MIX design of ASPHALT CONCRETE

Question 1

Durability: max at ___ A.C
Workability: max at ___ A.C
Stability: max at ___ A.C
Flexibility: max at ___ A.C

Answer 1

Durability: max at high A.C
Workability: max at high A.C
Stability: max at low A.C
Flexibility: max at high A.C

Question 2

What are the 3 basic for mix design of asphalt concrete?

Answer 2

Agg. selection
Asphalt binder selection (just select)
Find optimum asphalt binder content

Question 3

How to mathematically do the agg. selection?

Answer 3

aA+bB=T
where:
a=% of agg. A (<1)
b=% of agg. B (<1)
and a+b=1 (when b is 0, A=T/a)

Question 4

How to find the optimum asphalt binder content?

Answer 4

1. find in given values in problem –> Pb(%asphalt cement); Ps (%agg= 100-Pb); Gmm (maximum specific gravity of mix); Gb( specific gravity A.C)
2. find effective specific gravity in problem using formula (stay constant)
3. find Gmm for all % A.C using Gse
4. compute VTM using formula for all A.C
5. compute VMA using formula for all A.C
6. compute VFA