Table 3 . Physical properties of aggregates
Properties Sand Fine CBA Granite Coarse CBA
Oven dry basis , bulk density ( kg / m 3 ) |
1624 |
910 |
1580 |
770 |
Specific gravity |
2.62 |
1.75 |
2.7 |
1.22 |
Water absorption at 24 hours (%) |
3.4 |
34.6 |
1.8 |
20 |
Crushing Index Value (%) |
- |
- |
20 |
31 |
Figure 2 . Sieve analysis of coarse and fine aggregates
Figure 3 . Sieve analysis of coarse and fine aggregates
Grading of CBA In order to use coal bottom ash as aggregates in concrete , the grade of the coal bottom ash has to pass the sieve analysis test and be compared with sand and granite . The sieve analysis of granite and coarse bottom ash is shown in Figure 2 while the sieve analysis of fine coal bottom ash and sand is shown in Figure 3 . ASTM C33-13 provided the basis for deriving the lower and upper limits [ 17 ]. From the sieve analysis , it can be seen that the particle distribution of coal bottom ash used in this research followed the overall limit by ASTM C33-13 . Therefore , coal bottom ash can be used as an aggregate to replace sand and granite since a stable and robust concrete is normally generated from the aggregates within the grading limits of the ASTM C33-13 . Enhanced concrete workability , robustness , as well as packaging density is achieved from aggregates that are graded properly to minimise the need for water [ 18 ].
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