Aggregates

Question 1

UK minerals [3]

Answer 1

coal, limestone/dolomite, sand/gravel

Question 2

value of UK minerals production 2004-2008

Answer 2

£25000 - £42000

Question 3

aggregate

Answer 3

angular rounded fragments or particles of relatively inert material that can be used with binding agents e.g. cement to form concrete/asphalt

Question 4

gravel use with binding agents not normally more than

Answer 4

37.5mm

Question 5

inhibit mixing and bonding with cement, generally removed by washing

Answer 5

FINES

Question 6

aggregates have a high place value

Answer 6

transport costs are high

Question 7

formation of glacial sand and gravels

Answer 7

glaciofluvial deposits formed by glacial melt waters washing away fines

Question 8

river sands and gravels

Answer 8

pleistocene, rivers fed by glacial meltwater carrying H2O and debris. spread sand/gravel across floodplains

Question 9

marine sands and gravels

Answer 9

lower sea level during pleistocene - dredging in up to 30m of water

Question 10

beach gravels

Answer 10

gravel and shingle beaches

Question 11

older deposits

Answer 11

unconsolidated e.g. triassic pebble beds

Question 12

local marine gravel extraction

Answer 12

near Isle of Wight

Question 13

sand and gravel extraction

Answer 13

unconsolidated so can be excavated and screened into different particle sizes; low proportion of fines to minimise washing

Question 14

overburden

Answer 14

removal to edge of site, depends on value of resource below

Question 15

Crushed rock

Answer 15

blasting of igneous and metamorphic rocks. 50% UK total production

Question 16

concrete

Answer 16

particles of aggregate coated and void space filled with cement

Question 17

aggregate shape

Answer 17

rounded is best to fill voids with cement

Question 18

aggregate size

Answer 18

coarse best for large vol, small amounts for fine aggregates

Question 19

aggregate grading

Answer 19

well graded with an ideal grading envelope

Question 20

aggregate surface texture

Answer 20

rough is ideal, but round is more workable

Question 21

aggregates contaminants

Answer 21

fines inhibit bonding, marine has salt

Question 22

aggregates in road construction

Answer 22

crushed rock
dense bitumen with aggregate
hot rolled asphalt with chippings

Question 23

Aggregate Impact Value

Answer 23

resistance to abrasion and polishing

20/10