Aggregate Absorption and SSD Moisture

A = \frac{W _{SSD} - W _{OD}}{W _{OD}}, M C = \frac{W _{stock} - W _{OD}}{W _{OD}}

Oven-dry (OD), saturated-surface-dry (SSD), and wet stockpile masses define absorption A and moisture content. Mix water is adjusted by (MC−A)×W_agg: free moisture if MC>A, absorption demand if MC<A.

$A$: Absorption (mass fraction)
$M C$: Total moisture content

Step-by-step solved example

OD=500 g, SSD=510 g, stock=525 g. A, MC, and free moisture?

OD / SSD / wet masses on a three-phase aggregate diagram.

1. A and MC
A=10/500=0.020=2.0%. MC=25/500=5.0%.
2. Free
(5−2)%×500=15 g free water on the aggregate.

Answer: A=2%, MC=5%, 15 g free water

10 practice questions

0/10 correct

1.SSD means

2.If MC=A the aggregate contributes

3.Bulk specific gravity (SSD) uses

4.Absorption of 0.6% on 1200 kg agg is

5.Lightweight aggregate often has

6.Free moisture is negative when

7.Apparent SG ignores

8.Correction of batch water is

9.W_SSD=2.050 kg, W_OD=2.000 kg: A =

10.ASTM coarse-aggregate SSD is obtained by