8/11/2019 Construction Aggregate

1/14

Construction Aggregate

8/11/2019 Construction Aggregate

2/14

IntroductionConstruction aggregate is a broad category of coarseparticulate material used in construction, including crushedstone, sand, gravel, slag, recycled concrete andgeosynthetic aggregates .

Aggregates are the most mined materials in the world.Construction aggregates are the least expensive of allmined products. Because of their low price, transportationcosts from the mine to the point of use often are the majorpart of their cost to the consumer.

8/11/2019 Construction Aggregate

3/14

IntroductionSand and gravel aggregate is less expensive than crushedstone aggregate, but crushed stone has the advantage ofconsistency in mineral makeup, hardness, angularity, anddensity.Recycled aggregate is usually highly variable in quality andproperties.Modern blasting methods enabled the developmentof quarries, which are now used wherever competentbedrock deposits of aggregate quality exist like limestone,granite, and marble

8/11/2019 Construction Aggregate

4/14

UsesConstruction aggregates are used in concrete and asphalt,which make up most of our streets and highways, bridges,houses and other buildings, roofing, and other structuralcomponents.

Aggregates range in size from large boulders (rip rap) usedas fill in large construction projects to finely-ground flour-sized particles used in paint, glass, plastic, medicine,agricultural feed and soil conditioners, and many otherindustrial and household products.Construction aggregates are also used in water purification,emissions control, soil erosion control, and otherenvironmental improvement products.

8/11/2019 Construction Aggregate

5/14

Crushed stone By blasting, crushing and screening, quarries produce arange of products including (1)coarse-screened rock for railballast, (2)screenings for concrete, road sealing and hotmixaggregates, and (3)crushed rock and rubble for roadpavements. Those that are too large for the crushers tohandle are often stockpiled for use in (4)breakwater

construction or beach protection worksThe rock type quarried can be any material that exhibitssufficient strength, resistance to wear, high productionpotential, and low amount of waste. Limestone is thepreferred rock for highway construction

8/11/2019 Construction Aggregate

6/14

8/11/2019 Construction Aggregate

7/14

Natural sandNatural sand is used for a variety of purposes for which thereis a range of specifications, principally size gradings and siltand clay content. The most important use of natural sand isin concrete, which accounts for over half of all sandproduced. Other significant uses include bricklaying,plastering, filling on building sites, packing of water or gas

pipeline trenches, and for gardening.

8/11/2019 Construction Aggregate

8/14

8/11/2019 Construction Aggregate

9/14

8/11/2019 Construction Aggregate

10/14

8/11/2019 Construction Aggregate

11/14

Other Construction

Aggregate

8/11/2019 Construction Aggregate

12/14

SlagSlag is the glass-like by-product left over after a desiredmetal has been separated (smelted) from its raw ore.If the granulated blast furnace slag accesses free lime duringhydration, it develops strong hydraulic cementitiousproperties and can partly substitute for portland cement inconcrete

8/11/2019 Construction Aggregate

13/14

Recyclable aggregate Aggregates themselves can be recycled as aggregates.Unlike deposits of sand and gravel or stone suitable forcrushing into aggregate, which can be anywhere and mayrequire overburden removal and/or blasting, "deposits" ofrecyclable aggregate tend to be concentrated near urbanareasConcrete, asphalt, glass

8/11/2019 Construction Aggregate

14/14