Paper • open access

Table 3
. Consistency, initial and final setting time results 
S/NO 
Mix ID 

PC (g) 
Materials 
RHA 
 
CCW 
 
MK 
Std 
Consistency 

IS 
(min) 
 
FS 
(min) 
Group 
1a 
100 % PC 
300 
- 
- 
- 
33.33 
45 
165 
Group 
1b, BM 
95PC- 5MK 
285 
- 
- 
15 
33.00 
80 
295 
90PC- 10MK 
270 
- 
- 
30 
34.00 
110 
295 
80PC- 20MK 
240 
- 
- 
60 
34.33 
85 
295 
Group 2, 
BM 
95PC- 5RHA 
285 
15 
- 
- 
32.67 
85 
225 
90PC- 10RHA 
270 
30 
- 
- 
33.67 
85 
250 
80PC- 20RHA 
240 
60 
- 
- 
35.00 
75 
325 
Group 3, 
BM 
95PC- 5CCW 
285 
- 
15 
- 
31.67 
105 
280 
90PC- 10CCW 
270 
- 
30 
- 
32.00 
60 
250 
80PC- 20CCW 
240 
- 
60 
- 
32.33 
70 
255 
Group 4, 
TM 
95PC- 5CCW-
5MK 
285 
- 
15 
15 
33.00 
123 
265 
90PC- 10CCW-
10MK 
270 
- 
15 
15 
34.67 
115 
275 
80PC- 20CCW-
20MK 
240 
- 
30 
30 
39.00 
145 
305 
Group 5, 
QM 
95PC-5CCW-
5RHA-5MK 
255 
15 
15 
15 
36.67 
90 
250 
90PC-10CCW-
10RHA-10MK 
210 
30 
30 
30 
42.33 
125 
270 
80PC-20CCW-
20RHA-20MK 
120 
60 
60 
60 
55.00 
110 
301 
This effect of RHA on IS depict disorder; but on FS, at 5 % level of replacement, it decreased by 
6 %; at 10 % level by 2 % and by 1 % at 20 % replacement level which showed that RHA 
progressively decreased FS of binders studied. This can be attributed to pozzolanic reaction of 
RHA at later stage. Similarly, when PC-CCW-MK is compared with PC-CCW, at 5 % level of 
replacement, decreased FS by 5 %, at 10 % level of replacement decreased by 1 % and then 
increased by 26 %. The effect of MK decreased FS by 5 % and 1 % at 5 and 10 % replacement 
levels but increased it by 26 % at 20 % replacement level. Furthermore, comparison between PC-
CCW-MK with PC-MK revealed that CCW prolonged IS by 35 %, 4 % and 41 % but decreased 
FS by 10 %, 7 % and 3 % at 5, 10 and 20 % replacement levels respectively. These results 

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Nanotechnology Applications in Africa: Opportunities and Constraints
IOP Conf. Series: Materials Science and Engineering 805 (2020) 012031
IOP Publishing
doi:10.1088/1757-899X/805/1/012031
11
showed that as % replacement level increased, IS is increased and then reduced FS which implies 
that reaction becomes faster at later stage of hydration. 
4
 
Conclusion 
From the analysis and discussion, results showed that the effect of the admixtures on standard 
consistency and setting times of the binders differs. The following conclusions are hereby drawn 
from the study:
i.
At 5 % replacement of PC with RHA, CCW, MK, influence on consistency is limited 
(< 9 %) but becomes significant (21 %) at 10 % and (39%) at 20 % replacement 
levels which are still within standard limits.
ii.
Standard consistency in quaternary binder (PC-CCW-RHA-MK) increased with 
increase in replacement level of PC with RHA due to high demand for water and its 
high specific surface area. This suggests that if percentage level of RHA is checked in 
binder, standard consistency requirements and water issues can be addressed. 
iii.
Replacement of PC by CCW, RHA, MK at 5 % level has negligible influence on 
consistency but at 20 % replacement level increased consistency which is at limits 
and similar to that of PC. This suggests that absorption and adsorption properties of 
CCW and MK are similar to that of PC.
iv.
When ternary (Group 4) binder, PC-CCW-MK is compared with quaternary, PC-
CCW-RHA-MK, with the addition of RHA, setting properties increased, suggesting 
that increase of pozzolanic materials increase hydration process leading to increase in 
time period. Delayed setting times is advantageous in that concrete can be worked for 
longer periods resulting in time delays in transport and between mixing and using 
concrete becomes less critical. This type of binder finds application in reduction of 
cold joints in larger concrete pours. 
v.
Setting time of quaternary binder increases at lower replacement level (5 %) of RHA 
but decreases at higher replacement level (20%) of RHA in the binder. This is due to 
the high specific surface area of RHA and MK which facilitates pozzolanic reaction 
with Ca(OH)
2
to speed up the hydration process. 
vi.
Retardation of setting time is the overall effect of CCW, RHA and MK on standard 
consistency and setting times (initial and final) of the quaternary binder. Since there is 

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Nanotechnology Applications in Africa: Opportunities and Constraints
IOP Conf. Series: Materials Science and Engineering 805 (2020) 012031
IOP Publishing
doi:10.1088/1757-899X/805/1/012031
12
less tri-calcium-aluminate (C
3
A) due to lower cement content, the influence of 
increasing levels of RHA is to provide greater retardation in the setting time. This 
type of binder (PC-CCW-RHA-MK) can be used in the manufacture of special types 
of concrete such as reinforced marine concrete (RMC) and also in construction works 
in marine areas with RMC where longer period is required for its placing.