The table below shows the sieve analysis results of aggregates from four (A, B, C, D) stockpiles. (1) Plot the cumulative percent passing versus sieve size on the following 0.45 gradation chart for the four types of aggregates. (2) The grading envelope required in AS2150 for Asphalt Concrete (AC20 and AC28) for each sieve size is given in the table below, draw the graph to show each grading envelope on the 0.45 gradation chart. (3) Given the proportion for each type of aggregates used in the following blended aggregate (A30%, B40%, C20%, and D10%), calculate their size distribution and plot their cumulative percent passing versus sieve size. Does the blended aggregate meet the requirement for AC20 or AC28? If not, how to adjust the proportion of each type of aggregates to produce a blended aggregate that meets the requirement?
Sieve size (mm)
Aggregate AC20 AC28 Blend envelope 30/40/20/10 % passing
100 110 100 100 100 100
65 100 100 100 90-100
34 65 100 100 58-75
10 35 100 100 37-55
30-50 15 83 86 24-42
20-37 2 5 55 45 15-32
13-28 2 3 35 34 10-24
9-22 2 2 22 25 7-17
6-16 2 2 15 14 4-12
4-10 2 1 8 5 3-6
3-6
37.5
19.0
9.5
4.75
2.36
1.18
0.6
0.3
0.15
0.075
Sieve Size