Question

An asphalt concrete mixture includes 94% aggregate by weight. The specific gravities of aggregate and asphalt are 2.65 and 1.0, respectively. The unit weight of water is 62.4 lb/ft3. The total weight of the mix is 147 Ib and the total volume is 1 ft3. Ignoring absorption, what is the percent voids in the total mix

Answer 1

percent voids = 2.36%

Step-by-step explanation:

Theoretical specific gravity ( Gt ) = ( w1 + wL ) / (( w1/G1) + (wL/GL ) )

= ( 94 + 6 ) / ((94/2.65) + ( 6 / 1.0 ))

∴ Gt = 2.411

next determine mass specific gravity = Ym / 1000

Bulk density = mass / volume = 147 Ib / 1ft^3 = 147 Ib/ft^3

given that: 1 Ib/ft^3 = 16.018 kg/m63

147 Ib/ft^3 = 2354.646 kg/m^3 ( Ym )

hence mass specific gravity = 2354.646 kg/m^3 / 1000

Gm = 2.354

finally determine percent void

= ( Gt - Gm ) / ( Gt ) * 100

= ( 2.411 - 2.354 ) / ( 2.411 ) * 100

= 2.36 %