Paper • open access

2
Materials and experimental investigation 
2.1 Materials 
PC, CCW, RHA and MK were used in the production of quaternary paste binders. Tests were 
carried out on the physical and chemical properties of PC, CCW, RHA and MK to determine 
their suitability (Table 1). The mix proportions of the binder were divided into six groups: Group 
1a (100 % PC), Group 1b BM (PC + MK), Group 2 BM (PC + RHA), Group 3 BM (PC + 
CCW), Group 4 TM (PC + CCW+ MK), Group 5 QM (PC + CCW + RHA + MK) as indicated 
in Table 2. A local dealer of Dangote Cement Company, Nigeria provided the PC (CEM 1-42.5 
N). RH was incinerated in a local furnace for 3 h at 600 
o
C, and cooled to room temperature in a 
desiccator and then ground using a local mill and sieved through a 75 μm sieve to obtain RHA. 
Kaolin was obtained from Madagali, Yobe state, Nigeria and prepared and calcined at 700 
o
C for 
2 h at a rate of 10 
o
C/min at the Central Services Laboratory, National Cereals Research Institute, 
Badeggi, Niger State, Nigeria to obtain MK that was used for the study. It was then cooled to 
room temperature in a desiccator, ground with a local mill and sieved through a 75 μm sieve. 
CCW was obtained from a local panel beater at Katerin-Gwari, Minna, Nigeria. The CCW was 
air dried, sieved through a 75 μm sieve. Preliminary tests were carried out on the materials. 
2.2 Preparation of samples 
Six groups of paste samples were prepared using the admixtures RHA, CCW and MK which 
replaced PC at 5, 10 and 20 %. The constituents were thoroughly mixed on a glass sheet. The 
mixtures include 1 control sample of plain PC, 3 binary, 1 ternary and 1 quaternary mixture. PC 
was partially replaced by RHA, CCW, and MK at replacement levels of 0, 5, 10 and 20 %.
Maximum replacement of PC by supplementary materials was 20 % by mass for all mixtures 
(Table 2). 

---

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
6
2.3 Methods 
For the determination of consistency and setting times of PC, PC-RHA, PC –CCW and PC-MK 
pastes, six groups of samples were tested. The normal consistency and setting time tests were 
conducted in accordance with BS EN 196-3 provisions [31]. The normal consistency, setting 
times (initial and final) of PC pastes were determined using Vicat apparatus in accordance with 
ASTM C 191 [32]. The water of consistency and setting times of the prepared pastes were 
directly determined from the relation in equation (2)
WC (%) = L/W x 100 (2) 
Where WC is consistency water, L is water required to produce a suitable paste and W is the 
mass of cement sample (300g).
The initial setting time is the time taken to reach the initial set, while the final setting time is the 
time taken to attain final set of paste. Using the Vicat apparatus, a needle of 1 mm square 
penetrated the paste at every 10 min interval till the index scale showed 5 + 0.5 mm from bottom 
of the mould. For the final setting time, the needle was replaced with an annular attachment. The 
needle was released every 30 min interval until it makes no visible indentation on the test 
specimen surface. For each mixed sample, three tests were carried out and the mean result was 
recorded.