59
2.712 .
So the sand can be used in the geopolymer concrete. The absorption of the split is 3.701
4. Water Content
The water content test of fine aggregate is equal to 1.6635 . The calculation of the water content of fine aggregate can be seen in appendix A.3
5.1.2. Investigate the Coarse Aggregate to Obtain the Result
1. Investigation of the organic matter content.
Coarse aggregate shall not contain the mud 1 greater than the density of dry oven. If the mud levels exceed 1, the coarse aggregate should be
washed, because of the high levels of mud would reduce bond coarse aggregate in the concrete mix. The investigation value of the mud in coarse
aggregate can be seen in Table 5.4.
Table 5.4 Investigation of Mud in the Coarse Aggregate
Investigation Weight
gram
Weight of coarse aggregate A
99.3
So, the amount of mud in the sand can be calculated as follow:
5-2
60
with:
W=
the amount of the mud in the coarse aggregate
A =
the weight of coarse aggregate after dried in the oven The amount of mud in coarse aggregate is 1 so that the coarse
aggregate can be used as the material of the specimen. 2.
Density and Absorption The result of the density and absorption test of coarse aggregate can be
seen in table 5.5. Table 5.5 Result of the Density and Absorption Test of Coarse Aggregate
Information Value
A Dry Weight Sample
500 gram B
Weight Sample SSD 505 gram
C Weight of Sample in the Water
293,5 gram D
Bulk Weight Density
C B
A
2,3711
E Bulk Weight Density SSD
C B
B
2,3948
F Weight Density
Apparent
C A
A
2,4289
G
Absorpti
on
100 x
A A
B
1
61
The coarse aggregate is restrained in the sieve no. 4 4.75mm. The weight of the sample is 500gr. From the requirement, the density of the coarse
aggregate for the normal concrete is around 2.4-3 grcm
3
. The density of this test is 2.3711. So the coarse aggregate can be used in the geopolymer
concrete. The absorption of the coarse aggregate is 1 3.
Water Content The water content test of coarse aggregate is equal to 1,342. The
calculation of the water content of coarse aggregate can be seen in appendix A.4
5.2. Slump Test
Slump test was conducted to measure the ease slump concrete mix to be done workability. Implementation procedures described in Chapter IV. The Value of
slump was affecting the strength of the concrete. The big value of slump will produce a bad concrete because it can produce a porous concrete. If the value of
the slump is too small the concrete will be difficult to be mixed. The tests carried out per variant slump value at age 14 and 28 days. Slump Test results is shown in
the table 5.6
62
Table 5.6 The Result of Slump Test at 14 days and 28 days
Varian Slump
Value 14 days
Slump Value
28 days
Metakaolin : Silica Fume cm
75:5 50:5
25:10 2
The differences value in the experiment is because the amount of additional water to make the mixture is easy to be done. If the amount of additional water is
high the mixture will be too wet and the value of the test will be higher.
5.3. Weight Density of Concrete
The types of concrete can be grouped based on the weight of the concrete type. Concrete grouping based on its density can be seen in Table 5.7.
Tabel 5.7 Specification of Weight Density of Concrete
Type Weight Density
grcm
3
Usage
Very Lightweight Concrete
1,00 Non Struktur
Lightweight Concrete 1,00-2,00
Lightweight Structure
Normal Concrete 2,30-2,50
Structure Weight Concrete
3,00 Light shield
Source: Tjokrodimuljo, 1992
