CHAPTER 5
CONCLUSION AND RECOMMENDATION
5.1
Conclusion
From the overall results of analysis, it is able to establish the correlation
factor between river sand and silica sand. The river sand shows 1 percent to 1.5
percent higher dry density value compared to the silica sand dry density value when
tested in-situ. The lowest dry density achieved from the in situ field density test was
1.095 Mg/m3 and 1.114 Mg/m3 using silica sand and river sand respectively.
Whereas, the highest dry density achieved from the in situ field density test were
1.315 Mg/m3 and 1.344 Mg/m3 using silica sand and river sand respectively.
Through the tests conducted at the selected site, the silica sand shows lower
dry density value due to the lower particle density value of river sand compared with
the silica sand. The particle density tested for river sand and silica sand was 2.637
Mg/m3 and 2.646 Mg/m3 respectively.
The silica sand is the standard sand that is allowed by British Standard 1377
Part 9 of soil testing for using to conduct the field density test using sand
replacement method. Thus, the test result will reflect the compactness of the site. If
the dry density
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at the site fall below the specification of testing, then the site has to be re-compacted
in order to reach the qualify margin of the test specification.
When the field density tests conducted using river sand, the dry density
obtained from the selected site is higher compared to the silica sand. For all the tests
have been done, the results are similar. Thus, if the river sand is to be used as an
alternative material, when conducting the in-situ field density test, the test
specification has to be raised up to 2 percent. If the test specification is 95 percent
for silica sand, then for river sand will have to be raised up to 97 percent. If the dry
density obtained from the used of river sand and to convert to dry density obtained
by using silica sand, the converting factor is 0.9813 as extracted from the
relationship graph.
From the economy point of view, river sand is more economy to be used as
the alternative material for conducting the field density test. It is because river sand
can be found easily around Sarawak rivers. If to purchase river sand, it is cheaper
compared to Silica sand. Furthermore, silica sand can be used for other purposes
such as making glass.
5.2
Recommendation
In order to produce more clear and reliable result, it is recommended that;
1)
The number of in-situ testing has to be increased, so that more data can be
obtained and increase the accuracy of the analysis.
2)
Additional sites may be selected for more tests to be carried out. This is
because the material use as subgrade will be different, therefore the result of the field
density tests will be more general.
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3)
If the test can be carried out within a short period so that the moisture
content of the ground not varies much, then the accuracy of the result will be higher.
4)
The river sand can be provided from various sources or from different rivers,
so that the result of the test and comparison can be more general.
5)
The moisture content may play an important role on the analysis. Therefore
if moisture content on the ground can be controlled during the test, the result will be
more accurate.
6)
If the test is to be carried out by controlling the number of passes each time,
then it will show various degree of the dry density. For comparison of the density
and establishing of correlation factor will be more clear and reliable