G-2 Select Concrete Forming Systems

Question 1

Slab-on-ground

Answer 1

main factor of this is to get the top of the form straight. subgrade must be very packed and made from materials that can drain.

Question 2

Footings

Answer 2

usually buried and and are not architectural. normally simple latter forms with 2x4 cleats.

Question 3

Foundation walls

Answer 3

this will depend on the system available for the contractor.

Question 4

Above grade walls

Answer 4

usually architectural. must make sure they are straight smooth and flat. vibration of different layers is important for mixture of layers.

Question 5

Columns

Answer 5

Columns require the strongest forms because they are often tall and concrete is placed al in one placement.

extensions to concrete hose may be needed to get concrete as close to placement as possible.

Question 6

Beams and Girders

Answer 6

pressure on girders and beams is not as bis on those of columns or walls. the most important concern for beams and girders is the falsework that support them. they must be able to carry load of fresh concrete snd equipment used

Question 7

Suspended slabs

Answer 7

often formwork is prefab and can be easily set up and moved around

Question 8

Pre-cast concrete

Answer 8

formwork for precast must be able to take heavy use. normally made from steel and can withstand high temperatures

Question 9

True or false, air temperature will affect setting and rate of placement for concrete?

Answer 9

True

Question 10

If temperature rises the rate of placement should?

Answer 10

Increase and other way around

Question 11

Slump

Answer 11

sump is a measurement of concretes consistency.

Question 12

low slump

Answer 12

stiff and hard to work with

Question 13

high slump

Answer 13

fluid and easy to place

Question 14

Flow table test is used to?

Answer 14

Used for assessing concrete that is too fluid to be measured with slump test

Question 15

Vibration

Answer 15

used to consolidate the concrete into the forms and around the reinforcing steel.

Question 16

Form size

Answer 16

Pressure at the bottom of a form that is the same height regardless of width is the same.

Question 17

Architectural concrete

Answer 17

concrete that is left exposed after building is finished.

Question 18

Waste moulds

Answer 18

some forms are built with lath and plaster to allow complicated details. to remove such formwork it must be destroyed.

Question 19

Fibreglass Forms

Answer 19

reusable fibreglass moulds for concrete

Question 20

to prevent leakage of cement paste**?

Answer 20

formwork must be water tight with all corners pressure locked together.

Question 21

Test block

Answer 21

should be used before finishing finished concrete (sandblasting, coloured, tooling)

Question 22

Sandblasting

Answer 22

very common finish for architectural concrete. Produces a fine texture

Question 23

Tooling

Answer 23

this created a rough surface. rarely don because labour intensive

Question 24

Exposed aggregate

Answer 24

used extensively for exterior concrete work (jordans pad)
. special restarted is used to prevent concrete from setting then after 12 hours, the surface is hosed off to reveal aggregate

runoff cannot go into drain
must be sprayed with curing agent immediately after washing

Question 25

Rustication strips

Answer 25

often used for form patterns n concrete and hide control joints. strips are made so they can be easily stripped special saw kerf is added and they are soaked in form oil.

Question 26

Form liners

Answer 26

used to make decretive finish to the surface of concrete walls.

Question 27

Telegraphing

Answer 27

irregularities in the form surfaces that transfer to the finished concrete and still show up after sandblasting.