Properties of Aggregates and its Values for use in Construction

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Properties of Aggregates and its Values for use in Construction

Properties of aggregates such as bulk density, specific gravity, voids, water absorption and its values are presented in this article.

1. Aggregates: Bulk Density, Specific Gravity and Voids

Bulk Density
River sand
Fine	1.44
Medium	1.52
Coarse	1.60
Beach or river shingle	1.60
Broken stone	1.60
Stone screenings	1.44
Broken Granite	1.68

Specific Gravity
Trap	2.9
Granite	2.8
Gravel	2.66
Sand	2.65

Voids, Percent, Average
River sand
Fine	43
Coarse	35
Mixed and moist	38
Mixed and dry	30
Broken stone, graded
25 mm maximum size	46
50 mm maximum size	45
63 mm maximum size	41
Stone screenings	48

Note: Above values are indicative only

2. Aggregates: Limiting Values of Mechanical Properties

Properties	Limiting Values (Percentage)
	For Wearing Surfaces	Other Than for Wearing Surfaces
Crushing value	30	45
Impact value	30	45
Abrasion value (Los Angeles)	30	50
Soundness (Average loss of weight after 5 cycles)	When tested with Na2SO4	When tested with MgSO4
Fine aggregates	10	15
Coarse aggregates	12	18

*Source- IS: 383 – 1970

3. Approximate Water Absorption of Aggregates, by Weight

Average sand	1.0 percent
Pebbles and crushed limestone	1.0 percent
Trap rock and granite	0.5 percent
Porous sandstone	0.5 percent
Very light and porous aggregates may absorb as much as	25 percent by weight

Note: The coarser the aggregate, the less free water it carries.

4. Limits of Deleterious Materials (Percentage by Weight, Maximum)

(Clause 3.2.1 of IS: 383 – 1970

Deleterious Substances	Fine Aggregates		Coarse Aggregates
	Uncrushed	Crushed	Uncrushed	Crushed
Coal and lignite	1.00	1.00	1.00	1.00
Clay lumps	1.00	1.00	1.00	1.00
Materials finer than 75-micron sieve	2.00	15.00	3.00	3.00
Shale	1.00	-	-	-
Total of percentages of all deleterious materials **	5.00	2.00	5.00	5.00

**Mica is excluded.

5. Bulking of Sands for Various Moisture Contents

Moisture, percent	Percentage bulking in
	Fine sand	Medium sand	Coarse sand
1	16	8	6
2	26	16	12
3	32	22	15
4	36	27	17
5	38	29	18
6	37	28	18
8	35	26	16
10	32	22	12
12	28	19	8
15	22	12	2
17	18	7	0
20	9	0	0
27	0	0	0

6. Surface Water Carried by Aggregates

Aggregates	Approximate Qty of Surface Water
	Percent by mass	Ltr./cu.m
Very wet sand	7.5	120
Moderately wet sand	5.0	80
Moist sand	2.5	40
Moist gravel or crushed rock	1.25 – 2.5	20 – 40

Note: Coarser the aggregate, less the water it will carry. Source: Table 10 of IS: 456 – 2000