete mixes, is taken for that purpose to be the size of the sieve next above the largest sieve that has 15 percent of the total sample coarser than it (cumulative percentage retained).

Fineness Modulus

is a value used in the design of Portland cement concrete mixes to indicate the average size of fine aggregate.

Uniformity Coefficient

is a mathematical indication of how uniform the aggregate is.

Bulk Volume

is the volume of aggregate that may include solid matter, plus pores in the particles, plus voids.

Saturated Surface - Dry Volume

is the volume that may include solid matter, plus pores in the particles but not voids.

Solid Volume

is the volume that may include solid matter only, not pores or voids.

Wet Weight

is the weight that may include solid matter, plus enough water to fill the pores, plus free water on the particles surface.

Saturated Surface - Dry Weight

is the weight that may include solid matter, plus enough water to fill the pores.

Oven - Dry Weight

is the weight that may include solid matter only.

Friable particles

are those which are easily crumbled, such as clay lumps, weak

sandstone, or oxidized ores.

Material finer than No. 200 sieve

is that material which passes through the No. 200

sieve in a washed sieve analysis performed according to ASTM C117.

Soft particles

are those that are marked with a groove after being scratched on a freshly broken surface by a pointed brass rod under a force of 2 lb in accordance with ASTM C235, Test for Scratch Hardness of Coarse Aggregate Particles.

Lightweight pieces

are particles in coarse or fine aggregate that have an

SG substantially less than that of the aggregate as a whole.

Organic impurities

are non-mineral material of an organic type, mainly

tannic acid, sometimes found in fine aggregate.

Reactive aggregates

are those which contain minerals which react with alkalis in Portland cement, causing excessive expansion of mortar or concrete.

Toughness

means resistance to abrasion and impact.

Soundness

of aggregates means resistance to disintegration under weathering including alternate heating and cooling, wetting and drying, and freezing and thawing.

Hydrophilic

aggregates does not maintain adhesion to asphalt when it becomes wet.

Compaction

is the densification of a material resulting in an increase in weight per unit volume.

Permeability

is a measure of the ease with which a fluid, most commonly water, will flow through a material.