Page 45 - Lecture Notes DCC3113

v. Soundness

To determine resistance to disintegration due to cycle of wetting and drying, heating and
cooling (weathering). Aggregates are soaked in solution of sodium or magnesium sulphate
for 16-18 hours. Remove sample and put in oven at 105C or 16-18 hours. Repeat the same
process until complete 5 circles. Then wash and dry the sample. Sieve the sample and
calculate:

Result before and
after soaked in
solution

Figure 3-11: Soundness

vi. Flakiness Index

To determine percentage of flaky aggregate. An aggregate is considered
flaky when its thickness is less than 0.6 times its average dimension.
Aggregate that needs to be tested is between 6.3 mm and 63 mm.
Aggregate according to the size and weight is recorded. Each aggregate
is to be inserted to the specific slot and record the weight of passing
aggregate. Aggregate passes the slot is considered flaky.

Sample of flaky
aggregate

Fig ure 3-12: Flakiness Index Equipment

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